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Question 1
Incorrect
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Regarding Clostridium tetani, which of the following statements is CORRECT:
Your Answer: It has endotoxin-mediated effects.
Correct Answer: Metronidazole is usually the antibiotic of choice for tetanus infection.
Explanation:Clostridium tetani infection is predominantly derived from animal faeces and soil. Â Clostridium tetani has exotoxin-mediated effects, predominantly by tetanospasmin which inhibits the release of GABA at the presynaptic membrane throughout the central and peripheral nervous system. Metronidazole has overtaken penicillin as the antibiotic of choice for treatment of tetanus (together with surgical debridement, tetanus toxoid immunisation, and human tetanus immunoglobulin).
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This question is part of the following fields:
- Microbiology
- Pathogens
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Question 2
Incorrect
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A patient is sent in by her GP with suspected ectopic pregnancy. Tubal ectopic pregnancies occur most commonly in which part of the uterine tube:
Your Answer: Infundibulum
Correct Answer: Ampulla
Explanation:Ectopic pregnancy most commonly occurs in the ampulla (70% of cases).
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This question is part of the following fields:
- Abdomen
- Anatomy
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Question 3
Incorrect
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A 39-year-old woman is feeling unwell one week after a parathyroid surgery.
Which of the following stimulates release of parathyroid hormone (PTH)?Your Answer: Hypomagnesaemia
Correct Answer: Increased plasma phosphate concentration
Explanation:PTH is synthesised and released from the chief cells of the four parathyroid glands located behind the thyroid gland.
It is a polypeptide containing 84 amino acids and it controls free calcium in the body.The following stimuli causes release of PTH:
Increased plasma phosphate concentration
Decreased plasma calcium concentrationPTH release is inhibited by:
Normal or increased plasma calcium concentration
HypomagnesaemiaThe main actions of PTH are:
Increases plasma calcium concentration
Decreases plasma phosphate concentration
Increases osteoclastic activity (increasing calcium and phosphate resorption from bone)
Increases renal tubular reabsorption of calcium
Decreases renal phosphate reabsorption
Increases renal conversion of 25-hydroxycholecalciferol to 1,25-dihydroxycholecalciferol (via stimulation of 1-alpha hydroxylase)
Increases calcium and phosphate absorption in the small intestine (indirectly via increased 1,25-dihydroxycholecalciferol) -
This question is part of the following fields:
- Endocrine Physiology
- Physiology
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Question 4
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 5
Incorrect
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At rest, the left dome of the diaphragm normally reaches as high as which of the following:
Your Answer: Seventh intercostal space
Correct Answer: Fifth intercostal space
Explanation:At rest the right dome of the diaphragm lies slightly higher than the left; this is thought to be due to the position of the liver. In normal expiration, the normal upper limits of the superior margins are the fifth rib for the right dome, the fifth intercostal space for the left dome and the xiphoid process for the central tendon.
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This question is part of the following fields:
- Anatomy
- Thorax
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Question 6
Correct
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An elderly patient presents to ED following a fall after feeling light headed when standing up. You are reviewing his medication and note that he is taking a high dose of furosemide. Loop diuretics act primarily at which of the following sites in the nephron:
Your Answer: Thick ascending limb
Explanation:Loop diuretics inhibit the Na+/K+/2Cl- symporter on the luminal membrane in the thick ascending limb of the loop of Henle, thus preventing reabsorption of NaCl and water. These agents reduce reabsorption of Cl- and Na+ and increase Ca2+ excretion and loss of K+ and Mg2+.
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This question is part of the following fields:
- Cardiovascular
- Pharmacology
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Question 7
Correct
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Question 8
Incorrect
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A 20-year-old male patient lives in a travelling community and has never received any vaccinations. He presents to you with fever.
Which of these statements concerning indications and contraindications for vaccination is FALSE?
Your Answer: 12 weeks should elapse after a dose of human immunoglobulin before a live vaccine is administered
Correct Answer: Premature infants should have the their immunisation schedule adjusted for gestational age
Explanation:All vaccines are contraindicated in individuals with:
A confirmed anaphylactic reaction to a previous dose of the vaccine or a vaccine containing the same antigens.
A confirmed anaphylactic reaction to a component in the vaccine e.g. neomycinLive attenuated vaccines are contraindicated in pregnancy except in cases where risk of infection is more than the risks of vaccination.
During times of acute febrile illness, vaccination should be avoided.
12 weeks should elapse after a dose of human immunoglobulin before a live vaccine is administered.
The normal times recommended for immunization of full-term babies should also be applied to premature infants and correction for gestational age should NOT be implemented.
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This question is part of the following fields:
- Microbiology
- Principles Of Microbiology
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Question 9
Incorrect
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A 60-year-old man diagnosed with chronic kidney disease has an elevated creatinine level and a reduced glomerular filtration rate (GFR).
Which statement concerning glomerular filtration is true?Your Answer: The GFR declines with age after the age of 40 at a rate of approximately 5 ml/min/year
Correct Answer: Creatinine is freely filtered at the glomerulus
Explanation:Glomerular filtration is a passive process. It depends on the net hydrostatic pressure across the glomerular capillaries, the oncotic pressure, and the intrinsic permeability of the glomerulus.
The mean values for glomerular filtration rate (GFR) in young adults are 130 ml/min/1.73m2 in males and 120 ml/min/1.73m2in females.
The GFR declines with age after the age of 40 at a rate of approximately 1 ml/min/year.
The Cockcroft and Gault formula overestimates creatinine in obese patients. This is because their endogenous creatinine production is less than that predicted by overall body weight.
Creatinine is used in the estimation of GFR because it is naturally produced by muscle breakdown, not toxic, not produced by the kidney, freely filtered at the glomerulus, not reabsorbed from the nephron, and does not alter GFR.
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This question is part of the following fields:
- Physiology
- Renal Physiology
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Question 10
Correct
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A patient presents with a rash for dermatological examination. A large area of purplish discolouration of the skin that measures 2 cm in diameter and does not blanch when pressure is applied is seen .
What is the best description of this rash that you have found on examination?
Your Answer: Ecchymoses
Explanation: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.
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.
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This question is part of the following fields:
- General Pathology
- Pathology
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Question 11
Correct
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AÂ patient had a left Colles' fracture, which you were able to repair. It was their second fragility fracture this year, and you'd like to provide them some tips on how to keep their bones healthy.
What percentage of the calcium in the body is kept in the bones? Only ONE response is acceptable.Your Answer: 99%
Explanation:Calcium is stored in bones for nearly all of the body’s calcium, but it is also found in some cells (most notably muscle cells) and the blood. The average adult diet comprises roughly 25 mmol of calcium per day, of which the body absorbs only about 5 mmol.
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This question is part of the following fields:
- Endocrine Physiology
- Physiology
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Question 12
Incorrect
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Which of the following is a well recognised adverse effect of prochlorperazine:
Your Answer: Lactic acidosis
Correct Answer: Acute dystonic reaction
Explanation:Adverse actions include anticholinergic effects such as drowsiness, dry mouth, and blurred vision, extrapyramidal effects, and postural hypotension. Phenothiazines can all induce acute dystonic reactions such as facial and skeletal muscle spasms and oculogyric crises; children (especially girls, young women, and those under 10 kg) are particularly susceptible.
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This question is part of the following fields:
- Central Nervous System
- Pharmacology
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Question 13
Incorrect
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Which of the following clinical features would you NOT expect to see in a tibial nerve palsy:
Your Answer: Weakened inversion of the foot
Correct Answer: Weakened eversion of the foot
Explanation:Damage to the tibial nerve results in loss of plantarflexion of the ankle and weakness of inversion of the foot resulting in a shuffling gait, clawing of the toes and loss of sensation in its cutaneous distribution.
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This question is part of the following fields:
- Anatomy
- Lower Limb
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Question 14
Incorrect
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A patient presents with a history of excessive thirst, urination and high fluid intake. His blood sugar is normal. You estimate his osmolarity as part of his work-up.
Which of these equations can be used to estimate osmolarity?
Your Answer: 2 (Na + ) + K + - (Glucose + Urea)
Correct Answer: 2 (Na + ) + 2 (K + ) + Glucose + Urea
Explanation:Osmolality and osmolarity are measurements of the solute concentration of a solution. Although the two terms are often used interchangeably, there are differences in the definitions, how they are calculated and the units of measurement used.
Osmolarity, expressed as mmol/L, is an estimation of the osmolar concentration of plasma. It is proportional to the number of particles per litre of solution.
Measured Na+, K+, urea and glucose concentrations are used to calculate the value indirectly.
It is unreliable in pseudohyponatremia and hyperproteinaemia.The equations used to calculate osmolarity are:
Osmolarity = 2 (Na+) + 2 (K+) + Glucose + Urea (all in mmol/L)
OR
Osmolarity = 2 (Na+) + Glucose + Urea (all in mmol/L)Doubling of sodium accounts for the negative ions associated with sodium, and the exclusion of potassium approximately allows for the incomplete dissociation of sodium chloride.
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This question is part of the following fields:
- Basic Cellular Physiology
- Physiology
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Question 15
Correct
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Which of the following statements about propofol is TRUE:
Your Answer: Propofol has some antiemetic action.
Explanation:Propofol has some antiemetic properties. It’s for this reason that it’s used to treat postoperative nausea and vomiting. Propofol is mostly processed in the liver, with the kidneys excreting just around 1% of it unaltered. Propofol, unlike thiopental, does not produce tissue necrosis when it is extravasated. Propofol lowers intracranial pressure via lowering brain metabolic rate and cerebral blood flow. Propofol is thought to be safe for people with bronchial asthma and chronic obstructive pulmonary disease.
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This question is part of the following fields:
- Anaesthesia
- Pharmacology
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Question 16
Incorrect
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Which of the following conditions manifests hyperkalaemia as one of its symptoms?
Your Answer: Type 1 renal tubular acidosis
Correct Answer: Congenital adrenal hyperplasia
Explanation:Plasma potassium greater than 5.5 mmol/L is hyperkalaemia or elevated plasma potassium level. Among the causes of hyperkalaemia include congenital adrenal hyperplasia.
Congenital adrenal hyperplasia is a general term referring to autosomal recessive disorders involving a deficiency of an enzyme needed in cortisol and/or aldosterone synthesis. The level of cortisol and/or aldosterone deficiency affects the clinical manifestations of congenital adrenal hyperplasia. When it involves hypoaldosteronism, it can result in hyponatremia and hyperkalaemia. While hypercortisolism can cause hypoglycaemia.
The other causes of hyperkalaemia may include renal failure, excess potassium supplementation, Addison’s disease (adrenal insufficiency), renal tubular acidosis (type 4), rhabdomyolysis, burns, trauma, Tumour lysis syndrome, acidosis, and medications such as ACE inhibitors, angiotensin receptor blockers, NSAIDs, beta-blockers, digoxin, and suxamethonium.
Bartter’s syndrome is characterized by hypokalaemic alkalosis with normal to low blood pressure.
Type 1 and 2 renal tubular acidosis both cause hypokalaemia.
Gitelman’s syndrome is a defect of the distal convoluted tubule of the kidney. It causes metabolic alkalosis with hypokalaemia and hypomagnesemia.
And excessive liquorice ingestion causes hypermineralocorticoidism and hypokalaemia as well. Thus, among the choices, only congenital adrenal hyperplasia can cause hyperkalaemia
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This question is part of the following fields:
- Physiology
- Renal Physiology
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Question 17
Incorrect
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Antidiuretic hormone (ADH) is synthesised by which of the following:
Your Answer: Anterior pituitary
Correct Answer: Hypothalamus
Explanation:Antidiuretic hormone is synthesised in the hypothalamus and transported to the posterior pituitary within nerve fibres where it is stored in secretory granules. ADH binds V2 receptors on renal principal cells in the late distal tubule and collecting ducts, raising cAMP levels and causing intracellular vesicles to fuse with the apical membrane. In their membrane these vesicles have water channels called aquaporins, which increase the water permeability allowing greater water reabsorption and concentration of urine. Excess levels of ADH results in syndrome of inappropriate ADH secretion (SIADH) characterised by hyponatremia with concomitant hypo-osmolality and high urine osmolality.
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This question is part of the following fields:
- Endocrine
- Physiology
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Question 18
Incorrect
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Which of the following clinical features is most suggestive of a lesion of the frontal lobe:
Your Answer: Hemispatial neglect
Correct Answer: Conjugate eye deviation towards the side of the lesion
Explanation:Conjugate eye deviation towards the side of the lesion is seen in damage to the frontal eye field of the frontal lobe. Homonymous hemianopia is typically a result of damage to the occipital lobe (or of the optic radiation passing through the parietal and temporal lobes). Auditory agnosia may been seen in a lesion of the temporal lobe. Hemispatial neglect may be seen in a lesion of the parietal lobe. Receptive dysphasia is seen in damage to Wernicke’s area, in the temporal lobe.
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This question is part of the following fields:
- Anatomy
- Central Nervous System
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Question 19
Correct
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Which of the following nerves provides cutaneous innervation to the posterior surface of the scrotum?
Your Answer: Branch of the perineal nerve
Explanation:The following nerves provide cutaneous innervation to the scrotum, and other anatomic structures:
The perineal nerve supplies the muscles in the urogenital triangle, and the skin on the posterior surface of the scrotum (or labia majora).
The genital branch of the genitofemoral nerve supplies the cremaster muscle, the skin over the anterior surface of the thigh, and the anterolateral surface of the scrotum.
The ilioinguinal nerve supplies the external oblique, internal oblique, transversus abdominis, skin of the upper medial aspect of thigh, the root of the penis and the anterior surface of the scrotum in the male, and the mons pubis and labia majora in the female.
The posterior cutaneous nerve of the thigh, or posterior femoral cutaneous nerve, supplies the skin over the lower medial quadrant of the buttock, the inferior skin of the scrotum or labium majus, and the back of the thigh and the upper part of the leg.
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This question is part of the following fields:
- Abdomen And Pelvis
- Anatomy
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Question 20
Correct
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Regarding aciclovir, which of the following statements is INCORRECT:
Your Answer: Aciclovir eradicates herpes simplex virus from the body.
Explanation:Aciclovir is active against herpesviruses but does not eradicate latent virus.
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This question is part of the following fields:
- Infections
- Pharmacology
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Question 21
Correct
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A 16-year-old male with a known case of Haemophilia A is referred to your orthopaedic clinic for evaluation and aspiration of a hemarthrosis of the left knee joint.
Out of the modes of inheritance listed below, which one is present in this disease?Your Answer: X-linked recessive
Explanation:All the Haemophilia’s have an X-linked recessive inheritance pattern, so they only manifest in male patients. Diseases with a mitochondrial inheritance pattern include MELAS syndrome, Leigh syndrome, LHON and MERRF syndrome. Autosomal dominant disorders include Huntingdon disease and Marfan syndrome. X-linked dominant diseases include Fragile X syndrome. Autosomal recessive diseases include cystic fibrosis and sickle cell disease.
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This question is part of the following fields:
- Haematology
- Pathology
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Question 22
Incorrect
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While studying fluid homeostasis in the body, you encounter the term exudate. Exudate is a fluid that leaks out of the intravascular space due to changes in the permeability of the microcirculation secondary to inflammation.
Which ONE of the following conditions would not be listed among the causes of an exudate?Your Answer: Rheumatoid arthritis
Correct Answer: Myxoedema
Explanation:An exudate is an inflammatory fluid that leaks out of the intravascular space due to increased vascular permeability and intravascular pressure. It is mostly caused by local processes and can occur in the following conditions:
1) Infection (e.g. pneumonia)
2) Malignancy
3) Pericarditis
4) Collagen vascular diseases, e.g., Rheumatoid ArthritisMyxoedema is a state of severe hypothyroidism in which deposition of mucopolysaccharides occurs in the dermis. This causes a transudative effusion, typically in the pretibial region.
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This question is part of the following fields:
- General Pathology
- Pathology
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Question 23
Incorrect
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You've been summoned to the resuscitation area to assist a patient who is having a seizure. As part of the treatment protocol, a benzodiazepine dose is given.
Which of the following statements about the use of benzodiazepines in seizures is correct?Your Answer: Benzodiazepines have low lipid solubility
Correct Answer: Lorazepam can be given by the rectal route
Explanation:A single dose of IV benzodiazepine will terminate the seizure in 60 to 80 percent of patients who present with seizures.
Because benzodiazepines are lipid-soluble, they cross the blood-brain barrier quickly. This explains their quick onset of action.
As a first-line treatment, IV lorazepam should be given. If IV lorazepam is not available, IV diazepam can be used instead, and buccal midazolam can be used if intravenous access cannot be established quickly. Lorazepam can be administered via the rectal route, but it is less reliable and has a lower absorption rate and bioavailability.
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This question is part of the following fields:
- CNS Pharmacology
- Pharmacology
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Question 24
Incorrect
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Anatomical barriers to infection include all of the following EXCEPT:
Your Answer: Flushing action of tears
Correct Answer: Mucociliary escalator in the gastrointestinal tract
Explanation:Anatomical barriers to infection include:tight junctions between cells of the skin and mucosal membranesthe flushing action of tears, saliva and urinethe mucociliary escalator in the respiratory tract (together with the actions of coughing and sneezing)the acidic pH of gastric and vaginal secretionsthe acidic pH of the skin (maintained by lactic acid and fatty acids in sebum)enzymes such as lysozyme found in saliva, sweat and tearspepsin present in the stomachbiological commensal flora formed on the skin and the respiratory, gastrointestinal and genitourinary tracts which protect the host by competing with pathogenic bacteria for nutrients and attachment sites and by producing antibacterial substances
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This question is part of the following fields:
- Microbiology
- Principles
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Question 25
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 26
Incorrect
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During quiet respiration, position of the right oblique fissure can be marked by a line drawn on the thoracic wall that:
Your Answer: Begins at the spinous process of T6, crosses the fifth intercostal space laterally and follows the contour of rib 7 anteriorly.
Correct Answer: Begins at the spinous process of T4, crosses the fifth intercostal space laterally and follows the contour of rib 6 anteriorly.
Explanation:During quiet respiration, the approximate position of the right oblique fissure can be marked by a line on the thoracic wall that begins at the spinous process of vertebra T4, crosses the fifth intercostal space laterally and then follows the contour of rib 6 anteriorly.
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This question is part of the following fields:
- Anatomy
- Thorax
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Question 27
Correct
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Which of the following is a clinical effect of hyperkalaemia:
Your Answer: Muscle weakness
Explanation:Clinical features of hyperkalaemia may include:
paraesthesia, muscle weakness or paralysis, cardiac conduction abnormalities and dysrhythmias.Clinical features of hypokalaemia may include:
muscle weakness, muscle cramps, rhabdomyolysis and myoglobinuria, ascending paralysis resulting in respiratory failure, constipation, gut ileus with distension, anorexia, nausea and vomiting, impaired ADH action with polyuria and polydipsia, ECG changes and cardiac arrhythmias. -
This question is part of the following fields:
- Physiology
- Renal
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Question 28
Correct
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Which of the following is an ECG change typically associated with hyperkalaemia:
Your Answer: Wide QRS complex
Explanation:Hyperkalaemia causes a rapid reduction in resting membrane potential leading to increased cardiac depolarisation and muscle excitability. This in turn results in ECG changes which can rapidly progress to ventricular fibrillation or asystole. Very distinctive ECG changes that progressively change as the K+level increases:
K+>5.5 mmol/l – peaked T waves (usually earliest sign of hyperkalaemia), repolarisation abnormalities
K+>6.5 mmol/l – P waves widen and flatten, PR segment lengthens, P waves eventually disappear
K+>7.0 mmol/l – Prolonged QRS interval and bizarre QRS morphology, conduction blocks (bundle branch blocks, fascicular blocks), sinus bradycardia or slow AF, development of a sine wave appearance (a pre-terminal rhythm)
K+>9.0 mmol/l – Cardiac arrest due to asystole, VF or PEA with a bizarre, wide complex rhythm. -
This question is part of the following fields:
- Physiology
- Renal
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Question 29
Incorrect
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Damage to this nerve affects the flexor digitorum longus.
Your Answer: Sciatic nerve
Correct Answer: Tibial nerve
Explanation:Like all muscles in the deep posterior compartment of the leg, flexor digitorum longus muscle is innervated by branches of the tibial nerve (root value L5, S1 and S2) which is a branch of sciatic nerve.
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This question is part of the following fields:
- Anatomy
- Lower Limb
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Question 30
Correct
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A 37-year-old man presents with breathlessness on exertion and dry cough, fever for the past 2 days and bilateral pleuritic chest pain.
He had been diagnosed with HIV and commenced on HAART but due to side effects, his compliance has been poor over the last few months.
On examination you note scattered crackles and wheeze bilaterally, cervical and inguinal lymphadenopathy, and oral thrush. At rest his oxygen saturation is 97% but this drops to 87% on walking. There is perihilar fluffy shadowing seen on his chest X-ray.
Which of these organisms is the most likely causative organism?
Your Answer: Pneumocystis jirovecii
Explanation:All of the organisms listed above can cause pneumonia in immunocompromised individuals but the most likely cause in this patient is Pneumocystis jirovecii.
It is a leading AIDS-defining infection in HIV-infected individuals and causes opportunistic infection in immunocompromised individuals. HIV patients with a CD4 count less than 200 cells/mm3 are more prone.
The clinical features of pneumonia caused by Pneumocystis jirovecii are:
Fever, chest pain, cough (usually non-productive), exertional dyspnoea, tachypnoea, crackles and wheeze.
Desaturation on exertion is a very sensitive sign of Pneumocystis jirovecii pneumonia.Chest X-ray can show perihilar fluffy shadowing (as is seen in this case) but can also be normal.
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This question is part of the following fields:
- Microbiology
- Specific Pathogen Groups
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SESSION STATS - PERFORMANCE PER SPECIALTY
