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Question 1
Correct
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Approximately how long is the duration of a lidocaine block (when given with adrenaline):
Your Answer: 90 minutes
Explanation:Lidocaine is a tertiary amine that is primarily used as a local anaesthetic but can also be used intravenously in the treatment of ventricular dysrhythmias.
Lidocaine works as a local anaesthetic by diffusing in its uncharged base form through neural sheaths and the axonal membrane to the internal surface of the cell membrane sodium channels. Here it alters signal conduction by blocking the fast voltage-gated sodium channels. With sufficient blockage, the membrane of the postsynaptic neuron will not depolarise and will be unable to transmit an action potential, thereby preventing the transmission of pain signals.
Each 1 ml of plain 1% lidocaine solution contains 10 mg of lidocaine hydrochloride. The maximum safe dose of plain lidocaine is 3 mg/kg. When administered with adrenaline 1:200,000, the maximum safe dose is 7 mg/kg. Because of the risk of vasoconstriction and tissue necrosis, lidocaine should not be used in combination with adrenaline in extremities such as fingers, toes, and the nose.
The half-life of lidocaine is 1.5-2 hours. Its onset of action is rapid within a few minutes, and it has a duration of action of 30-60 minutes when used alone. Its duration of action is prolonged by co-administration with adrenaline (about 90 minutes).
Lidocaine tends to cause vasodilatation when used locally. This is believed to be due mainly to the inhibition of action potentials via sodium channel blocking in vasoconstrictor sympathetic nerves. -
This question is part of the following fields:
- Anaesthesia
- Pharmacology
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Question 2
Incorrect
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Which of the following is NOT a heritable risk factor for venous thrombosis:
Your Answer: Antithrombin Deficiency
Correct Answer: Von Willebrand disease
Explanation:Approximately one-third of patients who suffer DVT or PE have an identifiable heritable risk factor, although additional risk factors are usually present when they develop the thrombosis. The history of a spontaneous DVT in a close relative increases an individual’s risk of DVT even if no known genetic predisposition can be identified.
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This question is part of the following fields:
- Haematology
- Pathology
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Question 3
Correct
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Which of the following hormones regulates Na+reabsorption in the proximal tubule:
Your Answer: Angiotensin II
Explanation:Angiotensin II increases Na+reabsorption from the proximal tubule (by activating Na+/H+antiporters).
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This question is part of the following fields:
- Physiology
- Renal
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Question 4
Correct
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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 5
Incorrect
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Where in the nephron is most K+reabsorbed:
Your Answer: Distal convoluted tubule
Correct Answer: Proximal tubule
Explanation:Approximately 65 – 70% of filtered K+is reabsorbed in the proximal tubule. Potassium reabsorption is tightly linked to that of sodium and water. The reabsorption of sodium drives that of water, which may carry some potassium with it. The potassium gradient resulting from the reabsorption of water from the tubular lumen drives the paracellular reabsorption of potassium and may be enhanced by the removal of potassium from the paracellular space via the Na+/K+ATPase pump. In the later proximal tubule, the positive potential in the lumen also drives the potassium reabsorption through the paracellular route.
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This question is part of the following fields:
- Physiology
- Renal
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Question 6
Correct
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A 20-year-old male receives a small cut over his hand while climbing a fence causing it to bleed. Upon applying pressure for a few minutes, the bleeding stops. Which one of the following physiological components of the blood is responsible for the primary haemostasis reaction, such as in this case?
Your Answer: Platelet plug formation
Explanation:Haemostasis is your body’s defence against an injury that causes bleeding. It stops bleeding in three main steps:
1) Primary haemostasis – formation of a weak platelet plug
– The primary reaction of the body is to cause local vasoconstriction at the site of injury and decrease blood flow to the affected area
– the release of cytokines and inflammatory markers lead to adhesion of platelets and aggregation at the site of injury forming a platelet plug
– the injured vessel wall has exposed subendothelial collagen that releases von Willebrand factorAny damage to the vessel wall causes the release of the Von Willebrand factor, which is necessary for platelet adhesion. Tissue Thromboplastin is also released, which activates the coagulation pathway, a component of secondary haemostasis. The coagulation cascade ultimately results in the conversion of fibrinogen to fibrin.
2) Secondary haemostasis
3) FibrinolysisFibrin (factor Ia) is a long, thin protein with branches produced at the end of the coagulation cascade when fibrinogen (factor I) is converted to fibrin, which stabilizes the blood clot.
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This question is part of the following fields:
- General Pathology
- Pathology
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Question 7
Incorrect
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Metabolic hyperaemia harmonizes local blood flow with local O2 demand. If there is an increase in metabolic rate, the production of vasoactive metabolites increases. These metabolites act locally on the surrounding arterioles, causes vasodilation and an increase blood supply.
Which of these metabolites is the most potent vasodilator in skeletal muscle?Your Answer: H +
Correct Answer: K +
Explanation:Hyperaemia is the process where the body adjusts blood flow to meet the metabolic needs of different tissues in health and disease. Vasoactive mediators that take part in this process include K+, adenosine, CO2, H+, phosphates and H2O2. Although the mechanism is not clear, all these mediators likely contribute to some extent at different points.
Specific organs are more sensitive to specific metabolites:
K+ and adenosine are the most potent vasodilators in skeletal musclesCO2 and K+ are the most potent vasodilators in cerebral circulation.
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This question is part of the following fields:
- Cardiovascular Physiology
- Physiology
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Question 8
Correct
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A 64-year-old woman had a humerus midshaft fracture due to tripping on a curb and falling on her left arm. She might also have damaged which of the following structures?
Your Answer: Radial nerve and deep brachial artery
Explanation:The radial nerve and brachial artery are most likely to be damaged in humerus fractures. They are tethered together to the bone and cannot withstand the forces applied to it as a result of the displacement.
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This question is part of the following fields:
- Anatomy
- Upper Limb
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Question 9
Correct
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An X-ray of a 24-year-old female hockey player who arrives at the hospital with a left foot injury reveals an avulsion fracture of the fifth metatarsal tuberosity. Which of the following muscles is most likely responsible for the movement of the fractured fragment?
Your Answer: Fibularis brevis
Explanation:An avulsion fracture of the base of the fifth metatarsal happens when the ankle is twisted inwards.
When the ankle is twisted inwards a muscle called the fibularis brevis contracts to stop the movement and protect the ligaments of the ankle.
The base of the fifth metatarsal is where this muscle is attached. The group of lateral leg muscles that function to plantarflex the foot includes the fibularis brevis and the fibularis longus.
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This question is part of the following fields:
- Anatomy
- Lower Limb
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Question 10
Correct
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Where:
Capillary hydrostatic pressure is (P c)Hydrostatic pressure in the interstices is (P I )
Plasma oncotic pressure is (Ï€ p)Interstitial oncotic pressure is (Ï€ i)
Which of the following formulas best represents fluid flow at the capillary bed?
Your 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(Ï€p– Ï€i)]
Volume /min = (Pc-Pi) – (Ï€p–πi) describes the fluid circulation at the capillaries.
Where:
Pc= capillary hydrostatic pressure
Pi= interstitial hydrostatic pressure
Ï€p= plasma oncotic pressure
Ï€i= interstitial oncotic pressure -
This question is part of the following fields:
- Cardiovascular Physiology
- Physiology
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Question 11
Correct
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An very unwell patient is receiving treatment in your hospital's HDU and is found to have an Escherichia coli O157 infection.
Which one of these statements about Escherichia coli O157 is true?Your Answer: Haemolytic uraemic syndrome develops in approximately 6% of patients
Explanation:Escherichia coli O157 is a serotype of Escherichia coli.
The Escherichia coliO157 strain is ‘enterohaemorrhagic’ and causes severe forms of acute haemorrhagic diarrhoea. It can also cause non-haemorrhagic diarrhoea.Incubation period of Escherichia coli O157 is usually 3-4 days and bloody diarrhoea usually begins on the 3rd or 4th day of the infection.
Infections with Escherichia coliO157 are more common during the warmer months than in winter.
Haemolytic uraemic syndrome develops in approximately 6% of patients. It is commonly seen in children and in the elderly.
Escherichia coli O157 can also cause:
Haemorrhagic colitis
Haemolytic uraemic syndrome
Thrombotic thrombocytopenic purpura but not immune thrombocytopenic purpura. -
This question is part of the following fields:
- Microbiology
- Specific Pathogen Groups
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Question 12
Incorrect
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A 7-days-old neonate is taken to the emergency department. She's pyretic, lethargic, and unresponsive, and her fontanelle has bulged. Antibiotics are started, and a lumbar puncture reveals Gram-negative rods. Which pathogen is most likely to be the cause:
Your Answer: Group B streptococcus (GBS)
Correct Answer: Escherichia coli
Explanation:Among neonates, group B streptococci (GBS) are the most commonly identified causes of bacterial meningitis, implicated in roughly 50% of all cases. Escherichia coli(Gram-negative rods) accounts for another 20%. Thus, the identification and treatment of maternal genitourinary infections is an important prevention strategy.
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This question is part of the following fields:
- Infections
- Microbiology
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Question 13
Correct
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Regarding acute lymphoblastic leukaemia (ALL), which of the following statements is CORRECT:
Your Answer: 75% of cases occur before the age of 6 years.
Explanation:Acute lymphoblastic leukaemia (ALL) is caused by an accumulation of lymphoblasts in the bone marrow and is the most common malignancy of childhood. The incidence of ALL is highest at 3 – 7 years, with 75% of cases occurring before the age of 6. 85% of cases are of B-cell lineage. Haematological investigations reveal a normochromic normocytic anaemia with thrombocytopenia in most cases. There is great variation in the chance of individual patients achieving a long-term cure based on a number of biological variables. Approximately 25% of children relapse after first-line therapy and need further treatment but overall 90% of children can expect to be cured. The cure rate in adults drops significantly to less than 5% over the age of 70 years.
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This question is part of the following fields:
- Haematology
- Pathology
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Question 14
Incorrect
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Which of the following neurotransmitter and receptor combinations is present at the neuromuscular junction:
Your Answer: Acetylcholine acting at muscarinic receptors
Correct Answer: Acetylcholine acting at nicotinic receptors
Explanation:At the neuromuscular junction, acetylcholine is released from the prejunctional membrane which acts on cholinergic nicotinic receptors on the postjunctional membrane.
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This question is part of the following fields:
- Basic Cellular
- Physiology
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Question 15
Correct
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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 16
Correct
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A 45-year-old woman presents with persistent palpitations for the past two days. She has a good haemodynamic balance. An ECG is performed, which reveals that she has atrial flutter. The patient is examined by a cardiology registrar, who recommends using a 'rate control' strategy while she waits for cardioversion.
Which of the drugs listed below is the best fit for this strategy?Your Answer: Bisoprolol
Explanation:In atrial flutter, ventricular rate control is usually used as a stopgap measure until sinus rhythm can be restored. A beta-blocker (such as bisoprolol), diltiazem, or verapamil can be used to lower the heart rate.
Electrical cardioversion, pharmacological cardioversion, or catheter ablation can all be used to restore sinus rhythm. Cardioversion should not be attempted until the patient has been fully anticoagulated for at least three weeks if the duration of atrial flutter is unknown or has lasted for more than 48 hours. Emergency electrical cardioversion is the treatment of choice when there is an acute presentation with haemodynamic compromise. For the treatment of recurrent atrial flutter, catheter ablation is preferred.
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This question is part of the following fields:
- Cardiovascular Pharmacology
- Pharmacology
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Question 17
Incorrect
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Regarding Clostridium species, which of the following statements is INCORRECT:
Your Answer: They are rod-shaped.
Correct Answer: They are facultative anaerobes.
Explanation:Clostridium spp. are obligatory anaerobic spore-forming Gram-positive bacilli. Toxin production is the main pathogenicity mechanism.
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This question is part of the following fields:
- Microbiology
- Pathogens
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Question 18
Correct
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What does the correlation coefficient r = 0 indicate with regards to linear relationships between two variables?
Your Answer: There is no correlation between two variables
Explanation:r = 0 if there is no correlation between two variables.
The closer that r is to 0, the weaker the correlation. -
This question is part of the following fields:
- Evidence Based Medicine
- Statistics
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Question 19
Correct
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Which of the following pathogens causes tetanus:
Your Answer: Clostridium tetani
Explanation:Tetanus is caused by Clostridium tetani, a bacterium. Tetanus can cause mild spasms to severe whole-body contractions, suffocation, and heart attack.
Gas gangrene and food poisoning are both caused by Clostridium perfringens.
Pseudomembranous colitis is caused by Clostridium difficile.
Urinary tract infections, respiratory infections, dermatitis, soft tissue infections, bacteraemia, bone and joint infections, gastrointestinal infections, and a variety of systemic infections are all caused by Pseudomonas aeruginosa.
Pharyngitis, skin infections, acute rheumatic fever, scarlet fever, poststreptococcal glomerulonephritis, toxic shock–like syndrome, and necrotizing fasciitis can all be caused by Streptococcus pyogenes infection.
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This question is part of the following fields:
- Microbiology
- Pathogens
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Question 20
Incorrect
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Regarding ampicillin, which of the following statements is CORRECT:
Your Answer: Ampicillin is first line treatment for acute sore throat.
Correct Answer: Ampicillin may cause a widespread maculopapular rash in a patient with glandular fever.
Explanation:Ampicillin is a broad-spectrum antibiotic, active against certain Gram-positive and Gram-negative organisms but is inactivated by penicillinases (similar to amoxicillin in spectrum). Ampicillin is associated with high levels of resistance, therefore it is often not appropriate for blind treatment of infection. It is principally indicated for the treatment of exacerbations of chronic bronchitis and middle ear infections, both of which may be due to Streptococcus pneumoniae and H. influenzae, and for urinary tract infections.
Maculopapular rashes commonly occur with ampicillin (and amoxicillin) but are not usually related to true penicillin allergy. They almost always occur in patients with glandular fever; thus broad-spectrum penicillins should not be used for blind treatment of a sore throat. The risk of rash is also increased in patients with acute or chronic lymphocytic leukaemia or in cytomegalovirus infection.
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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 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 22
Correct
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In the emergency department, a 50-year-old female appears with a lack of sensation over the front two-thirds of her tongue. Taste and salivation are both present. The patient might have damage which of her nerves?
Your Answer: Lingual nerve
Explanation:The lingual nerve, a branch of the mandibular nerve, transmits sensation to the anterior two-thirds of the tongue.
The chorda tympani, a branch of the facial nerve, transmits taste to the front two-thirds of the tongue as well as secretomotor innervation to the submandibular and sublingual glands.
As a result, any damage to the lingual nerve can cause changes in salivary secretion on the affected side, as well as a loss of taste in the anterior two-thirds of the tongue and temporary or permanent sensory changes in the anterior two-thirds of the tongue and the floor of the mouth.
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This question is part of the following fields:
- Anatomy
- Cranial Nerve Lesions
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Question 23
Incorrect
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A 23-year-old male presents to his family physician with the complaint of repeated episodes of abdominal pain and the passage of dark coloured urine every morning. He also reports increasing fatigue over the past several months. On examination, there are raised, painful red nodules over the skin of the back. Laboratory workup shows haemolytic anaemia, leukopenia and thrombocytopenia.
Which one of the following disorders is this patient most likely to have?Your Answer: Paroxysmal cold haemoglobinuria
Correct Answer: Paroxysmal nocturnal haemoglobinuria
Explanation:Paroxysmal nocturnal haemoglobinuria is an acquired genetic disorder that causes a decrease in red blood cells due to a membrane defect that allows increased complement binding to RBCs, causing haemolysis. Patients complain of dark-coloured urine first in the morning due to haemoglobinuria secondary to lysis of red blood cells overnight.
Thrombosis occurs, which affects hepatic, abdominal, cerebral and subdermal veins. Thrombosis of hepatic veins can lead to Budd-Chiari syndrome, thrombosis of subdermal veins can lead to painful nodules on the skin, and thrombosis of cerebral vessels can lead to stroke. The presence of dark urine in the morning only and at no other time differentiates this condition from other conditions.
Multiple myeloma would present with bone pain, signs of radiculopathy if there were nerve root compression and a history of repeated infections.
Patients with Non-Hodgkin Lymphoma would complain of enlarged lymph nodes, fatigue, fever, weight loss and a history of repeated infections.
Acute lymphoblastic leukaemia presents more commonly in children than in adults. The patient would complain of bone pain, and on examination, there would be hepatosplenomegaly.
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This question is part of the following fields:
- Haematology
- Pathology
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Question 24
Incorrect
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Atrial natriuretic peptide (ANP) acts to cause all of the following effects EXCEPT for:
Your Answer: Inhibits renin release
Correct Answer: Vasoconstricts the afferent arteriole
Explanation:ANP acts to:
Inhibit Na+ reabsorption in the distal nephron (through inhibition of ENaC in principal cells)
Suppress the production of renin
Suppress the production of aldosterone
Suppress the production of ADH
Cause renal vasodilation, increasing the glomerular filtration rate -
This question is part of the following fields:
- Physiology
- Renal
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Question 25
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 26
Correct
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A 58-year-old man showing symptoms of increase in weight, proximal muscular weakening and withering, easy bruising, and acne. You notice that he has a full, plethoric aspect to his face, as well as significant supraclavicular fat pads, when you examine him. His blood pressure is 158/942Â mmHg, and his glucose tolerance has lately been impaired. His potassium level is 3.2Â mmol/L.
What is the MOST LIKELY diagnosis?Your Answer: Cushing’s syndrome
Explanation:Cushing’s syndrome is a group of symptoms and signs brought on by long-term exposure to high amounts of endogenous or exogenous glucocorticoids. Cushing’s syndrome affects about 10-15 persons per million, and it is more common in those who have had a history of obesity, hypertension, or diabetes.
Cushing’s syndrome has a wide range of clinical manifestations that are dependent on the degree of cortisol overproduction. The appearance might be vague and the diagnosis difficult to detect when cortisol levels are just somewhat elevated. On the other hand, in long-term cases of severely increased cortisol levels, the presentation might be colourful and the diagnosis simple.
Cushing’s syndrome has the following clinical features:
Obesity and weight growth in the true sense
Supraclavicular fat pads are fat pads that are located above the clavicle.
Buffalo hump
Fullness and plethora of the face (‘moon facies’)
Muscle atrophy and weakening at the proximal level
Diabetes mellitus, also known as impaired glucose tolerance
Hypertension
Skin thinning and bruising
Depression
Hirsutism
Acne
Osteoporosis
Amenorrhoea or oligomenorrhoeaCortisol levels fluctuate throughout the day, with the greatest levels occurring around 0900 hours and the lowest occurring at 2400 hrs during sleep. The diurnal swing of cortisol levels is lost in Cushing’s syndrome, and levels are greater during the whole 24-hour period. In the morning, levels may be normal, but they may be high at night-time, when they are generally repressed. As a result, random cortisol testing is not an effective screening technique and is not advised.
The following are the two most common first-line screening tests:
Cortisol levels in the urine are measured every 24 hours.
A diagnosis of Cushing’s syndrome can be made if more than two collections measure cortisol excretion more than three times the upper limit of normal.
Physical stress (e.g., excessive exercise, trauma), mental stress (e.g., sadness), alcohol or drug misuse, complex diabetes, and pregnancy can all cause false positives.
Renal dysfunction, inadequate collection, and cyclical Cushing’s disease can all cause false negatives.
The overnight low-dose dexamethasone suppression test (LDDST) involves giving 1 mg of dexamethasone at 11 p.m. and measuring blood cortisol levels at 8 a.m. the next day.
Cushing’s syndrome is diagnosed when cortisol is not suppressed to less than 50 nmol/L.
It might be difficult to tell the difference between mild Cushing’s disease and normal cortisol production.
False positives can occur as a result of depression, severe systemic sickness, renal failure, prolonged alcohol misuse, old age, and the use of hepatic enzyme-inducing medicines, among other things.
False negatives are extremely uncommon in Cushing’s disease patients.A characteristic biochemical picture might also be helpful in confirming the diagnosis of Cushing’s syndrome. The following are the primary characteristics:
Hypokalaemia
Alkalosis metabolique -
This question is part of the following fields:
- Endocrine Physiology
- Physiology
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Question 27
Correct
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A patient has an elevated potassium level of 6.7 mmol/L. All of the following conditions may cause elevated potassium levels, except for which one?
Your Answer: Bartter’s syndrome
Explanation:Bartter’s syndrome is an autosomal recessive renal tubular disorder characterized by hypokalaemia, hypochloraemia, metabolic alkalosis, and hyperreninemia with normal blood pressure. The underlying kidney abnormality results in excessive urinary losses of sodium, chloride, and potassium.
Bartter’s syndrome does not cause an elevated potassium level, but instead causes a decrease in its concentration (hypokalaemia). The other choices are causes of hyperkalaemia or elevated potassium levels.
Renal failure, Addison’s disease (adrenal insufficiency), congenital adrenal hyperplasia, renal tubular acidosis (type 4), rhabdomyolysis, burns and trauma, tumour syndrome, and acidosis are non-drug causes of hyperkalaemia. On the other hand, drugs that can cause hyperkalaemia include ACE inhibitors, angiotensin receptor blockers, NSAIDs, beta-blockers, digoxin, and suxamethonium.
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This question is part of the following fields:
- Physiology
- Renal Physiology
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Question 28
Correct
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A 67-year-old woman complains of general malaise, nausea, and vomiting. She is perplexed and declares that everything 'looks yellow.' Her potassium level is 6.8 mmol/l, according to a blood test.
Which of the drugs listed below is most likely to be the cause of her symptoms?Your Answer: Digoxin
Explanation:Because digoxin has a narrow therapeutic index, it can cause toxicity both during long-term therapy and after an overdose. Even when the serum digoxin concentration is within the therapeutic range, it can happen.
Acute digoxin toxicity usually manifests itself within 2-4 hours of an overdose, with serum levels peaking around 6 hours after ingestion and life-threatening cardiovascular complications following 8-12 hours.
Chronic digoxin toxicity is most common in the elderly or those with impaired renal function, and it is often caused by a coexisting illness. The clinical signs and symptoms usually appear gradually over days to weeks.
The following are characteristics of digoxin toxicity:
Nausea and vomiting
Diarrhoea
Abdominal pain
Confusion
Tachyarrhythmias or bradyarrhythmias
Xanthopsia (yellow-green vision)
Hyperkalaemia (early sign of significant toxicity)Some precipitating factors are as follows:
Elderly patients
Renal failure
Myocardial ischaemia
Hypokalaemia
Hypomagnesaemia
Hypercalcaemia
Hypernatraemia
Acidosis
Hypothyroidism
Spironolactone
Amiodarone
Quinidine
Verapamil
Diltiazem -
This question is part of the following fields:
- Cardiovascular Pharmacology
- Pharmacology
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Question 29
Correct
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Which ONE statement about homeostasis is true?
Your Answer: Negative feedback occurs via receptors, comparators and effectors
Explanation:Homeostasis is the property of a system in which variables are regulated so that internal conditions remain relatively constant and stable. Homeostasis is achieved by a negative feedback mechanism.
Negative feedback occurs based upon a set point through receptors, comparators and effectors.
The ‘set point’ is a NARROW range of values within which normal function occurs.
The two body systems that regulate homeostasis are the Nervous system and the Endocrine system.
The smooth muscle of the uterus becomes more active towards the end of pregnancy. This is a POSITIVE feedback.
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This question is part of the following fields:
- Basic Cellular Physiology
- Physiology
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Question 30
Correct
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Campylobacter jejuni is primarily spread via which of the following routes:
Your Answer: Faecal-oral route
Explanation:Campylobacter spp. are a common cause of acute infective gastroenteritis, particularly in children, with Campylobacter jejuni responsible for 90% of Campylobacter gastroenteritis. Infection typically follows ingestion of contaminated meat (most frequently undercooked poultry), unpasteurised milk or contaminated water, following which the microorganism invades and colonises the mucosa of the small intestine.
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This question is part of the following fields:
- Microbiology
- Pathogens
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SESSION STATS - PERFORMANCE PER SPECIALTY
