Megacolon

Gladys Sudiyanto406118016

• Megacolon = large colon

Aetiology 1. Congenital2. Ulcerative colitis3. Poor toilet training

Congenital Megacolon or

Hirschprung’s disease

Pathology

• Absence of ganglion cells in the neural plexus of te intestinal wall

• Failure of migration of neuroblasts into the gut from vagal nerve trunks at the end of the first trimester of fetal life.

• Loss of ganglion cells extends for a variable distance above the anorectal junction.

The clinical features• vary from acute intestinal obstruction in neonates to

chronic constipation in later life.• Delayed passage of meconium beyond 24 hours• Abdominal distension• Chronic constipation starting in the first few weeks

of life. • The classic picture of gross abdominal distension,

chronic constipation and failure to thrive should be rare with a greater awareness of the diagnosis.

• Contracted rectal wall – felt during PR Examination• Rectal examination may provide a temporary relief

Investigations • Rectal biopsy – specimen are usually taken

fro just above the anorectal junction. One for biochemistry one for histochemistry (for acetylcholinseterase) and histopathology

• Anorectal manometry – rectosphincteric inhibitory reflex is absent

• Radiology – erect and supine abdominal radiographs. – distended loops of small and large intestines with gas and fluid levels consistent with a low intestinal obstruction.

Investigations

• An enema (Ba) using a water-soluble contrast medium will often confirm the diagnosis and indicate the lentgth and sixe of involved intestine. The contrast is instilled with a 5F catheter under screening control with the patient in the lateral position.- coing down of the transition zone, irregularity in the mucosa and abnormal conntractions of the intestie are important positive findings.

Treatment • Depends on age of the patient, the length of the involved

segment, the severity of symptoms and the presence of enterocolitis

• In the neonate : initial colostomy

• Short segment disease – an extended myectomy, removing a strip of rectal wall up to the area where normal gangilion cells start.

• Long segment disease – one of the four operations• Temporary colostomy for a few months – till the child

weighs 10 kg. the child will be between 10 months and 1 year of age and toilet training can usually start soon after the operation

• In some older children clear the retained faeces with enemas and laxatives – perform one-stage operation

Duhamal operation • Aganglionic segment is resected • Colon is brought behind the rectum and

anastomosed to it by a stapler• Swenson’s procedure• Coloanal anastomosis (Soave’s operation)

Reserved for older children, teenagers and adults

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Congenital megacolon

Hirschprung’s disease

Congenital megacolon

Hirscprung’s disease

Hirschprung’s disease