Which of the following best describes Hirschsprung disease?

Which of the following best describes Hirschsprung disease?

• A. Overgrowth of nerve cells in the colon
• B. Normal nerve supply with functional obstruction
• C. Nerve cells are missing from part or all of the colon, leading to impaired stool propulsion
• D. Inflammation of colonic mucosa

Answer: (C)

Hirschsprung disease is caused by congenital absence of enteric ganglion cells in the distal colon due to failure of neural crest cell migration. Without these ganglion cells (the Auerbach and Meissner plexuses), the affected segment cannot relax or generate peristalsis, creating a functional obstruction. Stool can’t move past the aganglionic segment, so it accumulates and proximal bowel becomes dilated (megacolon). This is why the best description is that nerve cells are missing from part or all of the colon, leading to impaired stool propulsion. Clinically, affected newborns may fail to pass meconium promptly and present with abdominal distension; diagnosis is by rectal biopsy showing absence of ganglion cells, and treatment involves surgically removing the aganglionic segment. The other descriptions don’t fit: overgrowth of nerve cells would not cause obstruction; normal nerve supply with a functional blockage contradicts the lack of innervation; and inflammatory mucosal disease describes a different process altogether.

Hirschsprung disease is caused by congenital absence of enteric ganglion cells in the distal colon due to failure of neural crest cell migration. Without these ganglion cells (the Auerbach and Meissner plexuses), the affected segment cannot relax or generate peristalsis, creating a functional obstruction. Stool can’t move past the aganglionic segment, so it accumulates and proximal bowel becomes dilated (megacolon). This is why the best description is that nerve cells are missing from part or all of the colon, leading to impaired stool propulsion. Clinically, affected newborns may fail to pass meconium promptly and present with abdominal distension; diagnosis is by rectal biopsy showing absence of ganglion cells, and treatment involves surgically removing the aganglionic segment. The other descriptions don’t fit: overgrowth of nerve cells would not cause obstruction; normal nerve supply with a functional blockage contradicts the lack of innervation; and inflammatory mucosal disease describes a different process altogether.