Hirschsprung’s disease involves which region of intestine: March 2005
**Core Concept**
Hirschsprung's disease is a congenital condition characterized by the absence of **ganglion cells** in the distal bowel, leading to a functional obstruction. This condition is related to the development of the **enteric nervous system**. The primary issue is the lack of **peristalsis** in the affected segment.
**Why the Correct Answer is Right**
The correct answer involves the region of the intestine that is typically affected by Hirschsprung's disease. The disease usually involves the **rectosigmoid** region, where the absence of ganglion cells causes a failure of the muscle to relax, resulting in a narrowing of the intestinal lumen. This narrowing leads to an obstruction, causing significant **constipation** and other symptoms.
**Why Each Wrong Option is Incorrect**
**Option A:** This is incorrect because Hirschsprung's disease does not typically involve the entire intestine.
**Option B:** This option is also incorrect as the disease primarily affects the distal bowel.
**Option D:** This is incorrect because the disease usually spares the small intestine.
**Clinical Pearl / High-Yield Fact**
A key point to remember is that Hirschsprung's disease presents with **failure to pass meconium** within the first 48 hours of life, along with abdominal distension and vomiting.
**Correct Answer:** D. Rectosigmoid region