Hirschsprung’s Disease

Congenital megacolon from failed migration of colonic ganglion cells during gestation — the affected distal bowel segment cannot relax, causing functional obstruction. Most commonly involves the rectosigmoid colon, but can affect the whole colon and (rarely) small intestine. See also constipation in childhood (red flags) and neonatal jaundice.

• Demographics: familial or sporadic; more common in boys. ~10% associated with Down syndrome; also linked to congenital deafness, hydrocephalus, bladder diverticulum, Meckel diverticulum, imperforate anus, VSD, renal agenesis, neuroblastoma, and Ondine’s curse (congenital central hypoventilation).
• Presentation: >80% present in the first few months with difficult bowel movements, poor feeding and progressive abdominal distension. 90% fail to pass meconium in the first 24 hours — though other causes need consideration too (meconium plug syndrome, CF-associated meconium ileus, anorectal malformation).

Symptoms

Infants	Older children
Bilious vomiting	Absence of soiling/overflow incontinence
Enterocolitis-associated diarrhoea	Chronic progressive constipation, onset in infancy
Failure to pass meconium in 24 hrs	Failure to thrive
Infrequent, explosive/difficult bowel movements	Faecal impaction
Jaundice	Malnutrition
Poor feeding/failure to thrive	Progressive abdominal distension
Progressive abdominal distension
Tight anal sphincter with an empty rectum

Diagnosis

Plain AXR can show dilated small bowel/proximal colon — but involve a specialist before arranging imaging if suspected on history/exam. Confirmed by rectal suction biopsy showing absent ganglion cells and hypertrophic nerve trunks.

Treatment

Surgery to bypass the affected segment, extent depending on disease length. Close follow-up for post-operative complications (anastomotic leak).

Complications

Enterocolitis is the most common and most serious complication — can progress to colonic rupture if untreated. Early signs: abdominal distension, foul-smelling watery stools, lethargy, poor feeding. Late signs: vomiting, fever, haematochezia, shock, death. Treated as an inpatient with rectal irrigation and antibiotics. Most treated patients do well — ~10% develop ongoing constipation, <1% faecal incontinence.

Counselling

Educate the family on a high-fibre diet and constipation/bowel-stasis prevention; counsel about the risk to siblings and early detection.