Correct Answer: C

Rationale: Raising the patient's head and giving nothing by mouth is crucial in managing tracheoesophageal fistula. This intervention helps prevent aspiration and further complications until surgical correction can be performed. Feeding the neonate or suctioning could exacerbate the condition by risking aspiration. Elevating the head for feedings does not address the primary concern of preventing oral intake, making it less appropriate than the correct answer.

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 correct answer is B: Anorexia and malaise. The prodromal phase of acute viral hepatitis is characterized by nonspecific symptoms such as anorexia (loss of appetite) and malaise (general feeling of discomfort). These symptoms typically precede the more specific signs of jaundice, dark urine, and pale stools that manifest in the icteric phase. Choices A, C, and D are incorrect because bruising and lethargy, fatigability and jaundice, and dark urine and pale stools are typically seen in later stages of acute viral hepatitis, not in the prodromal phase.

Correct Answer: B

Rationale: The most appropriate action for a child with epistaxis is to pinch the nose and lean forward. This technique helps stop the bleeding and prevent aspiration of blood. By applying pressure to the bleeding vessels and allowing the blood to drain out of the nostrils instead of being swallowed, the risk of nausea and airway obstruction is reduced. Having the child lie flat (Choice A) may lead to blood flowing down the throat, causing potential choking. Applying a warm compress (Choice C) is not typically recommended for epistaxis as cold compresses are more effective. Encouraging deep breathing (Choice D) is not directly related to managing epistaxis.

Correct Answer: A

Rationale: The correct answer is A: Tetralogy of Fallot. Tetralogy of Fallot is often associated with a 'boot-shaped' heart appearance on a chest x-ray due to the characteristic heart anatomy in this condition. This appearance is caused by the combination of pulmonary stenosis, overriding aorta, ventricular septal defect, and right ventricular hypertrophy. Choice B, Transposition of the great arteries, is incorrect because it presents with a 'egg-on-a-string' appearance on x-ray due to the abnormal position of the aorta and pulmonary artery. Choice C, Coarctation of the aorta, typically presents with rib notching on x-ray. Choice D, Ventricular septal defect, does not produce the 'boot-shaped' heart appearance seen in Tetralogy of Fallot.