What is a causative factor of Hirschsprung disease?

Correct Answer: C

Rationale: The correct answer is C: Absence of parasympathetic ganglion cells in a portion of the colon. Hirschsprung disease is a congenital condition characterized by the absence of nerve cells (ganglia) in parts of the colon. This absence leads to a lack of peristalsis in the affected segment, resulting in severe constipation and bowel obstruction. Choices A, B, and D are incorrect. Choice A describes symptoms of diarrhea rather than a causative factor of Hirschsprung disease. Excessive peristaltic movement (choice B) is not a causative factor but rather the opposite, as Hirschsprung disease is associated with reduced peristalsis. Choice D, which refers to intussusception, is a different condition unrelated to Hirschsprung disease.

Correct Answer: B

Rationale: Children with a history of severe allergic reactions should receive inactivated vaccines because they do not contain live pathogens. Live attenuated vaccines (choice A) contain weakened live pathogens and can potentially trigger an allergic reaction in sensitive individuals. Subunit vaccines (choice C) and recombinant vaccines (choice D) may contain components that could still trigger an allergic response in individuals with a history of severe allergies. Inactivated vaccines are the safest choice for individuals with a history of severe allergic reactions as they do not pose a risk of causing an allergic reaction due to the absence of live pathogens.

Correct Answer: B

Rationale: The correct first step in managing a child with a suspected head injury is to assess the child's level of consciousness. This assessment is crucial as it helps determine the severity of the injury and guides further management. Administering pain medication (Choice A) should not be done before assessing the level of consciousness. Performing a CT scan (Choice C) may be necessary but is not the initial step. Monitoring for seizures (Choice D) is important but comes after assessing the child's level of consciousness.

Correct Answer: D

Rationale: The correct answer is D, Fever. In young children, fever is a common primary symptom of a urinary tract infection, often accompanied by irritability and discomfort. Frequent urination (Choice A) is a symptom more commonly seen in adults with UTIs. While abdominal pain (Choice B) and vomiting (Choice C) can be present, they are not as primary as fever in young children with UTIs.

Correct Answer: A

Rationale: The correct answer is fats. Fats provide 9 kilocalories per gram, which is more energy-dense compared to proteins and carbohydrates. While proteins and carbohydrates provide 4 kilocalories per gram, fats provide more than twice the energy, making them the most energy-providing nutrient. Alcohols are not considered essential nutrients and do not provide energy for the body, unlike fats, proteins, and carbohydrates. Therefore, fats are the correct answer for the most energy-providing nutrient.