Congenital Aganglionic Megacolon

Question 1

Definition

Answer 1

• Functional obstruction of the colon due to absence of ganglion cells in bowel wall

• Commonest site: rectosegmoid in 75%
. 10% of cases total —->ileostomy

Question 2

Incidence

Answer 2

• 1 / 5000

* Male: Females = 4: 1 (positive family history may be present).

Question 3

Clinical picture/Presentation

Answer 3

Neonatal (80%):
Delayed passage of meconium beyond 48 hours.

• May be acute obstruction

In older child:
Chronic constipation and abdominal distension.

• Large fecal mass felt in left lower abdomen with empty rectum

Question 4

Clinical picture/

Complicated cases:

Answer 4

🌚„ Enterocolitis:

• Infection with clostridia difficile, staph aureus and anaerobes
• Presented with bloody diarrhea & toxemia

🌚 Intermittent attacks of intestinal obstruction.

🌚 Failure to thrive due to protein losing enteropathy

Question 5

Investigations

Answer 5

🌚🌝contrast enema
Barium enema:→ olderthen 1m
Gastrographin → younger then 1m

• Classic findings: an abrupt narrow transition zone between the normal dilated proximal colon and a smaller caliber obstructed distal aganglionic segment

🌚🌝 Rectal suction biopsy (from narrow segment)
• The gold standard for diagnosing Hirschsprung disease
• Reveals absent ganglia + hyper trophid neve endings

Question 6

TX

Answer 6

pull-through procedure: surgical resection of aganglionic intestinal segment and anastomosis of remaining intestine to anus Either in newborn period or staged if extensive aganglionosis

Question 7

Prognosis

Answer 7

Most have normal/ near-normal anorectal function Complications: fecal incontinence and constipation, postoperative enterocolitis (medical emergency if progresses to sepsis)