Disorders of the Lower Bowel - Hirschsprung Disease

Hirschsprung Disease

Definition

Hirschsprung disease is a condition characterized by the absence of nerve cells in a section of the bowel, typically the lower sigmoid colon. This lack of nerve cells disrupts normal bowel movement (peristalsis), preventing stool from moving through the affected part of the intestine.

Description

Hirschsprung disease involves the absence of ganglionic innervation to the muscle of a section of the bowel, frequently the lower portion of the sigmoid colon just above the anus (Brumbaugh et al., 2020). This condition is also known as aganglionic megacolon. The absence of nerve cells results in the lack of peristaltic waves in the affected segment, hindering the movement of fecal material. This leads to chronic constipation or ribbon-like stools, where stools passing through the narrow segment appear like ribbons. Consequently, the bowel proximal to the obstruction dilates, causing abdominal distension.

Symptoms

  • Chronic constipation

  • Ribbon-like or pellet-shaped stools

  • Abdominal distension

  • Children may appear thin and undernourished

  • Inability to pass meconium

  • Palpable fecal mass

Etiology and Incidence

The etiology of Hirschsprung disease involves an abnormal gene on chromosome 10. It is more common in males and siblings of children with the condition. The incidence is approximately 1 in 5,000 live births.

Diagnostic Tests

  • Digital Rectal Exam: In typical constipation, a finger insertion reveals hard stool. However, in Hirschsprung disease, the rectum is empty due to the obstruction.

  • Barium Enema or UTZ: These imaging tests highlight the narrow, nerve-less portion of the bowel and the dilated section above it. Caution: Enemas must be administered carefully as the child cannot expel them easily.

  • Rectal Biopsy: This definitive test involves a biopsy of the affected bowel segment to check for the absence of nerve cells.

  • Anorectal Manometry: Measures the pressure exerted by the internal rectal sphincter to assess its function and innervation.

Treatment

The primary treatment for Hirschsprung disease is surgery.

  • Surgery: The affected bowel section is removed, and the intestine is reconnected (pull-through operation).

  • Two-Stage Surgery:

    • Stage 1: A temporary colostomy is performed.

    • Stage 2: Bowel repair is conducted after 12-18 months.

    • Post-surgery, the child typically regains normal bowel function. If bowel function does not return, a permanent colostomy may be necessary.