Overview
Definition:
Hirschsprung disease (congenital aganglionic megacolon) is a congenital disorder characterized by the absence of ganglion cells in the myenteric (Auerbach) and submucosal (Meissner) plexuses of a segment of the colon, leading to functional obstruction.
Epidemiology:
It affects approximately 1 in 5000 live births
The male-to-female ratio is approximately 4:1
Associated with genetic syndromes such as Down syndrome (trisomy 21) in up to 10% of cases.
Clinical Significance:
Hirschsprung disease is a critical cause of neonatal intestinal obstruction and requires prompt diagnosis and surgical management to prevent life-threatening complications like enterocolitis and sepsis
Understanding its pathophysiology and management is crucial for pediatricians and surgeons preparing for DNB and NEET SS exams.
Clinical Presentation
Symptoms:
Failure to pass meconium within 24-48 hours of birth
Abdominal distension
Bilious vomiting
Constipation
Poor feeding
Growth failure
Explosive stools after digital stimulation
Palpable fecal mass
Rectal examination may reveal an empty rectum with a tight anal sphincter and, upon withdrawal, a forceful expulsion of gas and stool (squirt sign or blast sign).
Signs:
Abdominal distension
Visible bowel loops
Tenderness
Fever (suggestive of enterocolitis).
Diagnostic Criteria:
Diagnosis is primarily based on a combination of clinical suspicion, radiological findings, and definitive histological confirmation of absent ganglion cells in a full-thickness rectal biopsy
Genetic testing may be considered in suspected syndromic cases.
Diagnostic Approach
History Taking:
Detailed birth history (gestational age, events)
Feeding history and weight gain
Bowel habit history (frequency, consistency, difficulty with defecation)
Any episodes of vomiting or abdominal distension
Family history of Hirschsprung disease or other gastrointestinal anomalies.
Physical Examination:
General assessment of hydration and distress
Abdominal examination for distension, tenderness, palpable masses, and bowel sounds
Digital rectal examination to assess anal tone, rectal vault emptiness, and presence of the squirt sign.
Investigations:
Abdominal X-ray: May show dilated loops of bowel proximal to an aganglionic segment and a narrow distal segment, but often non-specific
Contrast enema (barium or water-soluble contrast): Shows a narrowed distal aganglionic segment with dilated proximal bowel and an abrupt transition zone
Rectal manometry: Assesses anal sphincter relaxation response to rectal distension (normally present
absent in Hirschsprung disease)
Rectal biopsy (full-thickness or suction): Gold standard for diagnosis
demonstrates absence of ganglion cells in the submucosal and myenteric plexuses and presence of hypertrophied nerve fibers
Biopsy should be taken from adequate depth to include the submucosa.
Differential Diagnosis:
Meconium ileus (often associated with cystic fibrosis)
Intestinal atresia or stenosis
Malrotation with volvulus
Intestinal duplication cysts
Functional constipation
Imperforate anus.
Management
Initial Management:
If suspected neonatally, immediate decompression of the abdomen with a rectal tube or nasogastric tube
Fluid and electrolyte management
Antibiotics if enterocolitis is suspected.
Surgical Management:
Definitive treatment is surgical
The goal is to resect the aganglionic bowel and restore bowel continuity by connecting the normally innervated bowel to the anus
Procedures include: 1
Swenson pull-through: Total colectomy with rectosigmoid resection and coloanal anastomosis
2
Soave endorectal pull-through: Aganglionic mucosa is dissected off the muscularis externa, and normally innervated bowel is pulled through the muscular sleeve and anastomosed to the anus
3
Duhamel pull-through: Posterior rectosigmoid resection with a side-to-side pull-through anastomosis of the ganglionic bowel to the anus, leaving the muscular cuff of the aganglionic segment
A temporary diverting colostomy is often performed in neonates to decompress the bowel and allow for bowel preparation before the pull-through procedure.
Supportive Care:
Postoperative care involves pain management, intravenous fluids, gradual reintroduction of oral feeds, and monitoring for complications such as anastomotic leak, infection, and enterocolitis
Long-term management may include bowel irrigation and stool softeners.
Complications
Early Complications:
Anastomotic leak
Wound infection
Sepsis
Enterocolitis (can be life-threatening)
Bowel obstruction
Stenosis at the anastomosis.
Late Complications:
Persistent constipation or encopresis
Recurrent enterocolitis
Rectal prolapse
Sexual dysfunction
Stricture formation at the anastomosis.
Prevention Strategies:
Adequate bowel preparation before pull-through surgery
Careful surgical technique to ensure complete resection of aganglionic bowel and a tension-free anastomosis
Prompt recognition and management of enterocolitis
Appropriate postoperative care and follow-up.
Prognosis
Factors Affecting Prognosis:
Length of the aganglionic segment (shorter segment generally has better outcomes)
Presence of associated anomalies or syndromes (e.g., Down syndrome)
Promptness and adequacy of surgical treatment
Management of postoperative complications, particularly enterocolitis
Quality of postoperative care and follow-up.
Outcomes:
With timely diagnosis and surgical intervention, most children achieve satisfactory bowel control and good quality of life
However, some may experience chronic constipation, soiling, or recurrent enterocolitis
The success rates of pull-through procedures are generally high, with over 90% of patients achieving good to excellent functional results.
Follow Up:
Regular follow-up is essential to monitor bowel function, detect early signs of complications (especially enterocolitis and anastomotic strictures), and provide ongoing support for bowel management
This includes physical examinations, assessment of bowel habits, and periodic rectal irrigations if needed.
Key Points
Exam Focus:
The definition and pathophysiology of Hirschsprung disease (absence of ganglion cells)
The diagnostic triad: clinical suspicion, contrast enema findings (transition zone), and rectal biopsy confirmation (gold standard)
Common surgical procedures (Swenson, Soave, Duhamel) and the role of a diverting colostomy
Management of enterocolitis as a critical complication.
Clinical Pearls:
Always consider Hirschsprung disease in a neonate failing to pass meconium
Rectal biopsy must be full-thickness and include submucosa
The squirt sign is a helpful bedside clue
Enterocolitis is a surgical emergency requiring prompt decompression and antibiotics.
Common Mistakes:
Inadequate rectal biopsy technique leading to false-negative results
Delaying surgery in symptomatic neonates
Inadequate bowel preparation before pull-through
Underestimating the severity and risk of enterocolitis
Failing to counsel parents about potential long-term bowel management challenges.