A Family Doctor's Tale - MEGACOLON

DOC I HAVE MEGACOLON

Megacolon is the dilatation and often hypertrophy of part or all the colon associated with constipation.

There is predominance of occurrence of 8 males to 1 female.

There is a familial history.

Two main causes  of Megacolon are

1.Congenital(also known as Hirsprung Disease)

The Congenital Megacolon occur in newborns due to the absence of autonomic ganglia from the distal segment of the colonic wall, varying in length(about 1 to 2 cm from rectosigmoid junction to entire colon).

Aganglionic colon provides a functional block to defecation, thus the colon proximal to the affected portion becomes grossly dilated and hypertrophied.

2.Acquired

a.Sliding megacolon:

The acquired idiopathic form is a functional disturbance of the colon in older children or adults resulting from persistent failure or inadequate rectal evacuation.

b.Paraesopphageal :

when the gastroesophageal junction is below the the diaphragm and part of the stomach herniates upwards along the esophagus.

The most common symptoms  of Megacolon are :

Congenital:

1.gross abdominal distension in severe cases

2.Constipation alternating with diarrhea due to bacterial overgrowth in milder cases

3.Respiratory distress may be present in infants due the pressure of the abdomen on the lung space.

4.weight loss

5.Rectum is usually empty on examination

Acquired:

1.Onset is slower with constipation

2.gross abdominal distension

3.Rectal examination shows a lax sphincter and full rectum

The Diagnosis of Megacolon is:

Megacolon is diagnosed through one or more medical tests:

Congenital:

1.lower gastrointestinal endoscopy.

Colonoscopy show presence of narrowed distal segment and transition to dilated part of colon.

2.colon biopsy showed neuronal lesion.

3.Rectosphincteric manometric studies show absence of anal sphincter response

Acquired:

1.colonoscopy showed gross rectal dilatation but no narrowed segment

2.colonic biopsy is normal

The Treatment of Megacolon is by:

The main treatment is :

Congenital:

1.colostomy may be required as a life saving measure

2.This is followed by later surgical resection of short segment or longer segment of the colon

Acquired:

1.Evacuation of impacted stools

2.suppositories or microenema to clear rectal feces daily

3.mild laxatives to help induce passing of stools

4.Retraining of toilet habits

The Complications of untreated Megacolon are:

1.dehydration in infants during severe gastroenteritis episodes

2.obstruction of the intestines

3.toxic megacolon

Prognosis of Megacolon is :

1. good to excellent in acquired form if treated medically

2.surgery is needed in the congenital form

Prevention in acquired megacolon is to

1.have good toilet and bowel habits .

2.Avoid constipation by taking more fruits and vegetables and fibre.

3.Enough physical exercise to help the intestine move easier.