Hirschprung’s Disease (Congenital Aganglionic Megacolon)

Fig. 32.1
Rectal biopsy showing ganglion cells
1.
Submucosa level (Meissner’s plexus)
 
2.
Myenteric level (Auerbach’s Plexus)
 
  • The lack of these ganglion cells leads to failure of the distal colon to relax which results in progressive functional constipation .
  • The disease can affect varying lengths of bowel segment.
  • In 75 % of cases, the rectosigmoid area is involved.
  • In 15–20 %, the aganglionosis extends variably to the rest of the colon.
  • In the most severe cases (5–10 %), the entire colon is affected. This condition is known as total colonic aganglionosis, or TCA.
  • In extremely rare cases, the entire intestinal tract (< 1 %) can be affected (total intestinal aganglionosis) .
  • Patients with HD are prone to develop enterocolitis .

      Etiology

      • The exact cause of HD is not known and several factors have been incriminated .
      • It is multifactorial, and can be familial or develop spontaneously.
      • The most accepted theory is that HD is due to a defect in the craniocaudal migration of enteric ganglia which are derived from the neural crest cells that occur during the first 12 weeks of gestation.
      • It is more common in boys than girls (male to female ratio: 3:1 or 4:1).
      • Family history in 3–7 % of cases.
      • There is increased risk for HD with affected sibling.
        1.
        Boys with sibling affected: 3–5 %.
         
        2.
        Girls with sibling affected: 1 %.
         
        3.
        The risk is substantially higher (12–30 %) in siblings of children with total colonic HD.
         
      • Eight genomes have been associated with HD. The predominantly affected gene is Ret-proto oncogene on chromosome 10q11.2 which affects 50 % of familial and 20 % of sporadic cases.
      • HD is associated with other chromosomal abnormalities and syndromes such as trisomy 21 and multiple endocrine neoplasia IIa (MEN IIa) .
      • Environmental factors, intrauterine intestinal ischemia, and infectious etiology have also been incriminated.

      Symptoms and Signs

      • Signs and symptoms of HD may vary with the severity of the condition .
      • Symptoms range from early presentation with neonatal intestinal obstruction to chronic progressive constipation in older children.
      • Approximately 80 % of patients present in the first few months of life with constipation, poor feeding, and abdominal distention (Fig. 32.2).
        A321246_1_En_32_Fig2_HTML.gif
        Fig. 32.2
        Clinical photograph of a patient with HD showing abdominal distension
      • Up to 90 % of infants with Hirschsprung’s disease fail to pass meconium in the first 24 h of life.
      • Signs and symptoms of neonatal presentation may include:
        • Failure to pass meconium within the first or second day of life
        • Poor feeding
        • Bilious vomiting
        • Infrequent, explosive bowel movements
        • Progressive abdominal distention
        • Poor weight gain
        • Enterocolitis-associated diarrhea
      • HD at other times may not be apparent until the baby becomes a teenager or rarely an adult.
      • Symptoms in older children include:
        • Chronic progressive constipation
        • Fecal impaction
        • Absence of soiling or overflow incontinence
        • Malnutrition
        • Failure to thrive
        • Abdominal distension
      • Patients may present with enterocolitis, a serious infection with diarrhea, fever and vomiting, and sometimes a dangerous dilatation of the colon .

      Enterocolitis

      • Enterocolitis is a serious infection that accounts for significant morbidity and mortality in patients with Hirschsprung’s disease .
      • Occurs in 10–30 % of infants with Hirschsprung’s disease.
      • It may occur in both the aganglionic and ganglionic segments of intestines and so it is seen both preoperatively and postoperatively.
      • Infants should continue to be monitored closely for enterocolitis many years after corrective surgery because the infection has been reported to occur up to 10 years postoperatively.
      • However, most postoperative enterocolitis cases occur within the first 2 years of pull-through.
      • Contrast enemas should be avoided in patients with enterocolitis because of the risk of perforation.
      • Symptoms of enterocolitis in patients with Hirschsprung’s disease include:
        • Abdominal distention
        • Foul-smelling, watery diarrhea
        • Lethargy, fever, vomiting, and poor feeding
      • Enterocolitis should be treated aggressively as it may lead to shock and death.
      • Treatment includes:
        • Nothing by mouth.
        • Rectal irrigation several times a day.
        • Antibiotics.
        • Oral metronidazole (Flagyl) can be used alone with rectal irrigation in patients with mild enterocolitis.
        • More severe cases should be treated with intravenous broad-spectrum antibiotics and rectal irrigation.
        • If there is no response, a diversion colostomy may become necessary .

      Associated Anomalies

      • Approximately 20 % of infants with HD will have one or more associated abnormality involving the neurological, cardiovascular, urological, or gastrointestinal system .
      • Down’s syndrome (trisomy 21) is the most common chromosomal abnormality associated with the disease, accounting for approximately 10 % of patients.
      • Hirschsprung’s disease has been found to be associated with the following syndromes and general anomalies:
        1.
        Down’s syndrome
         
        2.
        Neurocristopathy syndromes
         
        3.
        Waardenburg–Shah syndrome
         
        4.
        Yemenite deaf–blind syndrome
         
        5.
        Piebaldism
         
        6.
        Goldberg–Shprintzen syndrome
         
        7.
        Multiple endocrine neoplasia type II
         
        8.
        Congenital central hypoventilation syndrome (Ondine’s Curse)
         
      • Associated anomalies include :
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      Mar 8, 2017 | Posted by in PEDIATRICS | Comments Off on Hirschprung’s Disease (Congenital Aganglionic Megacolon)

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