Correct Answer: B

Rationale: Clubbing of fingers is a common manifestation in children with tetralogy of Fallot due to chronic hypoxia. Clubbing occurs as a result of long-standing decreased oxygen levels in the blood, leading to changes in the fingertips. Slow respirations (Choice A) are not typically a direct clinical manifestation of tetralogy of Fallot. While decreased RBC counts (Choice C) may occur due to chronic hypoxia, they are not a primary manifestation specific to tetralogy of Fallot. Subcutaneous hemorrhages (Choice D) are not a common clinical manifestation associated with tetralogy of Fallot.

Correct Answer: B

Rationale: Rectal biopsy is the definitive diagnostic procedure for Hirschsprung disease in infants. This procedure reveals the absence of ganglion cells in the affected bowel segment, which is a hallmark of Hirschsprung disease. Colonoscopy (Choice A) is not typically used for diagnosing Hirschsprung disease due to the risk of not accurately reaching the affected segment. Multiple saline enemas (Choice C) are not used to confirm the diagnosis of Hirschsprung disease. Fiberoptic nasoenteric tube (Choice D) is not a standard diagnostic procedure for Hirschsprung disease and does not provide the necessary information to confirm the absence of ganglion cells in the affected bowel segment.

Correct Answer: D

Rationale: When caring for a child with acute laryngotracheobronchitis, the priority action should be to continually assess the respiratory status. This is crucial to detect early signs of respiratory distress, such as worsening stridor or increased work of breathing. Prompt intervention can prevent further deterioration of the child's condition. Initiating measures to reduce fever (Choice A) may be necessary but is not the priority in this situation. Ensuring delivery of humidified oxygen (Choice B) is important for maintaining oxygenation but should follow the assessment of respiratory status. Providing support to reduce apprehension (Choice C) is also important for the child's comfort but is not the priority over assessing and managing respiratory distress.

Correct Answer: A

Rationale: Infection is the most common cause of shock in infants and children due to their increased susceptibility to sepsis. Infants and children have underdeveloped immune systems, making them more prone to infections that can lead to septic shock. While cardiac failure is a serious condition, it is not the most common cause of shock in this population. Accidental poisoning, though dangerous, is less common than infection in causing shock in infants and children. Severe allergic reactions can lead to anaphylactic shock, but they are not as prevalent as infections in causing shock in this age group.

Correct Answer: A

Rationale: Right lower quadrant pain is a classic symptom of appendicitis. The appendix is typically located in the right lower quadrant of the abdomen, so pain in this area is commonly associated with appendicitis. Choices B, C, and D are incorrect because left lower quadrant pain, rebound tenderness, and epigastric pain are not typical manifestations of appendicitis. Left lower quadrant pain is not associated with appendicitis since the appendix is situated in the right lower quadrant. Rebound tenderness is more commonly linked with peritonitis rather than appendicitis. Epigastric pain is not a typical presentation of appendicitis as the pain is usually localized to the right lower quadrant.