Correct Answer: A

Rationale: Acute rheumatic fever (ARF) is a complication of group A Streptococcus infection, diagnosed by the Jones criteria. Arthritis (
Choice
A) is the most common presenting feature, occurring in 60-75% of cases, typically as migratory polyarthritis affecting large joints. Carditis (
Choice
B) occurs in 50-60% of cases and is a major criterion, but it’s less frequent at initial presentation than arthritis. Erythema marginatum (
Choice
C) and subcutaneous nodules (
Choice
D) are rare, occurring in <5% and <1% of cases, respectively, and are not the most common presenting features. Arthritis’s high prevalence and early onset make it the correct answer.

Correct Answer: C

Rationale: Lissencephaly, a smooth brain appearance, results from defective neuronal migration (
Choice
C) during weeks 8-14 of gestation, impairing cortical layer formation. Myelination (
Choice
A) occurs later. Neuronal and glial proliferation (
Choice
B) precedes migration. Neuronal organisation (
Choice
D) follows migration. Migration defects cause lissencephaly’s hallmark.

Correct Answer: C

Rationale:
Choice C is false; an emergency court order is indicated if parents refuse hospitalization in suspected abuse with safety risks (AAP). All other statements (A, B, D, E) are true per abuse protocols.

Correct Answer: C

Rationale: Length may stay normal in chronic malnutrition as stunting lags, unlike weight-for-height or weight , which drop acutely (WHO). D, E decline later.

Correct Answer: D

Rationale: Gastroenteritis causes hypovolemic hyponatremia via fluid loss and hypotonic replacement, per clinical data (AAP). A-C, E are less common.