A 4-year-old boy presents with abdominal pain and currant jelly stools. Ultrasound confirms intussusception. The next step is:

Correct Answer: C

Rationale: Air enema reduces intussusception, per AAP. A, B, D, E are secondary.

Correct Answer: B

Rationale: Intussusception shows a target sign, per AAP. A, C-E differ.

Correct Answer: B

Rationale: A 12-year-old with a small ventricular septal defect (VSD) presents with heart failure, a pansystolic murmur, and an early diastolic murmur, suggesting aortic valve regurgitation (Choice B). Over time, a VSD can distort the aortic root, leading to aortic regurgitation, increased left ventricular volume, and heart failure. Acute rheumatic fever (Choice A) requires fever and inflammation, absent here. Eisenmenger syndrome (Choice C) involves cyanosis from shunt reversal, not present. An increasing left-to-right shunt (Choice D) wouldn’t cause a diastolic murmur. Aortic regurgitation fits the clinical findings.

Correct Answer: A

Rationale: Patent airway A is critical for survival, per document p20, .

Correct Answer: B

Rationale: Pyloric stenosis causes vomiting and hypochloremic alkalosis, per AAP. A, C-E differ.

Correct Answer: A

Rationale: Isolation of M. tuberculosis from culture is the gold standard for TB diagnosis, providing definitive evidence (CDC). Options B-E are supportive but less specific.

Correct Answer: C

Rationale: Air enema reduces intussusception, per AAP. A, B, D, E are secondary.

Correct Answer: B

Rationale: Hand-foot-mouth disease features vesicles in the mouth, hands, and feet, per CDC. A, C-E differ in distribution.

Correct Answer: B

Rationale: SLE fits rash, joint pain, and positive ANA/anti-dsDNA, per ACR. A, C-E lack serology.