What is the most common cause of bronchiolitis in infants?

Correct Answer: C

Rationale: The correct answer is C, Respiratory syncytial virus (RSV). RSV is the leading cause of bronchiolitis, a common respiratory condition in infants that results in inflammation of the small airways in the lung. It is highly contagious and can cause severe respiratory distress in young children, particularly those under 2 years old. Choice A, Adenovirus, is not the most common cause of bronchiolitis in infants. Choice B, Influenza virus, may cause respiratory infections but is not the primary cause of bronchiolitis. Choice D, Parainfluenza virus, can cause croup and other upper respiratory infections but is not the main cause of bronchiolitis in infants.

Correct Answer: B

Rationale: Constipation is the most common cause of abdominal pain in school-aged children. It is often due to dietary factors such as low fiber intake or insufficient fluid consumption. Chronic constipation can lead to complications like fecal impaction and soiling, highlighting the importance of early recognition and treatment. Gastroenteritis, although common, typically presents with diarrhea and vomiting. Appendicitis is more common in adolescents and typically presents with right lower quadrant pain. Irritable bowel syndrome is less common in children and is characterized by recurrent abdominal pain associated with defecation.

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: B

Rationale: The correct answer is B, Intravenous immunoglobulin (IVIG). IVIG is the primary treatment for Kawasaki disease, an acute vasculitis that mainly affects children under 5 years old. Early administration of IVIG is crucial as it helps reduce the risk of coronary artery aneurysms, which is the most serious complication of Kawasaki disease. Corticosteroids (Choice A) are not the primary treatment for Kawasaki disease and are not recommended due to potential adverse effects. Antibiotics (Choice C) are not indicated for the treatment of Kawasaki disease as it is not caused by a bacterial infection. Antivirals (Choice D) are also not part of the standard treatment for Kawasaki disease, as it is not caused by a viral infection.

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.