**Question:** Most common cause of hematochezia in children is

A. Hirschsprung's disease
B. Meckel's diverticulum
C. Inflammatory bowel disease (IBD)
D. Fecal impaction

**Correct Answer:** D. Fecal impaction

**Core Concept:** Hematochezia refers to the presence of blood in the stool, which can be caused by various gastrointestinal disorders in children.

**Why the Correct Answer is Right:** Fecal impaction is a common cause of hematochezia in children. It occurs when stool becomes compacted and difficult to pass due to constipation, leading to mucosal irritation and bleeding. This can result in visible blood in the stool (hematochezia).

**Why Each Wrong Option is Incorrect:**

A. Hirschsprung's disease: This is a congenital disorder affecting the enteric nervous system, causing absent or poorly developed ganglion cells in the submucosa of the large intestine. While it can lead to bleeding, it is less likely to cause hematochezia due to its specific anatomical location and the presence of ganglion cells.

B. Meckel's diverticulum: A Meckel's diverticulum is a congenital remnant of the embryonic midgut and can cause bleeding, but it is less common than fecal impaction as a cause of hematochezia in children.

C. Inflammatory bowel disease (IBD): IBD includes Crohn's disease and ulcerative colitis. While IBD can cause bleeding and hematochezia, it is less common than fecal impaction as a cause of hematochezia in children. Additionally, IBD generally presents with more severe gastrointestinal symptoms and complications.

**Clinical Pearl:** It is essential for clinicians to consider fecal impaction when assessing children with hematochezia, as it is a common and treatable cause. Diagnosis can be confirmed with rectal examination or digital rectal examination, which may reveal the impacted stool mass. Treatment involves manual evacuation of the impacted stool and addressing the underlying constipation in children.