Health

Hirschsprung’s Disease | Congenital Agangalionic Megacolon

By March 11, 2017 No Comments
Hirschsprung’s Disease

Hirschsprung’s disease is the congenital absence of parasympathetic ganglion nerve cells in the intramuscular and submucosal plexuses of the intestinal tract usually within the distal ends of the colon, resulting in functional obstruction with dilatation and hypertrophy of proximal colon.

It is also called congenital a ganglionic mega colon.

Epidemiology of Hirschsprung’s Disease

The incidence of Hirschsprung’s disease is 1/5000 live births.

Male: female ratio 4:1, except in long segment disease 1:1, favoring females.

The most commonly affected site is the rectosigmoid colon 80% (short segment disease).

Long segment disease extends to the upper descending colon and transverse colon 10-20% and occasionally throughout the entire colon, involving the small bowel.

Causes of Hirschsprung’s Disease

An exact cause is unknown. It may result from failure of craniocaudal migration of the ganglion nerve cells go into the hindgut (an arrest in embryonic development affecting the migration of parasympathetic nerves of the intestine, occurring prior to the 12 weeks of gestation).

Risk Factors for Hirschsprung’s Disease

  1. Family members with the disease
  2. More common in males
  3. May be associated with other congenital defects like Down syndrome, congenital Heart disease etc.

Pathophysiology of Hirschsprung’s Disease

Failure of ganglion cells to migrate into the hindgut due to congenital arrest in embryonic development leads to no peristalsis in the affected portion of intestine which causes obstruction in the flow of stool through affected segment and the fecal matter and gases accumulate in the proximal normal segment of bowel causes distention intraluminal pressure increases, intraluminal pressure increased, which increases pressure on the bowel wall causes decreased blood flow and thus ischemia and deterioration of the mucosal barrier and internal rectal sphincter fails to relax and evacuation of fecal matter as well as gas and hence, sign and symptoms of abdominal distension, constipation may occur.

Clinical manifestations

Usually diagnosed in infancy (80% show symptoms in the first week of life), symptoms may differ with age and degree of bowel involvement.

In newborns: symptoms may appear at birth or within the first week of life

  • Failure to pass meconium within the first 48 hours of life
  • Vomiting- bile stained or fecal
  • Abdominal distention
  • Constipation- occurs in 100% of patients
  • Overflow type diarrhea
  • Dehydration; failure to thrive

In older children: symptoms may not be prominent at birth. Short –segment disease commonly present later.

  • History of constipation at birth
  • Progressive distention of abdomen
  • Ribbon-like, fluid-like, or pellet stools
  • Absence of encopresis
  • Diarrhea
  • Growth delay
  • Anemia
  • Enterocolitis

Enterocolitis: consists of severe toxemia and proliferation of bacteria in the colonic lumen

Diagnostic evaluation

Infancy (Most cases), some may not be diagnosed until adolescence or early adulthood.

  • Abdominal X-ray: distal intestinal obstruction, distention of abdomen, absence of gas in the rectum
  • Anorectal manometry: measurement of the pressures of the internal and external sphincter with a rectal balloon. It demonstrates the failure of the intestinal sphincter to relax in response to transient rectal distention.
  • Rectal biopsy: no ganglion cells in the submucosa
  • Barium enema: used to demonstrate a transition zone between the proximal dilated, normal innervated colon and the distal, narrow, aganglionic colon. May not be diagnostic in young infants.

Treatment and Therapeutic Management

Symptomatic Management

Older children with the mild and chronic disease until the physical status of children is improved.

  • Isotonic enema
  • Stool softeners
  • Low residue diet
  • High calorie and high protein diet
  • Intravenous fluid in severe condition

Neonate: with uncomplicated condition

  • Transverse Colostomy
  • In those patients whose aganglionic extends up to rectal-sigmoid function
  • If aganglionic extends more proximally then it is done in the most distal part of ganglion colon.

Neonate with complicated condition

  • Rapid resuscitation and emergency colostomy

Definitive treatment

Definitive treatment is the removal of aganglionic, nonfunctioning, dilated segment of the colon, followed by anastomosis and improved the functioning of the internal rectal sphincter.

  • After confirmation of diagnosis, initial surgery: A colostomy is performed to decompress intestine, divert fecal stream and rest the normal bowel.
  • After 9-12 months later, reanastomosis surgery is done which includes removal of agangalionic segment, pulling off the normal ganglionic colon above internal sphincter and anastomosis of the parts.
  • Different reconstructive techniques are:
  • Duhamel’s operation: retro rectal trans anal pull through creating a neorectum with aganglionic anterior wall and ganglionic posterior wall
  • Swenson’s operation: abdominal=–peritoneal pull through leaving the smallest amount of aganglionic bowel remaining.
  • Soave’s operation: endo-rectal pull through in which the ganglionic segment is pulled through the aganglionic muscular cuff, preserving the internal sphincter; may be done laparoscopically.

Complications

Preoperative

  • Enterocolitis: major cause of death
  • Hydro ureter or hydronephrosis
  • Water intoxication from tap water enemas
  • Cecal perforation

Postoperative

  • Enterocolitis remain the major cause of morbidity and mortality (mortality 6% to 30%)
  • Diarrhea, vomiting
  • Fever, lethargy
  • Abdominal distension
  • Fecal incontinence is common but can improve with a bowel regimen.

Prognosis

  • Most children of HD require surgery for treatment
  • The two-stage procedure has higher rate of success as it allows the child to regain nutritional status

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