ARANSI RILWAN A.

Introduction Epidemiology AetiopathogenesisPathophysiologyClinical features Management Complications Differential diagnosisConclusion

• Hirschsprung’s disease also called “Intestinal Aganglionosis”.

• Megacolon is a condition in which part or the whole of the intestine is hypertrophied, dilated and filled with faeces.

Their is congenital absence of parasympathetic ganglion cells normally found in the intermuscular and submucosalnerve plexus of the intestinal wall.

Incidence is 1 in 5000 births.

Four times as common in males

However, male preponderance almost disappears when aganglionosis extends beyond the recto-sigmoid area.

Congenital absence of ganglion cells normally found in the intermuscular and submucosal nerve plexus of the bowel wall in the distal bowel.

These ganglion cells coordinate muscular activity between the extrinsic & intrinsic inhibitory fibres.

The absence of enteric ganglion cells is

probably due to their failure to migrate

caudally from the vagal neural crest

between the 5th & 16th week of fetal life.

This abnormal innervation results in;

spasticity of the affected bowel segment

failure of coordinated peristaltic activity

results in functional obstruction to

evacuation of faeces.

The affected aganglionic segment may look normal or narrow,

merges proximally into a funnel-shaped transitional zone which contains only a few ganglia.

Above the transitional zone, the bowel is grossly hypertrophied from increased activity to propel faeces.

The pathophysiology of the disease is

not well understood.

The cause of the spasticity of the

aganglionic segment has not been

satisfactorily explained either.

Theories include;• Lack of modulatory influence of the ganglia causing imbalance

between the cholinergic motor and adrenergic inhibitory nerve activity

• Excessive cholinesterase activity coupled with an enhanced sensitivity of bowel muscle to Acetylcholine

• Deficiency of interstitial cells of Cajal (found in the plexuses and muscle layers, it generates slow waves in the GIT, act as pacemakers and control of gut contractions and motility

The aganglionosis usually starts at the internal

anal sphincter and then extends proximally to

Rectosigmoid area in about 75%

Splenic flexure or transverse colon in 17%

Whole colon or part of terminal ileum in 8%

Ultra short segment: below rectosigmoidjunction

Short segment: up to sigmoid colon

Long segment: up to splenic flexure or beyond

Total segment: affects whole colon.

The gross features of HD vary with duration of untreated disease

In the neonatal period, the intestine may appear fairly normal.

Classically there are 3 zones, macroscopically: 1.Dilated proximal intestine 2.Transition zone3.Distal undilated bowel

1. Proximal Dilated Bowel (Normoganglionic)

3. Contracted Distal Bowel(aganglionic)

2. Transition Zone (hypoganglionic)

DEPENDS ON AGE AT PRESENTATION• >80% are diagnosed in the neonatal period Delayed passage of meconium after birth

Constipation

Gross abdominal distention

Late onset of bilious vomiting

• In older infants Wasting

Failure to thrive

Distended abdomen

Chronic constipation

If complicated by enterocolitis• Infant may present paradoxically with diarrhoea

with profuse amount of offensive, loose watery

stool containing mucus or blood.

• If severe- fever, hypovolaemic shock

On examination• Gross abdominal distention, visible peristalsis,

flared ribs from abdominal distension causing a wide subcostal angle.

• Palpable faecal masses in the left flank

• On DRE, narrow, tight and empty anal canal with small amount of meconium or explosive mixture of flatus and faeces following DRE

HISTORY & EXAMINATION

INVESTIGATIONS

TREATMENT

Aim:

Confirm diagnosis

Optimize for treatment.

Plain abdominal radiograph:

show dilated loops of bowel with air-

fluid levels.

Occasionally, there may be a small

amount of air in the undistended rectum

and the dilated colon above it.

Barium Enema: Done on an unprepared colon

There should not have been a digital rectal examination or rectal washout for 3 days prior to the examination.

The enema will demonstrate the flow of barium from the undilated rectum through a funnel-shaped transitional zone into the proximal dilated colon.

Anorectal Manometry This demonstrates the failure of the internal anal

sphincter to relax when the rectum is distended - the recto-anal reflex

The pressure in the anal canal is not reduced on inflating the balloon in the rectum.

The test is reliable only in the older child

Biopsy Studies

Is the most accurate way of diagnosing Hirschsprung' s disease.

This biopsy is most often taken from the posterior wall of the rectum 1, 2, and 3cm above the dentate line under general anaesthesia.

The biopsy specimen should be full thickness, containing mucosa, submucosa and muscle wall.

FBC

Elecrtolyte, urea and creatinine

Grouping/ Cross-matching

• Depends on mode & age at presentation, length of the involved segment , severity of symptoms

Acute intestinal obstructionResuscitation

• IV LINE

• NG TUBE

• URETHRAL CATHETER

• BROAD SPECTRUM ANTIBIOTICS

A temporary colostomy is done

Site of colostomy should be as low as

possible in the ganglionated segment.

However, in the abscence of complications, a defunctioningcolostomy to prevent enterocolitis.

The colostomy is sited in normal bowel usually just above the transitional zone.

Definitive surgery is done when the infant is 10kg.

If a colostomy cannot be done or is unacceptable, regular saline rectal washouts until the infant is ready for definitive operation.

Older children

Definitive operation is performed in the

older child presenting for the first time if

there is no enterocolitis.

Definitive Operations

Swenson's OperationThe transitional zone is resected with the aganglionic segment and the normal bowel pulled down and anastomosed to a cuff of anus 2-3cm above the anal verge.

Duhamel's Operation

Soave's Operation

Intra op• Anaesthetic complications• Excessive hemorrhage

Post op• Anastomotic leak, stenosis, • Constipation,• Faecal incontinence, • Diarrhoea• Enterocolitis

Meconium ileus

Meconium plug syndrome

Atresias of the distal ileum and

proximal colon

Necrotising enterocolitis

Hypothyroidism

Principles and Practice of Surgical

Practice( Badoe).

The American Journal of

Gastroenterology(2005).

Bailey’s & Love’s Short Practice of

Surgery.