Which pediatric condition is characterized by a "string sign" on an upper GI series?

Correct Answer: B

Rationale: The correct answer is B: Hypertrophic pyloric stenosis. The "string sign" is associated with hypertrophic pyloric stenosis, a condition where the pyloric canal is narrowed, leading to gastric outlet obstruction. Intussusception (choice A) typically presents with colicky abdominal pain and currant jelly stools. Hirschsprung disease (choice C) is characterized by the absence of ganglion cells in the distal colon. Meckel diverticulum (choice D) is a congenital outpouching of the small intestine that can present with painless rectal bleeding.

Correct Answer: B

Rationale: The primary concern with untreated vesicoureteral reflux (VUR) in pediatric patients is chronic renal failure. Untreated VUR can lead to this complication due to recurrent urinary tract infections and kidney damage. While recurrent UTIs (Choice A) are a common consequence of VUR, the ultimate worry is the development of chronic renal failure. Hypertension (Choice C) may occur as a result of renal damage but is not the primary concern. Bladder dysfunction (Choice D) is not the most significant consequence of untreated VUR in terms of long-term outcomes compared to chronic renal failure.

Correct Answer: A

Rationale: Respiratory infections are the leading cause of morbidity and mortality in children with cystic fibrosis. Cystic fibrosis primarily affects the respiratory system, leading to thick mucus buildup in the lungs, which predisposes these children to recurrent respiratory infections. Malnutrition and diabetes are common comorbidities in cystic fibrosis but are not the leading causes of morbidity and mortality in affected children. Liver disease can occur in cystic fibrosis but is less common than respiratory complications.

Correct Answer: B

Rationale: "Currant jelly" stools, consisting of mucus and blood, are characteristic of intussusception in children. It occurs due to the telescoping of a segment of the intestine into an adjacent segment, leading to obstruction and subsequent mucosal ischemia, causing the passage of bloody mucus in the stool. Bilious vomiting can be seen in other conditions like bowel obstruction, abdominal distention can be present but is not as specific, and constipation is less likely in the presentation of intussusception.

Correct Answer: A

Rationale: The correct answer is A: Strawberry tongue. In Kawasaki disease, a 'strawberry tongue' is most indicative of the acute phase. This refers to the tongue appearing red and swollen with enlarged fungiform papillae, giving it a strawberry-like appearance. Joint pain (Choice B) is more commonly associated with other conditions like rheumatoid arthritis. Rash (Choice C) and peeling skin (Choice D) are also seen in Kawasaki disease but are not as specific to the acute phase as the presence of a strawberry tongue.