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Question 1
Correct
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You are reviewing a patient complaining of loss of vision. Previous images shows a lesion at the optic chiasm. What type of visual field defect are you most likely to see in a lesion at the optic chiasm:
Your Answer: Bitemporal hemianopia
Explanation:A lesion at the optic chiasm will result in a bitemporal hemianopia.
A lesion of the optic nerve will result in ipsilateral monocular visual loss.
A lesion of the optic tract will result in a contralateral homonymous hemianopia. -
This question is part of the following fields:
- Anatomy
- Central Nervous System
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Question 2
Correct
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Cefotaxime (or ceftriaxone) is used first line for which of the following infections:
Your Answer: Blind treatment of suspected bacterial meningitis
Explanation:Cefotaxime (or ceftriaxone) are indicated first line in:
– Blind treatment of meningitis in patients > 3 months (with amoxicillin if patient > 50 years)
– Meningitis caused by meningococci
– Meningitis caused by pneumococci
– Meningitis caused by H. influenzae
– Severe or invasive salmonellosis
– Typhoid fever
– Gonorrhoea
– Gonococcal arthritis
– Haemophilus influenzae epiglottitis -
This question is part of the following fields:
- Infections
- Pharmacology
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Question 3
Incorrect
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What proportion of peripheral blood leukocytes are monocytes?
Your Answer: < 1%
Correct Answer: 5 - 10%
Explanation:Monocytes account for around 5 to 10% of peripheral white cells. Monocytes in peripheral blood are generally bigger than other leukocytes and feature a large central oval or indented nucleus with clumped chromatin. The abundant cytoplasm staining blue and containing numerous fine vacuoles gives the appearance of ground glass. Cytoplasmic granules are another type of granule.
Monocytes evolve from the granulocyte-macrophage progenitor to become monoblasts, promonocytes, monocytes, and tissue macrophages (in increasing order of maturity). Monocytes only stay in the bone marrow for a short time before exiting to circulate in the bloodstream for 20-40 hours before becoming macrophages.
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This question is part of the following fields:
- Immune Responses
- Pathology
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Question 4
Correct
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A blood transfusion is given to a 52-year-old woman. She develops chills and rigours shortly after the transfusion begins.
The following are her observations: Temperature 40°C, HR 116 bpm, BP 80/48, SaO 2 97 percent on air.
Which of the following treatments is the most appropriate?Your Answer: Stop the transfusion and administer antibiotics
Explanation:Bacterial infections are common in the following situations:
Platelet transfusions are associated with a higher risk of bacterial infection (as platelets are stored at room temperature)
Immersion in a water bath thawed previously frozen components.
Components of red blood cells that have been stored for several weeks
Gram-positive and Gram-negative bacteria have both been linked to transfusion-transmitted bacterial infection, but Gram-negative bacteria are linked to a higher rate of morbidity and mortality.
Yersinia enterocolitica is the most common bacterial organism linked to transfusion-transmitted bacterial infection. This organism can multiply at low temperatures while also utilising iron as a nutrient. As a result, it’s well-suited to proliferating in blood banks.The following are some of the most common clinical signs and symptoms of a bacterial infection transmitted through a blood transfusion. These symptoms usually appear shortly after the transfusion begins:
Fever is very high.
Rigours and chills
Vomiting and nausea
Tachycardia
Hypotension
Collapse of the circulatory systemIf a bacterial infection from a transfusion is suspected, the transfusion should be stopped right away. Blood cultures and a Gram stain should be requested, as well as broad-spectrum antibiotics. In addition, the blood pack should be returned to the blood bank for an urgent culture and Gram-stain.
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This question is part of the following fields:
- Haematology
- Pathology
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Question 5
Correct
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Question 6
Correct
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Which cervical interspace is most likely injured if a patient presents with difficulty of shoulder abduction and elbow flexion, pain in the right shoulder and lateral arm, and decreased sensation over the deltoid and lateral arm?
Your Answer: C4-C5
Explanation:In the setting of cervical radiculopathy, because the nerve root of a spinal nerve is compressed or otherwise impaired, the pain and symptomatology can spread far from the neck and radiates to arm, neck, chest, upper back and/or shoulders. Often muscle weakness and impaired deep tendon reflexes are noted along the course of the spinal nerve.
Cervical radiculopathy is almost always unilateral, although, in rare cases, both nerves at a given level may be impacted. Those rare presentations can confound physical diagnosis and require acceleration to advanced imaging especially in cases of trauma. If there is nerve impingement, the affected side will be reduced relative to the unaffected side. Reduction in strength of muscles innervated by the affected nerve is also significant physical finding.
For a C4-C5 injury, the following symptoms may present:
Weakness in the deltoid muscle (front and side of the shoulder) and upper arm
Shoulder pain
Numbness along the outside of the upper arm -
This question is part of the following fields:
- Anatomy
- Head And Neck
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Question 7
Correct
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Fracture of the medial epicondyle would result to the following, except
Your Answer: Weakness of abduction of the thumb
Explanation:Thumb abduction is mediated by the abductor pollicis longus and brevis, which are innervated by the radial and median nerves, respectively.
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This question is part of the following fields:
- Anatomy
- Upper Limb
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Question 8
Incorrect
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Where:
Capillary hydrostatic pressure is (P c)Hydrostatic pressure in the interstices is (P I )
Plasma oncotic pressure is (π p)Interstitial oncotic pressure is (π i)
Which of the following formulas best represents fluid flow at the capillary bed?
Your Answer: Volume / min = (P c - P i ) - (π i - π p )
Correct Answer: Volume / min = (P c - P i ) - (π p - π i )
Explanation:Starling’s equation for fluid filtration describes fluid flow at the capillary bed.
Filtration forces (capillary hydrostatic pressure and interstitial oncotic pressure) stimulate fluid movement out of the capillary, while resorption forces promote fluid movement into the capillary (interstitial hydrostatic pressure and plasma oncotic pressure). Although the forces fluctuate along the length of the capillary bed, overall filtration is achieved.At the capillary bed, there is fluid movement.
The reflection coefficient (σ), the surface area accessible (S), and the hydraulic conductance of the wall (Lp) are frequently used to account for the endothelium’s semi-permeability, yielding:
Volume / min = LpS [(Pc- Pi) – σ(πp– πi)]
Volume /min = (Pc-Pi) – (πp–πi) describes the fluid circulation at the capillaries.
Where:
Pc= capillary hydrostatic pressure
Pi= interstitial hydrostatic pressure
πp= plasma oncotic pressure
πi= interstitial oncotic pressure -
This question is part of the following fields:
- Cardiovascular Physiology
- Physiology
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Question 9
Correct
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Among the following microorganisms, which is considered to be transmitted by invasion of intact skin?
Your Answer: Leptospira spp.
Explanation:Rodents and domestic animals are the primary reservoirs for the Leptospira spp, although other animals, including cows, horses, mongooses, and frogs, can also harbour the leptospires. Humans may be directly infected from animal urine or indirectly by contact with soil or water that is contaminated with urine from infected animals. Infected humans can shed leptospires in urine for up to 11 months, infected cows for 3.5 months, infected dogs for 4 years, and infected rodents possibly for their entire lifetime.
The organisms enter the host through mucous membranes or abraded skin. The incubation period ranges from 5 to 14 days.
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This question is part of the following fields:
- Microbiology
- Principles Of Microbiology
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Question 10
Correct
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Which of the following is the most common cause of megaloblastic anaemia:
Your Answer: Vitamin B12 deficiency
Explanation:Megaloblastic anemia results from inhibition of DNA synthesis during red blood cell production. When DNA synthesis is impaired, the cell cycle cannot progress from the growth stage to the mitosis stage. This leads to continuing cell growth without division, which presents as macrocytosis, with an increase in mean corpuscular volume (MCV). The defect in red cell DNA synthesis is most often due to hypovitaminosis, specifically vitamin B12 deficiency or folate deficiency.
Folate is an essential vitamin found in most foods, especially liver, green vegetables and yeast. The normal daily diet contains 200 – 250 μg, of which about 50% is absorbed. Daily adult requirements are about 100 μg. Absorption of folate is principally from the duodenum and jejunum. Stores of folate are normally only adequate for 4 months and so features of deficiency may be apparent after this time. -
This question is part of the following fields:
- Haematology
- Pathology
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Question 11
Correct
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On which of the following types of receptors does loperamide act?
Your Answer: Opioid receptors
Explanation:Loperamide inhibits acetylcholine release from the myenteric plexus acts by action on opioid mu-receptors, and this then reduces bowel motility. The intestinal transit time is increased, thereby facilitating water reabsorption.
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This question is part of the following fields:
- Gastrointestinal
- Pharmacology
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Question 12
Correct
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All of the following statement are correct regarding endothelium derived nitric oxide except:
Your Answer: Nitric oxide production is inhibited by local mediators such as bradykinin, histamine and serotonin.
Explanation:Factors that elevate intracellular Ca2+ increase nitric oxide (NO) production by the endothelium included local mediators such as histamine and serotonin, bradykinin, and some neurotransmitters like substance P. NO production is also stimulated by increased flow (shear stress) and additionally activates prostacyclin synthesis. As a result of basal production of NO, there is continuous modulation of vascular resistance and as a result, there is increased production of nitric oxide acts which causes vasodilation. Platelet activation and thrombosis are inhibited by nitric oxide.
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This question is part of the following fields:
- Cardiovascular
- Physiology
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Question 13
Correct
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While on morning rounds in the medical ward, the attending physician asks a medical student about the differences between transudates and exudates and their causes. The student explains that a transudate is an excess fluid that leaks out of an intravascular compartment due to an imbalance between oncotic and hydrostatic pressures.
Which ONE of the following conditions will he mention as the cause of a transudate?Your Answer: Meig’s syndrome
Explanation:Transudative effusions are caused due to systemic causes leading to increased hydrostatic pressure or decreased oncotic pressure. These include:
1) Meig’s Syndrome (Ovarian tumour causing ascites and pleural effusion)
2) Congestive heart failure
3) Nephrotic Syndrome
4) Myxoedema
5) Cirrhosis
6) SarcoidosisAn exudate is caused by local inflammation and results from increased vascular permeability. Causes include:
1) Rheumatoid arthritis
2) Pneumonia leading to empyema
3) Malignancies
4) Pericarditis -
This question is part of the following fields:
- General Pathology
- Pathology
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Question 14
Incorrect
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An elderly man with chronic heart and lung disease develops Legionnaires' disease. Which of the following clinical features is NOT typical of Legionnaires' disease:
Your Answer: Haemoptysis
Correct Answer: Confusion
Explanation:Legionella pneumophilais a Gram negative bacterium that is found in natural water supplies and in the soil, transmitted predominantly via inhalation of aerosols generated from contaminated water (direct person-to-person spread of infected patients does not occur). It is the cause of Legionnaires’ disease. Outbreaks of Legionnaires’ disease have been linked to poorly maintained air conditioning systems, whirlpool spas and hot tubs.
The clinical features of the pneumonic form of Legionnaires’ disease include:
Mild flu-like prodrome for 1-3 days
Cough (usually non-productive and occurs in approximately 90%)
Pleuritic chest pain
Haemoptysis
Headache
Nausea, vomiting and diarrhoea
AnorexiaLegionella pneumophilainfections can be successfully treated with macrolide antibiotics, such as erythromycin, or quinolones, such as ciprofloxacin. Tetracyclines, such as doxycycline, can also be used.
The syndrome of inappropriate antidiuretic hormone secretion (SIADH) can occur with Legionnaires’ disease and will result in hyponatraemia as is seen in this case.
Legionella pneumophilainfections are resistant to amoxicillin but can be successfully treated with macrolide antibiotics, such as erythromycin, or quinolones, such as ciprofloxacin. Tetracyclines, such as doxycycline, can also be used. The majority of cases of Legionnaires’ disease are caused by Legionella pneumophila, however many other species of Legionella have been identified.
Legionella longbeachae is another less commonly encountered species that has also been implicated in outbreaks. It is predominantly found in soil and potting compost, and has caused outbreaks of Pontiac fever, the non-respiratory and less severe variant of Legionnaires’ disease. -
This question is part of the following fields:
- Microbiology
- Pathogens
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Question 15
Incorrect
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Regarding the factor V Leiden gene mutation, which of the following best describes the clinical effect:
Your Answer: It results in deficiency of factor V.
Correct Answer: It results in increased levels of activated factor V.
Explanation:Factor V Leiden gene mutation is the most common inherited cause of an increased risk of venous thrombosis. Activated protein C normally breaks down activated factor V and so should slow the clotting reaction and prolong the APTT, but a mutation in the factor V gene makes factor V less susceptible to cleavage by activated protein C, resulting in increased levels of activated factor V.Heterozygotes for factor V Leiden are at an approximately five- to eight- fold increased risk of venous thrombosis compared to the general population (but only 10% of carriers will develop thrombosis in their lifetime). Homozygotes have a 30 – 140-fold increased risk. The incidence of factor V Leiden in patients with venous thrombosis is approximately 20 – 40%. It does not increase the risk of arterial thrombosis.
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This question is part of the following fields:
- Haematology
- Pathology
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Question 16
Correct
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Regarding cardiac excitation-contraction coupling, which of the following statements is CORRECT:
Your Answer: In relaxation, Ca 2+ is transported out of the cell using energy from a Na + gradient.
Explanation:During the AP plateau, Ca2+enters the cell and activates Ca2+sensitive Ca2+release channels in the sarcoplasmic reticulum allowing stored Ca2+to flood into the cytosol; this is called Ca2+-induced Ca2+release. In relaxation, about 80% of Ca2+is rapidly pumped back into the SR (sequestered) by Ca2+ATPase pumps. The Ca2+that entered the cell during the AP is transported out of the cell primarily by the Na+/Ca2+exchanger in the membrane which pumps one Ca2+ion out in exchange for three Na+ions in, using the Na+electrochemical gradient as an energy source. Increased heart rate increases the force of contraction in a stepwise fashion as intracellular [Ca2+] increases cumulatively over several beats; this is the Treppe effect. Factors that affect intracellular [Ca2+] and hence cardiac contractility are called inotropes.
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This question is part of the following fields:
- Cardiovascular
- Physiology
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Question 17
Correct
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A patient with diplopia is found to have eye deviation downwards and outwards. The likely nerves that are affected are:
Your Answer: Oculomotor nerve
Explanation:The results of an oculomotor (CN III) nerve palsy are a depressed and abducted (down and out) eye, ptosis, diplopia, and a fixed and dilated pupil.
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This question is part of the following fields:
- Anatomy
- Cranial Nerve Lesions
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Question 18
Incorrect
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C5 - C9 deficiency increases susceptibility to infection with which of the following:
Your Answer: Encapsulated bacteria
Correct Answer: Neisseria spp.
Explanation:If the complement sequence is completed, an active phospholipase (the membrane attack complex, MAC) is produced, which punches holes in the cell membrane and causes cell lysis. Because the MAC appears to be the sole means to destroy the Neisseria family of bacteria, C5 – C9 deficiency increases susceptibility to Neisseria infections.
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This question is part of the following fields:
- Immune Responses
- Pathology
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Question 19
Correct
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A thyroid function test is done for a 55-year-old woman with non-specific symptoms, the results are shown below:
TSH = 5.2
Free T4 is normal
Free T3 is normal
The most likely diagnosis in this patient is?
Your Answer: Subclinical hypothyroidism
Explanation:Hypothyroidism is diagnosed using the results of thyroid function tests (TFTs).
In the early stages of the disease, the earliest biochemical change noticed is a rise in thyroid-stimulating hormone (TSH) levels. Free triiodothyronine (T3) and thyroxine (T4) levels are usually normal.
In primary hypothyroidism, the serum TSH level is usually greater than 10 mU/L, and free T4 levels are below the reference range.
Subclinical hypothyroidism is diagnosed when the serum TSH level is above the reference range, and the free T4 levels are within the reference range. The test should, however, be repeated after 3-6 months to exclude transient causes of raised TSH.
In summary, how to interpret TFTs in cases of suspected hypothyroidism is shown below:
Subclinical hypothyroidism
TSH is raised
Free T4 is normal
Free T3 is normalPrimary hypothyroidism
TSH is raised
Free T4 is lowered
Free T3 is lowered or normalSecondary hypothyroidism
TSH is lowered or normal
Free T4 is lowered
Free T3 is lowered or normal -
This question is part of the following fields:
- Endocrine Physiology
- Physiology
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Question 20
Correct
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The following statements about leukotrienes as chemical mediators of the acute inflammatory response are all true EXCEPT?
Your Answer: They decrease vascular permeability
Explanation:Leukotrienes increases (not decrease) vascular permeability during acute inflammation.
All the other statements are correct
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This question is part of the following fields:
- General Pathology
- Pathology
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Question 21
Correct
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A 57-year-old woman receives vitamin B12 injections following a gastrectomy.
Which of the following cell types, if absent, is responsible for her vitamin B12 deficiency?Your Answer: Parietal cells
Explanation:Intrinsic factor, produced by the parietal cells of the stomach, is essential for the absorption of vitamin B12 from the terminal ileum.
After a gastrectomy, the absorption of vitamin B12 is markedly reduced, and a deficiency will occur. -
This question is part of the following fields:
- Gastrointestinal Physiology
- Physiology
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Question 22
Incorrect
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Bendoflumethiazide may cause all of the following electrolyte imbalances EXCEPT for:
Your Answer: Hypomagnesaemia
Correct Answer: Hypocalcaemia
Explanation:Common side effects of thiazide diuretics include:
Excessive diuresis, postural hypotension, dehydration, renal impairment
Acid-base and electrolyte imbalance
Hypokalaemia, hyponatraemia, hypomagnesaemia, hypercalcaemia, hypochloraemic alkalosis
Metabolic imbalance
Hyperuricaemia and gout
Impaired glucose tolerance and hyperglycaemia
Altered plasma-lipid concentrations
Mild gastrointestinal disturbances -
This question is part of the following fields:
- Cardiovascular
- Pharmacology
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Question 23
Correct
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Question 24
Correct
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Which one of the listed cells are typically found in a granuloma?
Your Answer: Epithelioid cells
Explanation:Typically, a granuloma has Langhan’s cells (large multinucleated cells) surrounded by epithelioid cell aggregates, T lymphocytes and fibroblasts.
Antigen presenting monocytic cells are found in the skin are known as Langerhan’s cells.
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This question is part of the following fields:
- General Pathology
- Pathology
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Question 25
Correct
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A 54-year-old man who is acutely unwell has his blood sent for test and the results come back with a CRP of 115.
Which of these statements about C-reactive protein is FALSE?
Your Answer: It is produced in the bone marrow
Explanation:C-reactive protein(CRP) is synthesized in the liver in response to increased interleukin-6 (IL-6) secretion by macrophages and T-cells.
Some conditions that cause CRP levels to a rise include: bacterial infection, fungal infection, severe trauma, autoimmune disease, Organ tissue necrosis, malignancy and surgery.It is useful in the clinical setting as a marker of inflammatory activity and can be used to monitor infections.
CRP levels start to rise 4-6 hours after an inflammatory trigger and reaches peak levels at 36-50 hours.
In the absence of a disease process, the normal plasma concentration is less than 5 mg/l.
CRP is useful for monitoring inflammatory conditions (e.g. rheumatoid arthritis and malignancy), can be used as a prognostic marker in acute pancreatitis, and serial measurement can be used to recognize the onset of nosocomial infections in the intensive care settling.
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This question is part of the following fields:
- General Pathology
- Pathology
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Question 26
Incorrect
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In the Kaplan-Meier plot, which of the following labels should be applied to the X-axis?
Your Answer: Number of study participants
Correct Answer: Time in years
Explanation:Kaplan-Meier estimate is one of the best options to be used to measure the fraction of subjects living for a certain amount of time after treatment. In clinical trials or community trials, the effect of an intervention is assessed by measuring the number of subjects survived or saved after that intervention over a period of time. The time starting from a defined point to the occurrence of a given event, for example death, is called as survival time and the analysis of group data as survival analysis.
The graph plotted between estimated survival probabilities/estimated survival percentages (on Y axis) and time past after entry into the study (on X axis) consists of horizontal and vertical lines.
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This question is part of the following fields:
- Evidence Based Medicine
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Question 27
Correct
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Which of the following tracts must be affected if a patient presents with decreased pain and temperature sensation in both lower extremities?
Your Answer: The lateral spinothalamic tract
Explanation:The main function of the spinothalamic tract is to carry pain and temperature via the lateral part of the pathway and crude touch via the anterior part. The spinothalamic tract pathway is an imperative sensory pathway in human survival because it enables one to move away from noxious stimuli by carrying pain and temperature information from the skin to the thalamus where it is processed and transmitted to the primary sensory cortex. The primary sensory cortex communicates with the primary motor cortex, which lies close to it, to generate rapid movement in response to potentially harmful stimuli. Furthermore, the spinothalamic tract has a role in responding to pruritogens, causing us to itch. Interestingly, itching suppresses the spinothalamic tract neuron response to the histamine effect.
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This question is part of the following fields:
- Anatomy
- Central Nervous System
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Question 28
Incorrect
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What is the interquartile range for these numbers: 11, 4, 6, 8, 3, 10, 8, 10, 4, 12, 31?
Your Answer: 10
Correct Answer: 7
Explanation:We obtain 3, 4, 4, 6, 8, 8, 10, 11, 12, and 31, and sample size (n) = 11 when we order the data. [(n+1)/2] = median 6th value = (11+1)/2 = [(n+1)/4] represents the bottom (first) quartile. (3rd value = 4th value = (11 + 1)/4 3[(n+1)/4] for the top (third) quartile 3[(11 + 1)/4] = 9th value = 11th value = 11th value = 11th value = 11th value = 11th value = 11th value = 11th value = 11th The difference between the upper and lower quartiles is the interquartile range, which is equal to 11 minus 4 = 7.
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This question is part of the following fields:
- Evidence Based Medicine
- Statistics
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Question 29
Incorrect
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A 6-year-old child with a few itchy honey crusted sores on her left cheek is brought in by her mother. Following a thorough examination of the child, you diagnose impetigo and recommend a course of topical fusidic acid.
Fusidic acid's mode of action is which of the following?Your Answer: Forming pores that disrupt the cell membrane
Correct Answer: Inhibition of protein synthesis
Explanation:By binding EF-G-GDP, fusidic acid prevents both peptide translocation and ribosome disassembly, which slows protein synthesis. Because it has a novel structure and mechanism of action, it is unlikely to cause cross-resistance with existing antibiotics.
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This question is part of the following fields:
- Infections
- Pharmacology
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Question 30
Incorrect
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A patient presents with a fever, headache and neck stiffness. A CSF sample of someone with meningococcal meningitis typically shows:
Your Answer: Gram-negative diplococci
Correct Answer: All of the above
Explanation:CSF analysis typically shows:
cloudy turbid appearance
raised WCC – predominantly neutrophils
high protein
low glucose (typically < 40% of serum glucose)
Gram-negative diplococci seen under microscopy -
This question is part of the following fields:
- Microbiology
- Pathogens
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Question 31
Incorrect
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A 23-year-old male is referred to your haematology clinic after an acute attack of haemolytic anaemia. He was diagnosed with glucose-6-phosphate dehydrogenase deficiency ten years ago.
Which ONE of the following options is FALSE with regards to this disorder?Your Answer: Most individuals with G6PD deficiency are asymptomatic
Correct Answer: Acute haemolysis can be triggered by cephalosporin antibiotics
Explanation:Glucose-6-phosphate dehydrogenase deficiency is an X-linked recessive disorder in which there is a deficiency of the enzyme G6PD. This causes instability of red blood cell membranes under oxidative stress leading to haemolysis.
Triggers include:
1) Fava beans
2) Sulphonamides
3) Primaquine
4) Anti-TB drugs
5) InfectionsMost individuals will be asymptomatic until exposed to one of the triggers listed above. It is the commonest human enzyme defect and affects males more than females because of the X-linked inheritance pattern. The use of penicillins and cephalosporins is generally safe.
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This question is part of the following fields:
- Haematology
- Pathology
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Question 32
Correct
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A possible diagnosis of Cushing's illness is being investigated in an overweight patient with resistant hypertension. A CRH (corticotropin-releasing hormone) test is scheduled.
Which of the following statements about corticotropin-releasing hormone is correct?Your Answer: It is produced by cells within the paraventricular nucleus of the hypothalamus
Explanation:Corticotropin-releasing hormone (CRH) is a neurotransmitter and peptide hormone. It is generated by cells in the hypothalamic paraventricular nucleus (PVN) and released into the hypothalamo-hypophyseal portal system at the median eminence through neurosecretory terminals of these neurons. Stress causes the release of CRH.
The CRH is carried to the anterior pituitary through the hypothalamo-hypophyseal portal system, where it activates corticotrophs to release adrenocorticotropic hormone (ACTH). Cortisol, glucocorticoids, mineralocorticoids, and DHEA are all produced in response to ACTH.
Excessive CRH production causes the size and quantity of corticotrophs in the anterior pituitary to expand, which can lead to the creation of a corticotrope tumour that generates too much ACTH.
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This question is part of the following fields:
- Endocrine Physiology
- Physiology
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Question 33
Incorrect
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A 21-year-old student presents with fever, headache, malaise, fatigue, and muscle aches after returning from a trip to India. A diagnosis of malaria was suspected.
Which of the following statements is considered correct regarding malaria?Your Answer: Diagnosis is normally by ELISA testing
Correct Answer: Haemoglobinuria and renal failure following treatment is suggestive of Plasmodium falciparum
Explanation:Malaria results from infection with single-celled parasites belonging to the Plasmodium genus. Five species of Plasmodium are known to cause disease in humans: P. falciparum, P. vivax, P. ovale, P. malariae, and P. knowlesi.
Chloroquine remains the mainstay of treatment for uncomplicated vivax malaria.
The female Anopheles mosquito serves as the biologic vector and definitive host.
A complication of infection with P. falciparum is blackwater fever, a condition characterized by haemoglobinuria.
Plasmodium ovale has the longest incubation period, which can be up to 40 days. Plasmodium falciparum has a shorter incubation period of 7-14 days.
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This question is part of the following fields:
- Microbiology
- Specific Pathogen Groups
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Question 34
Correct
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Which of the following is most likely to cause a bitemporal hemianopia:
Your Answer: Pituitary adenoma
Explanation:A bitemporal hemianopia is most likely due to compression at the optic chiasm. This may be caused by pituitary tumour, craniopharyngioma, meningioma, optic glioma or aneurysm of the internal carotid artery. A posterior cerebral stroke will most likely result in a contralateral homonymous hemianopia with macular sparing.
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This question is part of the following fields:
- Anatomy
- Central Nervous System
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Question 35
Correct
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A young farmer who is caught under farm machinery and suffering from a major crush injury is taken to the emergency department and requires a quick induction sequence. In this type of injury, which of the following anaesthetic medicines should be avoided?
Your Answer: Suxamethonium
Explanation:Suxamethonium is a neuromuscular blocker. It is contraindicated in patients who have experienced massive trauma, hyperkalemic, or burn injuries.
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This question is part of the following fields:
- Anaesthesia
- Pharmacology
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Question 36
Correct
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Regarding inhaled corticosteroids, which of the following statements is INCORRECT:
Your Answer: Lower doses of inhaled corticosteroids may be required in smokers.
Explanation:Current and previous smoking reduces the effectiveness of inhaled corticosteroids and higher doses may be necessary.
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This question is part of the following fields:
- Pharmacology
- Respiratory
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Question 37
Correct
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Which lobe of the prostate gland is most commonly affected in benign prostatic hypertrophy?
Your Answer: Median
Explanation:Benign enlargement of the prostate is common in men older than 50 years. The cause is possibly an imbalance in the hormonal control of the gland. The median lobe of the gland enlarges upward and encroaches within the sphincter vesicae, located at the neck of the bladder. The leakage of urine into the prostatic urethra causes an intense reflex desire to micturate. The enlargement of the median and lateral lobes of the gland produces elongation and lateral compression and distortion of the urethra so that the patient experiences difficulty in passing urine and the stream is weak. Back-pressure effects on the ureters and both kidneys are a common complication. The enlargement of the uvula vesicae (owing to the enlarged median lobe) results in the formation of a pouch of stagnant urine behind the urethral orifice within the bladder. The stagnant urine frequently becomes infected, and the inflamed bladder (cystitis) adds to the patient’s symptoms.
In all operations on the prostate, the surgeon regards the prostatic venous plexus with respect. The veins have thin walls, are valveless, and are drained by several large trunks directly into the internal iliac veins. Damage to these veins can result in a severe haemorrhage.
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This question is part of the following fields:
- Abdomen And Pelvis
- Anatomy
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Question 38
Correct
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All of the following are actions of insulin except:
Your Answer: Increased gluconeogenesis
Explanation:Major Actions of Insulin:
↑ Glucose uptake into cells
↑ Glycogenesis
↓ Glycogenolysis
↓ Gluconeogenesis
↑ Protein synthesis
↓ Protein degradation
↑ Fat deposition
↓ Lipolysis
↓ Ketoacid production
↑ K+ uptake into cellsMajor Actions of Glucagon:
↓ Glycogenesis
↑ Glycogenolysis
↑ Gluconeogenesis
↓ Fatty acid synthesis
↑ Lipolysis
↑ Ketoacid production -
This question is part of the following fields:
- Endocrine
- Physiology
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Question 39
Correct
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Which of the following microbes attaches to host cells by its haemagglutinin antigen:
Your Answer: Influenza virus
Explanation:Hemagglutinin (HA) or Haemagglutinin (BE) is an antigenic glycoprotein found on the surface of the influenza viruses. It is responsible for binding the virus to the cell that is being infected. The name hemagglutinin comes from the protein’s ability to cause red blood cells (erythrocytes) to clump together (agglutinate) in vitro.
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This question is part of the following fields:
- Microbiology
- Principles
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Question 40
Correct
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A 23-year-old has a known diagnosis of HIV. Blood is sent to the laboratory for tests.
AIDS be diagnosed at a CD4 counts below?Your Answer: 200 cells/mm 3
Explanation:A normal CD4 count ranges from 500-1000 cells/mm3.
At CD4 count of less than 350 cells/mm3 treatment with anti-retroviral therapy should be considered.
At a CD4 count of >200 cells/mm3 AIDS is diagnosed.
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This question is part of the following fields:
- Microbiology
- Specific Pathogen Groups
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Question 41
Incorrect
-
An ambulance transports a 72-year-old woman to the Emergency Department. She is confused, has been vomiting and having stomach pains. Digoxin is one of her medications.
Which of the following claims about digoxin is correct?Your Answer: It is the first-line drug in the treatment of persistent and permanent atrial fibrillation
Correct Answer: Therapeutic plasma levels are between 1.0-1.5 nmol/l
Explanation:Digoxin is a cardiac glycoside that is used to treat atrial fibrillation and flutter, as well as congestive heart failure. In cardiac myocytes, it works by inhibiting the membrane Na/K ATPase. Through Na/Ca exchange, this raises intracellular sodium concentration and indirectly increases intracellular calcium availability. Increased intracellular calcium levels have both a positive inotropic and negative chronotropic effect.
Digoxin therapeutic plasma levels are typically between 1.0 and 1.5 nmol/l, though higher concentrations may be required, and the value varies between laboratories. At concentrations greater than 2 nmol/l, the risk of toxicity increases dramatically.
In patients with normal renal function, digoxin has a long plasma half-life of 36 to 48 hours. This can take up to 5 days in patients with impaired renal function.
Hypokalaemia, rather than hyperkalaemia, has been shown to increase the risk of digoxin toxicity.
In the treatment of persistent and permanent atrial fibrillation, digoxin is no longer widely used. Beta-blockers, also known as rate-limiting calcium channel blockers, are now the first-line treatment for this condition.
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This question is part of the following fields:
- Cardiovascular Pharmacology
- Pharmacology
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Question 42
Correct
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Question 43
Correct
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A 17-year-old type I diabetic patient presents with abdominal pain and vomiting. Measurement of her blood glucose level is done and found to be grossly elevated. She is diagnosed with diabetic ketoacidosis. A fixed rate insulin infusion is given as part of her treatment.
Which of these is an action of insulin?Your Answer: Stimulates lipogenesis
Explanation:Insulin is an anabolic hormone. Its actions can be broadly divided into:
Lipid metabolism
Protein metabolism and
Carbohydrate metabolismFor lipid metabolism, insulin:
Stimulates lipogenesis
Inhibits lipolysis by lipaseFor carbohydrate metabolism, insulin:
Decreases gluconeogenesis
Stimulates glycolysis
Promotes glucose uptake in muscle and adipose tissue
Promotes glycogen storage
Increases glycogenesis
Decreases glycogenolysisProtein metabolism:
Stimulates protein synthesis
Accelerates net formation of protein
Stimulates amino acid uptake
Inhibits protein degradation
Inhibits amino acid conversion to glucose -
This question is part of the following fields:
- Endocrine Physiology
- Physiology
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Question 44
Correct
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Oedema can occur as a result of any of the following WITH THE EXCEPTION OF:
Your Answer: Increased interstitial hydrostatic pressure
Explanation:Oedema is defined as a palpable swelling produced by the expansion of the interstitial fluid volume. A variety of clinical conditions are associated with the development of oedema, including heart failure, cirrhosis, and nephrotic syndrome. The development of oedema requires an alteration in capillary dynamics in a direction that favours an increase in net filtration and also inadequate removal of the additional filtered fluid by lymphatic drainage. Oedema may form in response to an elevation in capillary hydraulic pressure (which increases the delta hydraulic pressure) or increased capillary permeability, or it can be due to disruption of the endothelial glycocalyx, decreased interstitial compliance, a lower plasma oncotic pressure (which reduces the delta oncotic pressure), or a combination of these changes. Oedema can also be induced by lymphatic obstruction since the fluid that is normally filtered is not returned to the systemic circulation.
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This question is part of the following fields:
- Cardiovascular
- Physiology
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Question 45
Incorrect
-
One of your patients is in resuscitation and is suffering from kidney failure. The intensive care outreach team arrives to assess them and determines that a dopamine infusion is necessary.
Dopamine primarily acts on which of the following receptors at low doses?Your Answer: Beta-1 receptors
Correct Answer: Dopamine receptors
Explanation:Dopamine is a catecholamine that occurs naturally and is used to treat low cardiac output, septic shock, and renal failure. It is both adrenaline and noradrenaline’s immediate precursor.
Dopamine acts on D1 and D2 dopamine receptors in the renal, mesenteric, and coronary beds at low doses (1-5 g/kg/min). Dopamine causes a significant decrease in renal vascular resistance and an increase in renal blood flow at these doses. Within this dose range, it is also involved in central modulation of behaviour and movement.
Dopamine stimulates beta- and alpha-adrenergic receptors directly and indirectly at higher doses. Beta-stimulation predominates at a rate of 5-10 g/kg/min, resulting in a positive inotropic effect that increases cardiac output and coronary blood flow. Alpha-stimulation predominates at infusion rates greater than 15 g/kg/min, resulting in peripheral vasoconstriction and an increase in venous return and systolic blood pressure.
Below is a summary of the mechanisms and effects of various inotropic agents:
Inotrope
Mechanism
Effects
Adrenaline (epinephrine)
Beta-1 and -2 agonist at increasing doses;
Alpha-agonist at high doses
Increased cardiac output;
Vasoconstriction at higher doses
Noradrenaline (norepinephrine)
Mainly alpha-agonist;
Beta-1 and -2 agonist at increasing doses
Vasoconstriction;
Some increased cardiac output
Dopamine
Dopamine agonist at low doses;
Beta-1 and -2 agonist at increasing doses;
Alpha-agonist at high doses
Increased cardiac output;
Vasoconstriction at higher doses
Dobutamine
Mainly beta-1 agonist
Increased cardiac output -
This question is part of the following fields:
- Cardiovascular Pharmacology
- Pharmacology
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Question 46
Correct
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A 70-year old male is taken to the Emergency Room after suffering a traumatic fall while showering. Upon physical examination, the attending physician noted a hyperextended neck, 1/5 muscle strength in both upper extremities, 4/5 muscle strength in both lower extremities, and variable loss in sensation. The patient is placed in the wards for monitoring. For the next 24 hours, anuria is noted.
Which of the following spinal cord injuries is the most likely diagnosis?Your Answer: Central cord syndrome
Explanation:Central cord syndrome is the most common type of incomplete cord injury and almost always occurs due to a traumatic injury. It results in motor deficits that are worse in the upper extremities as compared to the lower extremities. It may also cause bladder dysfunction (retention) and variable sensory deficits below the level of injury.
The majority of these patients will be older and present with symptoms after a fall with hyperextension of their neck. On examination, patients will have more significant strength impairments in the upper extremities (especially the hands) compared to the lower extremities. Patients often complain of sensory deficits below the level of injury, but this is variable. Pain and temperature sensations are typically affected, but the sensation of light touch can also be impaired. The most common sensory deficits are in a cape-like distribution across their upper back and down their posterior upper extremities. They will often have neck pain at the site of spinal cord impingement.
Bladder dysfunction (most commonly urinary retention) and priapism can also be signs of upper motor neuron dysfunction. The sacral sensation is usually preserved, but the clinician should assess the rectal tone to evaluate the severity of the compression.
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This question is part of the following fields:
- Anatomy
- Central Nervous System
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Question 47
Correct
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Which of the following is NOT an adverse effect associated with statin therapy:
Your Answer: Aplastic anaemia
Explanation:Adverse effects of statins include:, Headache, Epistaxis, Gastrointestinal disorders (such as constipation, flatulence, dyspepsia, nausea, and diarrhoea), Musculoskeletal and connective tissue disorders (such as myalgia, arthralgia, pain in the extremity, muscle spasms, joint swelling, and back pain), Hyperglycaemia and diabetes, Myopathy and rhabdomyolysis, Interstitial lung disease and Hepatotoxicity
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This question is part of the following fields:
- Cardiovascular
- Pharmacology
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Question 48
Correct
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Regarding gastric motility and emptying, which of the following statements is CORRECT:
Your Answer: Gastric emptying is inhibited by the presence of the products of fat digestion in the duodenum.
Explanation:Gastric emptying is decreased by the presence of fats in the duodenum (by stimulating release of cholecystokinin). Mixing of the food with gastric secretions takes place in the distal body and antrum of the stomach where the muscularis externa layer is thicker. The stomach has an additional inner oblique smooth muscle layer (in addition to the inner circular layer and outer longitudinal layer). Gastric emptying is increased by a low gastric pH and decreased by a low duodenal pH.
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This question is part of the following fields:
- Gastrointestinal
- Physiology
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Question 49
Correct
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In a patient with an ongoing seizure, after what time period should treatment be commenced?
Your Answer: 5 minutes
Explanation:Immediate emergency care and treatment should be given to children, young people and adults who have prolonged or repeated convulsive seizures.
Prolonged seizures last 5 minutes or more.
Repeated seizures refer to 3 or more seizures in an hour. -
This question is part of the following fields:
- Central Nervous System
- Pharmacology
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Question 50
Correct
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Which of the following muscles acts as an extensor of the shoulder joint?
Your Answer: Teres major
Explanation:The glenohumeral joint possesses the capability of allowing an extreme range of motion in multiple planes.
Flexion – Defined as bringing the upper limb anterior in the sagittal plane. The usual range of motion is 180 degrees. The main flexors of the shoulder are the anterior deltoid, coracobrachialis, and pectoralis major. Biceps brachii also weakly assists in this action.
Extension—Defined as bringing the upper limb posterior in a sagittal plane. The normal range of motion is 45 to 60 degrees. The main extensors of the shoulder are the posterior deltoid, latissimus dorsi, and teres major.
Internal rotation—Defined as rotation toward the midline along a vertical axis. The normal range of motion is 70 to 90 degrees. The internal rotation muscles are the subscapularis, pectoralis major, latissimus dorsi, teres major, and the anterior aspect of the deltoid.
External rotation – Defined as rotation away from the midline along a vertical axis. The normal range of motion is 90 degrees. Primarily infraspinatus and teres minor are responsible for the motion.
Adduction – Defined as bringing the upper limb towards the midline in the coronal plane. Pectoralis major, latissimus dorsi, and teres major are the muscles primarily responsible for shoulder adduction.
Abduction – Defined as bringing the upper limb away from the midline in the coronal plane. The normal range of motion is 150 degrees. Due to the ability to differentiate several pathologies by the range of motion of the glenohumeral joint in this plane of motion, it is essential to understand how different muscles contribute to this action.
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This question is part of the following fields:
- Anatomy
- Upper Limb
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Question 51
Incorrect
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At rest, skeletal muscle accounts for between 15-20% of cardiac output and accounts for around 50% of body weight. This can increase to nearly 80% of cardiac output during exercise. Skeletal muscle circulation is highly controlled and has a number of specialized adaptations as a result of this high degree of disparity during exercise, in combination with the diversity in the size of skeletal muscle around the body.
What is the primary mechanism for boosting skeletal muscle blood flow during exercise?
Your Answer: Sympathetic stimulation
Correct Answer: Metabolic hyperaemia
Explanation:In skeletal muscle, blood flow is closely related to metabolic rate. Due to the contraction of precapillary sphincters, most capillaries are blocked off from the rest of the circulation at rest and are not perfused. This causes an increase in vascular tone and vessel constriction. As metabolic activity rises, this develops redundancy in the system, allowing it to cope with greater demand. During exercise, metabolic hyperaemia, which is induced by the release of K+, CO2, and adenosine, recruits capillaries. Sympathetic vasoconstriction in the active muscles is overridden by this. Simultaneously, blood flow in non-working muscles is restricted, preserving cardiac output. During exercise, muscle contractions pump blood through the venous system, raising the pressure differential between arterioles and venules and boosting blood flow via capillaries.
Capillary angiogenesis is evident when muscles are used repeatedly (e.g. endurance training). It is a long-term effect, not a quick fix for increased blood flow.
The local partial pressure of alveolar oxygen is the primary intrinsic control of pulmonary blood flow (pAO2). Low pAO2 promotes arteriole vasoconstriction and vice versa. The hypoxic pulmonary vasoconstriction (HPV) reflex allows blood flow to be diverted away from poorly ventilated alveoli and towards well-ventilated alveoli in order to maximize gaseous exchange.
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This question is part of the following fields:
- Cardiovascular Physiology
- Physiology
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Question 52
Correct
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By what mechanism does Vibrio cholerae causes diarrhoea?
Your Answer: Increases Cl- secretory channels in crypt cells
Explanation:Cholera is a severe diarrheal illness caused by the Vibrio cholerae bacteria infecting the bowel. Ingesting cholera-infected food or drink is the a way to contract the disease. In the intestinal crypt cells, the toxigenic bacterium Vibrio cholera activates adenylate cyclase and raises cyclic adenosine monophosphate (cAMP).
cAMP stimulates the Cl-secretory channels in crypt cells, resulting in the secretion of chloride with sodium ions and water. The toxin it produces causes the body to secrete massive amounts of water, resulting in diarrhoea and significant fluid and electrolyte loss.
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This question is part of the following fields:
- Gastrointestinal
- Physiology
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Question 53
Correct
-
Which of the following statements is true regarding the extensor pollicis longus?
Your Answer: It is innervated by the posterior interosseous nerve
Explanation:Extensor pollicis longus is part of the deep extensors of the forearm together with extensor pollicis brevis, abductor pollicis longus, extensor indicis and supinator muscles. It is located on the posterior aspect of forearm, extending from the middle third of the ulna, and adjacent interosseous membrane, to the distal phalanx of the thumb.
Extensor digitorum is innervated by posterior interosseous nerve which is a continuation of a deep branch of radial nerve (root value C7 and C8).
Extensor pollicis brevis receives its blood supply from the posterior interosseous artery and perforating branches of the anterior interosseous artery.
The main action of extensor pollicis longus is extension of the thumb at the metacarpophalangeal and interphalangeal joints. Extension at the metacarpophalangeal joint occurs in synergy with extensor pollicis brevis muscle. When the thumb reaches the full extension or abduction, extensor pollicis longus can also assist in adduction of the thumb.
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This question is part of the following fields:
- Anatomy
- Upper Limb
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Question 54
Correct
-
A 24 year old male sustained an insect bite and presents with a red hot arm and acute cellulitis has been diagnosed. The predominant white cells in this type of acute inflammation are:
Your Answer: Neutrophils
Explanation:Neutrophil polymorphs are the predominant type of white cells in an acute reaction. They pass between endothelial cell junctions to invade damaged tissue so that the effects of injury can be combated. Extravasation occurs with the movement of leukocytes out of the vessel lumen, and is achieved in five phases which are margination, ‘rolling’, adhesion, transmigration and chemotaxis.
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This question is part of the following fields:
- Inflammatory Responses
- Pathology
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Question 55
Correct
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Question 56
Correct
-
Thyroid cancer has spread to the regional lymph nodes of a patient as seen in a staging CT scan.
The lymph from the thyroid gland will drain directly to which of the following nodes?Your Answer: Deep lateral cervical lymph nodes
Explanation:Lymphatic drainage of the thyroid gland involves the lower deep cervical, prelaryngeal, pretracheal, and paratracheal nodes. The paratracheal and lower deep cervical nodes, specifically, receive lymphatic drainage from the isthmus and the inferior lateral lobes. The superior portions of the thyroid gland drain into the superior pretracheal and cervical nodes.
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This question is part of the following fields:
- Anatomy
- Head And Neck
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Question 57
Correct
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A 16-year old boy is brought to the emergency room after suffering a traffic accident. Upon examination, there is noted ipsilateral loss of proprioception and vibration, ipsilateral motor loss, and contralateral loss of pain and temperature sensation. A spinal cord injury is given as a diagnosis.
Which of the following is the most probable cause of this manifestation?Your Answer: Brown-Séquard syndrome
Explanation:Brown-Sequard Hemicord Syndrome consists of ipsilateral weakness (corticospinal tract) and loss of joint position and vibratory sense (posterior column), with contralateral loss of pain and temperature sense (spinothalamic tract) one or two levels below the lesion. Segmental signs, such as radicular pain, muscle atrophy, or loss of a deep tendon reflex, are unilateral. Partial forms are more common than the fully developed syndrome.
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This question is part of the following fields:
- Anatomy
- Central Nervous System
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Question 58
Correct
-
Insulin is a very important peptide hormone produced by the islets of Langerhans in the pancreas.
Insulin is synthesised by which of the following cell types within the islets of Langerhans? Select ONE answer only.Your Answer: Beta cells
Explanation:Insulin is produced by beta cells, located centrally within the islets of Langerhans, in the endocrine tissues of the pancreas. Insulin is a polypeptide hormone consisting of two short chains (A and B) linked by disulphide bonds. Proinsulin is synthesised as a single-chain peptide. Within storage granules, a connecting peptide (C peptide) is removed by proteases to yield insulin. Insulin release is stimulated initially during eating by the parasympathetic nervous system and gut hormones such as secretin, but most output is driven by the rise in plasma glucose concentration that occurs after a meal. The effects of insulin are mediated by the receptor tyrosine kinase.
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This question is part of the following fields:
- Endocrine Physiology
- Physiology
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Question 59
Correct
-
Regarding a cohort study, which of the following statements is INCORRECT:
Your Answer: It is useful for rare diseases.
Explanation:A cohort study is a longitudinal, prospective, observational study that follows a defined group (cohort) matched to unexposed controls for a set period of time and investigates the effect of exposure to a risk factor on a particular future outcome. The usual outcome measure is the relative risk (risk ratio). A large sample size is required for a rare outcome of interest so it is not useful for rare diseases.
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This question is part of the following fields:
- Evidence Based Medicine
- Study Methodology
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Question 60
Correct
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A 23-year-old student presents with a fever and sore throat. Upon physical examination, it was observed that he had bilaterally enlarged tonsils that are covered in large amounts of exudate. A diagnosis of tonsillitis was made.
The lymph from the tonsils will drain to which of the following nodes?Your Answer: Deep cervical lymph nodes
Explanation:The tonsils are collections of lymphatic tissue located within the pharynx. They collectively form a ringed arrangement, known as Waldeyer’s ring: pharyngeal tonsil, 2 tubal tonsils, 2 palatine tonsils, and the lingual tonsil.
Lymphatic fluid from the lingual tonsil drains into the jugulodigastric and deep cervical lymph nodes.
Lymphatic fluid from the pharyngeal tonsil drains into the retropharyngeal nodes (which empty into the deep cervical chain), and directly into deep cervical nodes within the parapharyngeal space.
The retropharyngeal and the deep cervical lymph nodes drain the tubal tonsils.
The palatine tonsils drain to the jugulodigastric node, a node of the deep cervical lymph nodes, located inferior to the angle of the mandible.
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This question is part of the following fields:
- Anatomy
- Head And Neck
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Question 61
Correct
-
A 59-year-old man presents with increased sweating, weight loss, and palpitations. A series of blood tests done found a very low TSH level and a diagnosis of hyperthyroidism is made.
What is the commonest cause of hyperthyroidism?
Your Answer: Graves’ disease
Explanation:Hyperthyroidism results from an excess of circulating thyroid hormones. It is commoner in women, and incidence increases with age.
Hyperthyroidism can be subclassified into:
Primary hyperthyroidism – the thyroid gland itself is affected
Secondary hyperthyroidism – the thyroid gland is stimulated by excessive circulating thyroid-stimulating hormone (TSH).Graves’ disease is the most common cause of hyperthyroidism (estimates are that it causes between 50 and 80% of all cases).
Although toxic multinodular goitre, thyroiditis,TSH-secreting pituitary adenoma and drug-induced hyperthyroidism also causes hyperthyroidism, the commonest cause is Graves’ disease.
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This question is part of the following fields:
- Endocrine Physiology
- Physiology
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Question 62
Correct
-
A 22-year-old woman comes in with an asthmatic flare. Salbutamol is her only regular medication.
What is the dosage per inhalation of a standard metered dose salbutamol inhaler?Your Answer: 100 micrograms
Explanation:The dose of a conventional metered dose inhaler is 100 micrograms per metered inhalation.
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This question is part of the following fields:
- Pharmacology
- Respiratory Pharmacology
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Question 63
Correct
-
A patient presents with a rash for a dermatological examination. A flat circumscribed area of discoloured skin measuring 0.7 cm in diameter is seen on examination.
What is the best description of this rash that you have found on examination?
Your Answer: Macule
Explanation:A macule is a flat, well circumscribed area of discoloured skin less than 1 cm in diameter with no changes in the thickness or texture of the skin.
A vesicle is a visible collection of clear fluid measuring less than 0.5 cm in diameter.
A papule is a solid, well circumscribed, skin elevation measuring less than 0.5 cm in diameter.
A nodule is a solid, well circumscribed, raised area that lies in or under the skin and measures greater than 0.5 cm in diameter. They are usually painless.
A plaque is a palpable skin lesion that is elevated and measures >1cm in diameter.
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This question is part of the following fields:
- General Pathology
- Pathology
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Question 64
Correct
-
A 27-year-old man presents with a laceration of his forearm that severed the nerve that innervates flexor carpi radialis.
Which of the following nerves has been damaged in this case? Select ONE answer only.Your Answer: The median nerve
Explanation:Flexor carpi radialis is innervated by the median nerve.
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This question is part of the following fields:
- Anatomy
- Upper Limb
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Question 65
Correct
-
An outbreak of acute pneumonia occurs in military recruits living in one barrack and only in those persons located near the air conditioner. Epidemiologic surveillance results in isolation of the causal organism from the patients and from the drip pans of the air conditioner. The organism is weakly Gram-negative. The most likely organism is:
Your Answer: Legionella pneumophila
Explanation:Legionella pneumophilais a Gram negative bacterium that is found in natural water supplies and in the soil, transmitted predominantly via inhalation of aerosols generated from contaminated water (direct person-to-person spread of infected patients does not occur). It is the cause of Legionnaires’ disease. Outbreaks of Legionnaires’ disease have been linked to poorly maintained air conditioning systems, whirlpool spas and hot tubs.
The clinical features of the pneumonic form of Legionnaires’ disease include:
Mild flu-like prodrome for 1-3 days
Cough (usually non-productive and occurs in approximately 90%)
Pleuritic chest pain
Haemoptysis
Headache
Nausea, vomiting and diarrhoea
Anorexia
Legionella pneumophilainfections can be successfully treated with macrolide antibiotics, such as erythromycin, or quinolones, such as ciprofloxacin. Tetracyclines, such as doxycycline, can also be used.
The syndrome of inappropriate antidiuretic hormone secretion (SIADH) can occur with Legionnaires’ disease and will result in hyponatraemia as is seen in this case.
Legionella pneumophilainfections are resistant to amoxicillin but can be successfully treated with macrolide antibiotics, such as erythromycin, or quinolones, such as ciprofloxacin. Tetracyclines, such as doxycycline, can also be used. The majority of cases of Legionnaires’ disease are caused by Legionella pneumophila, however many other species of Legionella have been identified.
Legionella longbeachae is another less commonly encountered species that has also been implicated in outbreaks. It is predominantly found in soil and potting compost, and has caused outbreaks of Pontiac fever, the non-respiratory and less severe variant of Legionnaires’ disease. -
This question is part of the following fields:
- Microbiology
- Pathogens
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Question 66
Correct
-
The following are all examples of type IV hypersensitivity EXCEPT for:
Your Answer: Extrinsic allergic alveolitis
Explanation:Examples of type IV reactions includes:
Contact dermatitis
Hashimoto’s thyroiditis
Primary biliary cholangitis
Tuberculin skin test (Mantoux test)
Chronic transplant rejection
Granulomatous inflammation (e.g. sarcoidosis, Crohn’s disease) -
This question is part of the following fields:
- Immune Responses
- Pathology
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Question 67
Correct
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Carbamazepine is indicated for all of the following EXCEPT for:
Your Answer: Myoclonic seizures
Explanation:Carbamazepine is a drug of choice for simple and complex focal seizures and is a first-line treatment option for generalised tonic-clonic seizures. It is also used in trigeminal neuralgia and diabetic neuropathy. Carbamazepine may exacerbate tonic, atonic, myoclonic and absence seizures and is therefore not recommended if these seizures are present.
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This question is part of the following fields:
- Central Nervous System
- Pharmacology
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Question 68
Correct
-
Liquefactive necrosis is most commonly seen in which of the following conditions:
Your Answer: Ischaemic stroke
Explanation:Liquefactive necrosis results in the loss of all cellular structure and the formation of a soft, semi-solid mass. This is commonly seen in the brain after a cerebral infarction.
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This question is part of the following fields:
- Inflammatory Responses
- Pathology
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Question 69
Incorrect
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An analytical study is conducted to compare the risk of stroke between Ticagrelor therapy and Warfarin therapy among patients with atrial fibrillation. The following is obtained from the study:
No. of patients who took Ticagrelor: 300
No. of patients who took Ticagrelor and suffered a stroke: 30
No. of patients who took Warfarin: 500
No. of patients who took Warfarin and suffered a stroke: 20
Compute for the absolute risk reduction of a stroke, with Warfarin as the standard of treatment.Your Answer: -0.04
Correct Answer: -0.06
Explanation:Absolute risk reduction (ARR) is computed as the difference between the absolute risk in the control group (ARC) and the absolute risk in the treatment group (ART).
Since Warfarin is the standard of treatment, Warfarin is considered as the control group.
ARR = ARC-ART
ARR = (20/500) – (30/300)
ARR = -0.06This means that there is increased risk of stroke in the treatment group, which is the Ticagrelor group.
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This question is part of the following fields:
- Evidence Based Medicine
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Question 70
Correct
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A 54-year-old man with a long history of poorly controlled hypertension complains of a headache and vision blurring today. In triage, his blood pressure is 210/192 mmHg. A CT head scan is scheduled to rule out the possibility of an intracranial haemorrhage. You make the diagnosis of hypertensive encephalopathy and rush the patient to reus to begin blood pressure-lowering treatment. He has a history of brittle asthma, for which he has been admitted to the hospital twice in the last year.
Which of the following is the patient's preferred drug treatment?Your Answer: 25% of the mean arterial pressure over the first hour
Explanation:End-organ damage (e.g. encephalopathy, intracranial haemorrhage, acute myocardial infarction or ischaemia, dissection, pulmonary oedema, nephropathy, eclampsia, papilledema, and/or angiopathic haemolytic anaemia) characterises a hypertensive emergency (also known as ‘accelerated hypertension’ or malignant hypertension’ It’s a life-threatening condition that necessitates rapid blood pressure reduction to avoid end-organ damage and a negative outcome.
Hypertensive encephalopathy is a syndrome that includes headaches, seizures, visual changes, and other neurologic symptoms in people who have high blood pressure. It is reversible if treated quickly, but it can progress to coma and death if not treated properly.
Any patient with suspected hypertensive encephalopathy should have an urgent CT scan to rule out an intracranial haemorrhage, as rapid blood pressure reduction could be dangerous in these circumstances.
The drug of choice is labetalol, which reduces blood pressure steadily and consistently without compromising cerebral blood flow.
An initial reduction of approximately 25% in mean arterial pressure (MAP) over an hour should be aimed for, followed by a further controlled MAP reduction over the next 24 hours. In patients who are unable to take beta-blockers, nicardipine can be used as a substitute. -
This question is part of the following fields:
- Cardiovascular Pharmacology
- Pharmacology
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Question 71
Correct
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Which of the following statements is correct with regards to Hodgkin's lymphoma?
Your Answer: Most patients present with painless asymmetrical lymphadenopathy, with cervical nodes involved most commonly.
Explanation:Lymphoma is a cancer of the lymphatic system, which is part of the body’s germ-fighting network. They are a group of diseases that are caused by malignant lymphocytes. These malignant cells accumulate in lymph nodes and other lymphoid tissue, giving rise to the characteristic clinical feature of lymphadenopathy.
They can be subdivided into Hodgkin lymphoma (HL) which are characterised by the presence of Reed-Sternberg cells, and non-Hodgkin lymphoma (NHL).
Characteristics of HL include:
1. can present at any age but is rare in children and has a peak incidence in young adults,
2. almost 2:1 male predominance.
3. presents with painless, asymmetrical, firm and discrete enlargement of superficial lymph nodes.
4. cervical node involvement in 60-70% of cases,
5. axillary node involvement in 10-15%
6. inguinal node involvement in 6-12%.
7. modest splenomegaly during the course of the disease in 50% of patients
8. may occasionally have liver enlargement
9. bone marrow failure involvement is unusual in early disease.
Approximately 85% of patients are cured, but the prognosis depends on age, stage and histology.
Two well‐known but rare symptoms in HL are alcohol‐induced pain and pruritus. -
This question is part of the following fields:
- Haematology
- Pathology
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Question 72
Correct
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In a ward round, you come across a patient's treatment chart prescribed an antibiotic to fight his infection. This antibiotic is an inhibitor of cell wall synthesis.
Which of the following antimicrobial drugs is prescribed to this patient?Your Answer: Benzylpenicillin
Explanation:Penicillins and cephalosporins are the major antibiotics that inhibit bacterial cell wall synthesis. They inactivate transpeptidases that help cross-link peptidoglycans in cell walls.
Isoniazid decreases the synthesis of mycolic acids in mycobacterium.
Clarithromycin binds to the 50S subunit of ribosomes and inhibits protein synthesis.
Metronidazole and the other 5-nitroimidazole agents inhibit nucleic acid synthesis by forming toxic free radical metabolites in the bacterial cell that damage DNA.
Tetracycline bind to 30S and prevent attachment of aminoacyl-tRNA.
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This question is part of the following fields:
- Infections
- Pharmacology
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Question 73
Correct
-
You are about to give an antimuscarinic agent to a 55 year-old male patient. Which of the following conditions will make you with stop the administration, since it is a contraindication to antimuscarinic agents?
Your Answer: Prostatic enlargement
Explanation:Antimuscarinic medications may impair the contractility of bladder smooth muscle, resulting in acute urine retention in men with BPH, and should be avoided or used with caution.
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This question is part of the following fields:
- Gastrointestinal
- Pharmacology
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Question 74
Incorrect
-
Giemsa-stained blood film microscopy is typically used for the diagnosis of which of the following:
Your Answer: Tuberculosis
Correct Answer: Malaria
Explanation:Giemsa-stained blood film microscopy can be used to identify malarial parasites.
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This question is part of the following fields:
- Microbiology
- Principles
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Question 75
Correct
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Question 76
Correct
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A 10-year-old girl that appears systemically well presents with a honey-crusted scab close to the corner of her mouth and states that the area is slightly itchy but not painful. The diagnosis given was impetigo.
What is most likely the mode of transmission of the causative agent of the said diagnosis?Your Answer: Direct contact
Explanation:Impetigo is a common pyoderma that is most often seen in children. Historically, most cases were caused by group A streptococci (GAS; Streptococcus pyogenes), although S. aureus has become the predominant pathogen over the last 15 years.
A bullous form of impetigo accounts for approximately 10% of cases. It is caused by strains of S. aureus that produce exfoliative toxins leading to the formation of bullae, which quickly rupture and form a transparent, light brown crust.
Impetigo is spread mainly by person-to-person contact; it is rapidly spread through direct transmission. The diagnosis of impetigo can be made from a Gram stain and culture of the vesicular contents.
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This question is part of the following fields:
- Microbiology
- Principles Of Microbiology
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Question 77
Correct
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A 39-year-old guy comes to the emergency room with a persistent nasal bleed. You suspect the bleeding is coming from Little's area based on your examination. Which of the blood vessels listed below is most likely to be involved:
Your Answer: Sphenopalatine and superior labial arteries
Explanation:The Kiesselbach plexus is a vascular network formed by five arteries that supply oxygenated blood to the nasal septum, which refers to the wall separating the right and left sides of the nose. The five arteries that form the Kiesselbach plexus: the sphenopalatine artery, which branches from the maxillary artery originating behind the jawbone; the anterior ethmoidal artery, which branches from the ophthalmic artery behind the eye; the posterior ethmoidal artery, which also branches from the ophthalmic artery; the septal branch of the superior labial artery, which is a branch of the facial artery supplying blood to all of the superficial features of the face; and finally, the greater palatine artery, which is a terminal branch of the maxillary artery.
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This question is part of the following fields:
- Anatomy
- Head And Neck
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Question 78
Correct
-
A 50-year-old man presents with signs and symptoms of an anaphylactic reaction. His GP had recently given him a new medication.
Which one of these is the most likely medication responsible for the drug-induced anaphylactic reaction?
Your Answer: Penicillin
Explanation:The most common cause of drug-induced anaphylaxis is penicillin.
The second commonest cause are NSAIDs. Other drugs associated with anaphylaxis are ACE inhibitors and aspirin.
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This question is part of the following fields:
- Infections
- Pharmacology
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Question 79
Correct
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A 28-year-old female arrives after taking an unknown chemical in excess. She is tired and her speech is slurred. The following are her observations and results:HR 118,BP 92/58,SaO2 96%
HR 118, 11/15 The following are the results of his arterial blood gas (ABG):
pH: 7.24pO 2 : 9.4kPa PCO2 : 3.3kPa HCO 3 -: 22 mmol/lNa + : 143 mmol/lCl – : 99 mmol/lLactate: 5 IU/l
Which of the following statements about this patient is TRUE?Your Answer: Her anion gap is elevated
Explanation:The interpretation of arterial blood gas (ABG) aids in the measurement of a patient’s pulmonary gas exchange and acid-base balance.
The normal values on an ABG vary a little depending on the analyser, but they are roughly as follows:
Variable
Range
pH
7.35 – 7.45
PaO2
10 – 14 kPa
PaCO2
4.5 – 6 kPa
HCO3-
22 – 26 mmol/l
Base excess
-2 – 2 mmol/lThe patient’s history indicates that she has taken an overdose in this case. Because her GCS is 11/15 and she can communicate with slurred speech, she is clearly managing her own airway, there is no current justification for intubation.
The following are the relevant ABG findings:
Hypoxia (mild)
pH has been lowered (acidaemia)
PCO2 levels are low.
bicarbonate in its natural state
Lactate levels have increasedThe anion gap represents the concentration of all the unmeasured anions in the plasma. It is the difference between the primary measured cations and the primary measured anions in the serum. It can be calculated using the following formula:
Anion gap = [Na+] – [Cl-] – [HCO3-]The reference range varies depending on the technique of measurement, but it is usually between 8 and 16 mmol/L.
The following formula can be used to compute her anion gap:
Anion gap = [143] – [99] – [22]
Anion gap = 22As a result, it is clear that she has a metabolic acidosis with an increased anion gap.
The following are some of the causes of type A and type B lactic acidosis:
Type A lactic acidosis
Type B lactic acidosis
Shock (including septic shock)
Left ventricular failure
Severe anaemia
Asphyxia
Cardiac arrest
CO poisoning
Respiratory failure
Severe asthma and COPD
Regional hypoperfusion
Renal failure
Liver failure
Sepsis (non-hypoxic sepsis)
Thiamine deficiency
Alcoholic ketoacidosis
Diabetic ketoacidosis
Cyanide poisoning
Methanol poisoning
Biguanide poisoning -
This question is part of the following fields:
- Physiology
- Renal Physiology
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Question 80
Correct
-
Which of the following statements is true regarding a pleural aspiration?
Your Answer: The needle should be inserted just above the upper border of the chosen rib
Explanation:Pleural aspiration describes a procedure whereby pleural fluid or air may be aspirated via a system inserted temporarily into the pleural space. This may be for diagnostic purposes (usually removing 20–50 ml fluid) or therapeutic to relieve symptoms. In the literature it is varyingly called thoracocentesis, thoracentesis or pleural aspiration.
In determining the correct patient position and site of insertion, it is important for the operator to be aware of the normal anatomy of the thorax and the pathology of the patient. Patient position is dependent on the operator preference and the site of the pathology. In the case of a posterior lying locule, this may be specific to the image-guided spot where fluid is most likely to be obtained. In most circumstances, however, the site of insertion of the needle is either in the triangle of safety or the second intercostal space in the midclavicular line. The patient may therefore either sit upright leaning forward with arms elevated but resting on a table or bed, thereby exposing the axilla, or lying on a bed in a position. The needle is inserted in the space just above the chosen rib to avoid damaging the neurovascular bundle. It is common practice to insert the needle more posteriorly for a pleural aspiration, but it should be noted that the neurovascular bundle may not be covered by the lower flange of the rib in this position and a more lateral or anterior site of insertion is considered safer.
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This question is part of the following fields:
- Anatomy
- Thorax
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Question 81
Correct
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Which of the following acts to inhibit antidiuretic hormone (ADH) release from the posterior pituitary:
Your Answer: Atrial natriuretic peptide
Explanation:ADH release is inhibited by low plasma osmolality, alcohol, caffeine, glucocorticoids and atrial natriuretic peptide (ANP).
ADH release is stimulated primarily by raised plasma osmolality detected by osmoreceptors in the anterior hypothalamus. Other factors that increase ADH release include: extracellular fluid volume depletion, angiotensin II, nausea, pain, stress, exercise, emotion, hypoglycaemia.
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This question is part of the following fields:
- Endocrine
- Physiology
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Question 82
Correct
-
A patient with rash is examined. He has some redness of the skin that blanches when finger pressure is applied.
What is the best description of this rash that you have found on examination?Your Answer: Erythema
Explanation:Erythema is redness of the skin or mucous membranes caused by hyperaemia of superficial capillaries caused by skin injury, infection or inflammation. Erythema blanches when pressure is applied whereas ecchymosis, purpura and petechiae do not.
Ecchymosis are discolouration of the skin or mucous membranes caused by extravasation of blood. They are usually red or purple in colour and measure greater than 1 cm in diameter and do not blanch on applying pressure.
A macule is a flat, well circumscribed area of discoloured skin less than 1 cm in diameter with no changes in the thickness or texture of the skin.
Petechiae are discolouration of the skin measuring less than 3 mm in diameter
Purpura are discolouration of the skin measuring between 0.3 cm and 1 cm in diameter.
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This question is part of the following fields:
- General Pathology
- Pathology
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Question 83
Correct
-
Which of the following best describes digoxin:
Your Answer: A positive inotrope and negative chronotrope
Explanation:Digoxin is a cardiac glycoside used in the treatment of atrial fibrillation and flutter, and congestive cardiac failure. It acts by inhibiting the membrane Na/K ATPase in cardiac myocytes. This raises intracellular sodium concentration and increases intracellular calcium availability indirectly via Na/Ca exchange. The increase in intracellular calcium levels causes an increases the force of myocardial contraction (positive inotrope), and slows the heart rate (negative chronotrope).
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This question is part of the following fields:
- Cardiovascular
- Pharmacology
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Question 84
Correct
-
Which of the following is an action of glucagon:
Your Answer: Stimulates glycogenolysis
Explanation:Glucagon is a peptide hormone that is produced and secreted by alpha cells of the islets of Langerhans, which are located in the endocrine portion of the pancreas. The main physiological role of glucagon is to stimulate hepatic glucose output, thereby leading to increases in glycaemia. It provides the major counter-regulatory mechanism to insulin in maintaining glucose homeostasis.
Hypoglycaemia is the principal stimulus for the secretion of glucagon but may also be used as an antidote in beta-blocker overdose and in anaphylaxis in patients on beta-blockers that fail to respond to adrenaline.
Glucagon then causes:
Glycogenolysis
Gluconeogenesis
Lipolysis in adipose tissue
The secretion of glucagon is also stimulated by:
Adrenaline
Cholecystokinin
Arginine
Alanine
Acetylcholine
The secretion of glucagon is inhibited by:
Insulin
Somatostatin
Increased free fatty acids
Increased urea productionGlycolysis is the metabolic pathway that converts glucose into pyruvate. The free energy released by this process is used to form ATP and NADH. Glycolysis is inhibited by glucagon, and glycolysis and gluconeogenesis are reciprocally regulated so that when one cell pathway is activated, the other is inactive and vice versa.
Glucagon has a minor effect of enhancing lipolysis in adipose tissue. Lipolysis is the breakdown of lipids and involves the hydrolysis of triglycerides into glycerol and free fatty acids. It makes fatty acids available for oxidation.
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This question is part of the following fields:
- Endocrine
- Pharmacology
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Question 85
Correct
-
A 60-year-old man with insulin-controlled diabetes mellitus asks you about how his ability to drive is affected. He owns a car as well as a motorcycle.
Which of the following statements about driving with diabetes under insulin control is correct?Your Answer: He must monitor his blood glucose levels every 2 hours whilst driving
Explanation:The DVLA sends a detailed information sheet about their licence and driving to all drivers with diabetes mellitus. The primary danger of driving while diabetic is hypoglycaemia.
The DVLA must be notified of the following diabetic patients:
All of the drivers are on insulin. (Licenses are being reviewed more frequently.)
Those who are at high risk of hypoglycaemia and have had more than one episode of severe hypoglycaemia in the previous year. (Severe hypoglycaemia is defined as requiring the assistance of another person to manage.)
Those who are unaware of their hypoglycaemia
Anyone who has ever been in a car accident due to hypoglycaemia
Anyone with diabetic retinopathy who needs laser treatment (to both eyes or to a second eye if sight only in one eye)
Patients with diabetes complications that impair their ability to drive.To drive, drivers with insulin-treated diabetes must meet the following requirements:
They need to be aware of hypoglycaemia.
They must not have had more than one episode of hypoglycaemia in the previous 12 months that necessitated the assistance of another person.
They must check their blood glucose levels no later than 2 hours before the first journey.
While driving, they must check their blood glucose levels every two hours.
The visual acuity and visual field standards must be met.Any significant changes in their condition must be reported to the DVLA. Furthermore, on days when they are not driving, group 2 licence holders must test their blood glucose twice daily using a metre that can store three months’ worth of readings.
In addition to this advice, the DVLA also offers the following advice to diabetic patients:
When taking tablets that have the potential to cause hypoglycaemia (such as sulfonylureas and glinides), monitoring may be necessary if there has been more than one episode of severe hypoglycaemia.
Drivers must show good control and be able to recognise hypoglycaemia.
Verify that your vision meets the required standard.If a patient feels hypoglycaemic or has a blood glucose level of less than 4.0 mmol/L, they should not drive. Driving should not be resumed until blood glucose levels have returned to normal, which should take 45 minutes.
If there are any warning signs, patients should carry rapidly absorbed sugar in their vehicle and stop, turn off the ignition, and eat it.
If resuscitation is required, a card stating which medications they are taking should be carried.
If hypoglycaemia causes an accident, a diabetic driver may be charged with driving under the influence of drugs.
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This question is part of the following fields:
- Endocrine Pharmacology
- Pharmacology
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Question 86
Incorrect
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Regarding hypernatraemia, which of the following statements is INCORRECT:
Your Answer: Hypernatraemia with an actual increase in total body sodium is rare.
Correct Answer: In acute severe hypernatraemia, seizures and intracranial vascular haemorrhage can occur as a result of brain cell lysis.
Explanation:Acute severe hypernatraemia is a medical emergency and requires inpatient management in a high dependency setting. Seizures and intracranial vascular haemorrhage as a result of brain cell crenation can occur. The cause is most commonly excessive water loss and the key aspect of treatment is aggressive fluid replacement (typically with normal saline as this is relatively hypotonic). If urine osmolality is low, diabetes insipidus (DI )should be considered and a trial of synthetic ADH given. In patients with known DI, it is essential to ensure synthetic ADH is given parenterally and that close fluid balance is observed.
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This question is part of the following fields:
- Endocrine
- Physiology
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Question 87
Incorrect
-
Regarding linear relationships between two variables, what does a positive correlation coefficient indicate:
Your Answer: As one variable decreases, the other variable increases
Correct Answer: The two variables are directly proportional
Explanation:A positive correlation coefficient means that the two variables are directly proportional e.g. height and weight in healthy growing children.
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This question is part of the following fields:
- Evidence Based Medicine
- Statistics
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Question 88
Incorrect
-
All of the following statements are incorrect about insulin except:
Your Answer: Insulin release is stimulated initially during eating by the sympathetic nervous system.
Correct Answer: Proinsulin is cleaved into insulin and C peptide.
Explanation:Proinsulin is synthesised as a single-chain peptide. A connecting peptide (C peptide) within storage granules is removed by proteases to yield insulin.
Insulin:
1. is a polypeptide hormone consisting of two short chains (A and B) linked by disulphide bonds.
2. is produced by beta cells, located centrally within the islets of Langerhans, in the endocrine tissues of the pancreas.
3. release is stimulated initially during eating by the parasympathetic nervous system and gut hormones such as secretin. However, most output is driven by the rise in plasma glucose concentration that occurs after a meal.
4. effects are mediated by the receptor tyrosine kinase. -
This question is part of the following fields:
- Endocrine
- Physiology
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Question 89
Correct
-
Excessive gastric acid output is detected in a patient with a history of recurrent stomach ulcers. It's possible that the patient has Zollinger-Ellison syndrome.
Which of the following statements about stomach acid is correct?Your Answer: The proton pump located in the canalicular membrane is vital to its secretion
Explanation:The stomach produces gastric acid, which is a digesting fluid. The stomach secretes about 2-3 litres every day. It is involved in tissue breakdown, the conversion of pepsinogen to active pepsin, and the creation of soluble salts with calcium and iron, and has a pH range of 1.5-3.5. It also serves as an immune system by destroying microbes.
The following substances are found in gastric acid:
Water
Acid hydrochloride
Pepsinogen
mucous
Intrinsic factorThe parietal cells in the proximal 2/3 (body) of the stomach release gastric acid. The concentration of hydrogen ions in parietal cell secretions is 1-2 million times that of blood. Chloride is released against both a concentration and an electric gradient, and active transport is required for the parietal cell to produce acid.
The following is how stomach acid is secreted:
1. Gastric acid secretion is dependent on the H+/K+ ATPase (proton pump) situated in the canalicular membrane. The breakdown of water produces hydrogen ions within the parietal cell. The hydroxyl ions produced in this reaction mix quickly with carbon dioxide to generate bicarbonate ions. Carbonic anhydrase is the enzyme that catalyses this process.
2. In return for chloride, bicarbonate is carried out of the basolateral membrane. The ‘alkaline tide’ occurs when bicarbonate is released into the bloodstream, resulting in a modest rise in blood pH. The parietal cell’s intracellular pH is maintained by this procedure. Conductance channels carry chloride and potassium ions into the lumen of canaliculi.
3. Through the action of the proton pump, hydrogen ions are pushed out of the cell and into the lumen in exchange for potassium; potassium is thus efficiently recycled.
4. The canaliculi accumulate osmotically active hydrogen ions, which creates an osmotic gradient across the membrane, allowing water to diffuse outward.
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This question is part of the following fields:
- Gastrointestinal Physiology
- Physiology
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Question 90
Correct
-
A 30-year-old woman was involved in a road traffic accident and had a class I haemorrhage.
Which physiological parameter is consistent with a diagnosis of class I haemorrhage?
Your Answer: Increased pulse pressure
Explanation:There are 4 classes of haemorrhage. Classification is based on clinical signs and physiological parameters.
In CLASS I:Blood loss (ml) is < or = 750
Blood loss(% blood volume) < or = 15%
Pulse rate (bpm) is <100
Respiratory rate is 14-20
Urine output (ml/hr) is >30
Pulse pressure is normal or increased
Systolic BP is normal
CNS/mental status patient is slightly anxiousIn CLASS II:
Blood loss (ml) is 750 – 1500
Blood loss(% blood volume) is 15 – 30%
Pulse rate (bpm) is 100 – 120
Respiratory rate is 20-30
Urine output (ml/hr) is 20-30
Pulse pressure is decreased
Systolic BP is normal
CNS/mental status patient is mildly anxiousIn CLASS III:
Blood loss (ml) is 1500 – 2000
Blood loss(% blood volume) is 30- 40%
Pulse rate (bpm) is 120 – 140
Respiratory rate is 30-40
Urine output (ml/hr) is 5-15
Pulse pressure is decreased
Systolic BP is decreased
CNS/mental status patient is anxious, confusedIn CLASS IV:
Blood loss (ml) is >2000
Blood loss(% blood volume) is >40%
Pulse rate (bpm) is >140
Respiratory rate is >40
Urine output (ml/hr) is negligible
Pulse pressure is decreased
Systolic BP is decreased
CNS/mental status patient is confused, lethargic -
This question is part of the following fields:
- Cardiovascular Physiology
- Physiology
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Question 91
Correct
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Regarding the trachea, which of the following statements is INCORRECT:
Your Answer: A cricothyrotomy involves making an opening in the neck inferior to the cricoid cartilage.
Explanation:A cricothyrotomy involves making an opening in the median cricothyroid ligament (the medial part of the cricothyroid membrane), between the cricoid cartilage below and the thyroid cartilage above.
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This question is part of the following fields:
- Anatomy
- Head And Neck
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Question 92
Correct
-
Which of the following describes the site of a Meckel's diverticulum:
Your Answer: Ileum
Explanation:Meckel’s lies on the antimesenteric surface of the middle-to-distal ileum, approximately 2 feet proximal to the ileocaecal junction. It appears as a blind-ended tubular outpouching of bowel, about 2 inches long, occurring in about 2% of the population, and may contain two types of ectopic tissue (gastric and pancreatic). The rich blood supply to the diverticulum is provided by the superior mesenteric artery.Proximal to the major duodenal papilla the duodenum is supplied by the gastroduodenal artery (branch of the coeliac trunk) and distal to the major duodenal papilla it is supplied by the inferior pancreaticoduodenal artery (branch of superior mesenteric artery). The arterial supply to the jejunoileum is from the superior mesenteric artery.
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This question is part of the following fields:
- Abdomen
- Anatomy
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Question 93
Correct
-
Cardiac myocytes contract by excitation-contraction coupling, very much like skeletal myocytes. On the other hand, calcium-induced calcium release (CICR) is a mechanism that is unique to Cardiac myocytes. The influx of calcium ions (Ca 2+) into the cell causes a 'calcium spark,' which causes more ions to be released into the cytoplasm.
In CICR, which membrane protein in the sarcoplasmic reticulum is involved?Your Answer: Ryanodine receptor
Explanation:Cardiac myocytes contract by excitation-contraction coupling, just like skeletal myocytes. Heart myocytes, on the other hand, utilise a calcium-induced calcium release mechanism that is unique to cardiac muscle (CICR). The influx of calcium ions (Ca2+) into the cell causes a ‘calcium spark,’ which causes more ions to be released into the cytoplasm.
An influx of sodium ions induces an initial depolarisation, much as it does in skeletal muscle; however, in cardiac muscle, the inflow of Ca2+ sustains the depolarisation, allowing it to remain longer. Due to potassium ion (K+) inflow, CICR causes a plateau phase in which the cells remain depolarized for a short time before repolarizing. Skeletal muscle, on the other hand, repolarizes almost instantly.
The release of Ca2+ from the sarcoplasmic reticulum is required for calcium-induced calcium release (CICR). This is mostly accomplished by ryanodine receptors (RyR) on the sarcoplasmic reticulum membrane; Ca2+ binds to RyR, causing additional Ca2+ to be released.
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This question is part of the following fields:
- Basic Cellular Physiology
- Physiology
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Question 94
Correct
-
A 30-year-old man present to the ED with abdominal pain, nausea and vomiting. It has been present for the past two days.
Which of the following statements regarding diarrhoea and vomiting is true?
Your Answer: E.Coli can cause diarrhoea and renal failure
Explanation:Escherichia coli strain 0157 causes enterohaemorrhagic diarrhoea and can lead to renal failure, haemolytic anaemia and thrombocytopenia.
Norwalk virus is an RNA virus.
Although transmission of rotavirus is primarily through the faeco-oral route, airborne spread has been seen in some cases.
Cryptosporidium are protozoa with acid fast walls and are resistant to both chlorine treatment and conventional filtering methods.
There is no therapy effective in treating cryptosporidium diarrhoea as the protozoa is not susceptible to antibiotics.
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This question is part of the following fields:
- Microbiology
- Specific Pathogen Groups
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Question 95
Correct
-
Which of the following is NOT a typical effect caused by adrenaline:
Your Answer: Bronchoconstriction
Explanation:Actions of adrenaline:
Cardiovascular system
– Increased rate and force of cardiac contraction
– Vasoconstriction of vessels in skin, mucous membranes and splanchnic bed
– Vasodilation of skeletal muscle vessels
– Increased cardiac output and blood pressure
Respiratory system
– Bronchodilation
– Increased ventilation rate
Gastrointestinal system
– Smooth muscle relaxation
– Contraction of sphincters
– Metabolism
– Decreased insulin release
– Increased glucagon release
– Increased thermogenesis
– Increased glycolysis
– Increased lipolysis
Eye
– Pupillary dilation -
This question is part of the following fields:
- Endocrine
- Physiology
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Question 96
Correct
-
Regarding the abductor pollicis longus, which of the following statements is true?
Your Answer: It extends the thumb at the carpometacarpal joint
Explanation:Abductor pollicis longus is a muscle found in the posterior compartment of the forearm. It is one of the five deep extensors in the forearm, along with the supinator, extensor pollicis brevis, extensor pollicis longus and extensor indicis.
Abductor pollicis longus is innervated by the posterior interosseous nerve (C7, C8), which is a continuation of the deep branch of the radial nerve. The radial nerve is a branch of the posterior cord of the brachial plexus.
Blood supply to the abductor pollicis longus muscle comes from the interosseous branches of the ulnar artery.
Acting alone or with abductor pollicis brevis, abductor pollicis longus pulls the thumb away from the palm. More specifically, it produces (mid-) extension and abduction of the thumb at the first metacarpophalangeal joint. This action is seen in activities such as bowling and shovelling.
Working together with the long and short extensors of the thumb, the muscle also helps to fully extend the thumb at the metacarpophalangeal joint. This action is important for loosening the hand grip, for example, when letting go of objects previously being held. Abductor pollicis longus also helps to abduct the hand (radial deviation) at the radiocarpal joint.
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This question is part of the following fields:
- Anatomy
- Upper Limb
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Question 97
Correct
-
The triage nurse asks if you will prescribe a dose of codeine phosphate for a patient who is in a lot of pain. You discover that you are unable to prescribe it due to a contra-indication after evaluating the patient.
The use of codeine phosphate is contraindicated in which of the following situations?Your Answer: Age under 12 years
Explanation:Codeine phosphate is a mild opiate that can be used to treat mild to moderate pain when other pain relievers like paracetamol or ibuprofen have failed. It can also be used to treat diarrhoea and coughs that are dry or painful.
The use of all opioids is contraindicated for the following reasons:
Respiratory depression (acute)
Patients who are comatose
Head injury (opioid analgesics impair pupillary responses, which are crucial for neurological evaluation)
Intracranial pressure has risen (opioid analgesics interfere with pupillary responses vital for neurological assessment)
There’s a chance you’ll get paralytic ileus.The use of codeine phosphate is contraindicated in the following situations:
Because of the significant risk of respiratory side effects in children under the age of 12, it is not recommended for children under the age of 12.Patients of any age who have been identified as ultra-rapid codeine metabolizers (CYP2D6 ultra-rapid metabolizers)
Because codeine can pass through breast milk to the baby and because mothers’ ability to metabolise codeine varies greatly, it is especially dangerous in breastfeeding mothers.
If other painkillers, such as paracetamol or ibuprofen, fail to relieve acute moderate pain in children over the age of 12, codeine should be used. In children with obstructive sleep apnoea who received codeine after tonsillectomy or adenoidectomy, a significant risk of serious and life-threatening adverse reactions has been identified.
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This question is part of the following fields:
- CNS Pharmacology
- Pharmacology
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Question 98
Correct
-
When treating diabetic ketoacidosis (DKA), glucose should be given together with insulin as soon as the blood glucose concentration falls below 14 mmol/L in the form of:
Your Answer: 10% glucose intravenous infusion at a rate of 125 mL/hour
Explanation:In addition to the sodium chloride 0.9 percent infusion, glucose 10% should be given intravenously (into a large vein with a large-gauge needle) at a rate of 125 mL/hour once blood glucose concentration falls below 14 mmol/litre.
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This question is part of the following fields:
- Endocrine
- Pharmacology
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Question 99
Correct
-
Captopril should not be used if you have any of the following conditions:
Your Answer: Renal artery stenosis
Explanation:Contraindications indications of Captopril include:
– Bilateral renal artery stenosis
– Hypersensitivity to ACE inhibitors
– Anuria
– History of ACEI-induced angioedema
– Hereditary or idiopathic angioedema
– Co-administration of Neprilysin inhibitors (e.g., sacubitril) with ACE inhibitors may increase angioedema risk; do not administer ACE inhibitors within 36 hours of switching to or from sacubitril/valsartan.
If ACE inhibitors are used, they should be initiated only under specialist supervision and renal function should be monitored regularly. ACE inhibitors should also be used with particular caution in patients who may have undiagnosed and clinically silent renovascular disease. This includes patients with peripheral vascular disease or those with severe generalised atherosclerosis. -
This question is part of the following fields:
- Cardiovascular
- Pharmacology
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Question 100
Incorrect
SESSION STATS - PERFORMANCE PER SPECIALTY
