RACP-physiology

Question 1

A patient presents with acute dyspnoea. Which of the following is associated with a paradoxical arterial pulse > 10 mm Hg?
a) Congestive Cardiac Failure
b) Pulmonary Hypertension
c) Severe Asthma
d) Atrial Fibrillation
e) Pneumonia

Answer 1

C) severe asthma

Question 2

25 Male with pneumonia, treated with IV benzylpenicillin and PO azithromycin. His pneumonia improves but becomes very confused, with oedema on his CT brain

You suspected a defect with the urea cycle. If the diagnosis is correct which test is most likely to be abnormal?

A. Ammonia
B. Homocysteine
C. Lactate
D. Calcium
E. Very long chain lipids

Answer 2

A. Ammonia

Question 3

71. In the treatment of hyperkalaemia the mechanism of action of Calcium chloride is

A) Membrane antagonism
B) Increase urinary excretion of potassium
C) Increased intracellular shift of potassium
D) Reduced potassium absorption

Answer 3

A) Membrane antagonism

Question 4

Describe Paracetamol kinetics

Answer 4

• Paracetamol is rapidly absorbed from the small intestine
• Peak concentration is within 2 hours for standard tablet, or 30 min for liquid
• 20% of ingested dose undergoes first-pass metabolism in the gut wall (sulphation)
• Further elimination occurs by hepatic biotransformation
• About 90% is metabolized to inactive sulphate and glucuronide conjugates that are excreted in the urine
• Metabolism of the remainder is via cytochrome P450 and results in the highly reactive intermediary compound NAPQI
• In therapeutic doses, NAPQI is bound to intracellular glutathione and eliminated in the urine as mercapturic adducts
• With increased paracetamol doses, the increased NAPQI depletes glutathione stores and binds to other proteins, causing damage to the hepatocyte

Question 5

What is vitamin B6?

Answer 5

pyridoxine