Which condition is often associated with a "ground-glass" appearance on a chest x-ray in neonates?

Correct Answer: B

Rationale: The correct answer is B, Respiratory distress syndrome. Respiratory distress syndrome often presents with a "ground-glass" appearance on a chest x-ray in neonates due to surfactant deficiency. Choice A, Pneumonia, typically appears as patchy infiltrates on chest x-ray. Choice C, Bronchopulmonary dysplasia, is characterized by hyperinflation and fibrosis, not a ground-glass appearance. Choice D, Congenital diaphragmatic hernia, usually shows mediastinal shift and bowel loops in the chest cavity on x-ray, not a ground-glass appearance.

Correct Answer: A

Rationale: The correct answer is A, Patent ductus arteriosus. This condition is characterized by a continuous 'machine-like' murmur due to abnormal blood flow between the aorta and pulmonary artery. Ventricular septal defect (choice B) is characterized by a harsh holosystolic murmur, atrial septal defect (choice C) typically presents with a fixed split S2 and a pulmonary flow murmur, and coarctation of the aorta (choice D) is associated with a systolic murmur in the back and bilateral lower extremities.

Correct Answer: B

Rationale: The correct answer is B: Wheezing. Wheezing is a key distinguishing feature of bronchiolitis in infants, typically caused by respiratory syncytial virus (RSV) infection. Bronchiolitis is characterized by inflammation and mucus buildup in the small airways of the lungs, leading to wheezing sounds during breathing. Choices A, C, and D are incorrect because dry cough, stridor, and productive cough are not typical features of bronchiolitis in infants.

Correct Answer: B

Rationale: Hypokalemia is the correct answer because it is a common concern in children with severe diarrhea. Diarrhea can lead to significant potassium loss, resulting in hypokalemia. Hypernatremia (Choice A) is less common in diarrhea as sodium concentration is usually diluted by the fluid loss. Hypercalcemia (Choice C) is not typically associated with severe diarrhea. Hypomagnesemia (Choice D) can occur but is not as common as hypokalemia in this scenario.

Correct Answer: C

Rationale: Frequent spitting up is indeed a common symptom of gastroesophageal reflux in infants. It is caused by the backward flow of stomach contents into the esophagus, leading to infants regurgitating milk or formula shortly after feeding. Projectile vomiting (choice A) is more commonly associated with conditions like pyloric stenosis rather than gastroesophageal reflux. Bilious vomiting (choice B) often indicates an obstruction in the gastrointestinal tract. Diarrhea (choice D) is not typically a primary symptom of gastroesophageal reflux in infants.