Which congenital heart defect causes a "boot-shaped" heart on a chest x-ray?

Correct Answer: A

Rationale: The correct answer is A: Tetralogy of Fallot. Tetralogy of Fallot, a congenital heart defect with four distinct abnormalities, often presents with a "boot-shaped" heart on chest x-ray due to right ventricular hypertrophy. This characteristic finding is due to the specific combination of defects in this condition. Coarctation of the aorta (choice B), Transposition of the great arteries (choice C), and Ventricular septal defect (choice D) do not typically result in a "boot-shaped" heart on a chest x-ray like Tetralogy of Fallot does.

Correct Answer: A

Rationale: Dry mucous membranes are a common sign of moderate dehydration in children, indicating a loss of bodily fluids. When a child is moderately dehydrated, the mucous membranes in the mouth and nose may appear dry. This condition can occur due to various factors such as vomiting, diarrhea, or inadequate fluid intake. Normal capillary refill (choice B) is not typically associated with dehydration; it is a measure of circulatory status. Hyperactive bowel sounds (choice C) can be present in conditions like gastroenteritis but are not specific to dehydration. Edema (choice D) is the retention of fluid in the body and is not a typical sign of dehydration.

Correct Answer: C

Rationale: The correct answer is C: Side-lying. The side-lying position is recommended after a tonsillectomy to facilitate drainage of secretions and reduce the risk of aspiration. This position helps prevent blood from pooling in the back of the throat, decreasing the chance of bleeding postoperatively. Supine (lying face up), while commonly used in other situations, may not be ideal immediately after a tonsillectomy due to the risk of airway obstruction from blood clots. Prone (lying face down) is not recommended as it can hinder breathing and increase the risk of complications. Fowler's position (semi-sitting) is also not typically used after a tonsillectomy because it may cause discomfort and hinder proper drainage.

Correct Answer: A

Rationale: The correct answer is A, Hepatitis B. The Hepatitis B vaccine is usually given at birth to protect against hepatitis B, a virus that can lead to chronic liver disease and liver cancer. This vaccination is crucial for newborns, especially those born to mothers who are carriers of hepatitis B. Choices B, C, and D are incorrect because DTaP (B), MMR (C), and Varicella (D) vaccines are not typically administered at birth. DTaP is given in a series starting at 2 months, MMR is usually given around 12-15 months, and Varicella is given between 12-15 months of age.

Correct Answer: B

Rationale: Rotavirus is the leading cause of acute gastroenteritis in children under 5 years. It leads to severe diarrhea and dehydration. Vaccination against rotavirus has significantly reduced the incidence of this disease, but it remains a major cause of morbidity in young children globally. Salmonella and Shigella can cause gastroenteritis, but they are less common in children under 5 years. Norovirus is also a common cause of gastroenteritis, but Rotavirus is the most prevalent in this age group.