A 3-year-old female child with repeated admissions as bleeding tendency in a form of spontaneous ecchymosis and bleeding through the nose and urine. She had another daughter who died because of similar undiagnosed illness. The mother is a staff nurse and she is highly concerned about her child illness. Lab investigations usually show either PT and/or PTT prolongation with normal platelets, which usually normalized after empiric vitamin K administration. The father is a petrol engineer and never seen accompanying the family. Of the following, the MOST helpful investigation is

Correct Answer: A

Rationale: Factor VII deficiency is consistent with the described coagulation profile (PT prolongation, normal platelets, improvement with vitamin K). Factor II assay and von Willebrand factor assay are less relevant here.

Correct Answer: A

Rationale: The 'triangular cord' sign, a fibrotic remnant of bile ducts, is a characteristic ultrasound finding in biliary atresia.

Correct Answer: C

Rationale: Cyproheptadine, an antihistamine with serotonin-blocking properties, is effective in treating cold-induced urticaria.

Correct Answer: C

Rationale: An Ambu bag provides manual positive pressure ventilation, making it the preferred method for oxygen delivery in a child with respiratory arrest.

Correct Answer: D

Rationale: Calcium gluconate stabilizes cardiac membranes, preventing life-threatening arrhythmias without affecting serum potassium levels.

Correct Answer: B

Rationale: Coarctation of the aorta typically causes weak femoral pulses but does not affect the right brachial pulse significantly, as the narrowing is usually distal to the right subclavian artery.

Correct Answer: B

Rationale: Three or more wheezing episodes lasting over one day in a year indicate persistent asthma, warranting long-term control therapy.

Correct Answer: B

Rationale: Patients should be monitored for at least 4 hours due to the risk of biphasic anaphylaxis, which can recur after initial resolution.

Correct Answer: C

Rationale: Climate change poses a major threat to food security by affecting crop yields and causing extreme weather events that disrupt agriculture.