Makindo Medical Notes

Hirschsprung's disease is a congenital disorder characterized by the absence of nerve cells in the muscles of part or all of the large intestine, leading to severe constipation or intestinal obstruction. Early diagnosis and surgical intervention are crucial for preventing life-threatening complications and ensuring normal growth and development in affected infants.

About

• Hirschsprung's Disease is a congenital condition characterized by the absence of myenteric ganglion cells in the distal bowel wall, leading to functional bowel obstruction.
• Also known as congenital megacolon, it affects approximately 1 in 5000 live births.

Associations

• Family history of Hirschsprung's disease.
• Genetic Conditions: Neurofibromatosis, Down syndrome, Waardenburg's syndrome, Multiple endocrine neoplasia type IIA.
• Congenital Anomalies: Ventricular septal defect (VSD), renal agenesis.

Pathology

• Hirschsprung's disease results from the failure of neural crest cells to migrate to the distal bowel during fetal development.
• The absence of parasympathetic ganglion cells in the myenteric (Auerbach's) plexus leads to failure of bowel relaxation, causing functional obstruction.
• Due to the lack of peristalsis, the aganglionic segment remains constricted, and the proximal bowel becomes dilated and hypertrophic, leading to megacolon.

Aetiology

• 70% of cases involve the rectosigmoid colon
• 20% involve the entire colon
• 10% may extend into the small intestine.
• The aganglionic bowel lacks peristalsis and passively constricts, creating a mechanical obstruction.

Clinical Features

• Infants typically appear healthy at birth but then fail to pass meconium within the first 24-48 hours of life.
• Symptoms include abdominal distension, bloating, vomiting, poor feeding, and progressive constipation.
• Milder cases may present later in infancy or childhood with chronic constipation.
• Hirschsprung's Enterocolitis: A serious complication, characterized by severe distension, fever, and diarrhoea, and can be life-threatening if not treated promptly.

Differential Diagnoses

• Functional constipation.
• Meconium ileus (associated with cystic fibrosis).
• Imperforate anus.
• Neonatal sepsis.
• Intestinal atresia.

Investigations

• Laboratory Tests:
  • Complete Blood Count (CBC): To check for anemia, which may suggest chronic bleeding from erosive esophagitis.
  • Urea & Electrolytes (U&E): To assess overall metabolic status.
  • Liver Function Tests (LFTs): To rule out hepatic causes of symptoms.
  • C-Reactive Protein (CRP): To detect inflammation.
  • Blood Glucose: To screen for diabetes mellitus.
  • Osmolality: Particularly in cases with suspected diabetes insipidus.
• Pituitary Function Tests: Cortisol, Growth Hormone (GH), Thyroid Function Tests (TFT), Prolactin (PRL), estrogen, testosterone.
• Short Synacthen Test: To assess adrenal gland function if indicated.
• Imaging Studies:
  • Barium Swallow: An X-ray imaging technique where the patient swallows barium to visualize the esophagus and stomach, identifying herniation and assessing swallowing function.
  • Oesophagogastroduodenoscopy (OGD): Endoscopic examination to visualize the esophagus, stomach, and duodenum, identifying esophagitis, hiatus hernia, Barrett's oesophagus, or malignancies.
  • Magnetic Resonance Imaging (MRI) or Computed Tomography (CT) Scan: Provides detailed anatomical visualization if needed.
• Rectoanal Manometry: Balloon distension of the rectum fails to trigger internal anal sphincter relaxation, indicative of Hirschsprung's disease.
• Rectal Biopsy: The definitive diagnostic test, showing the absence of ganglion cells and the presence of hypertrophic nerve trunks. The biopsy should be taken at least 1.5 cm above the dentate line, as the distal rectum naturally lacks ganglion cells.
• Visual Field Testing (Perimetry): Performed if there is concern about visual defects due to optic chiasm compression.

Management

• Initial Management:
  • If enterocolitis or other serious symptoms develop, perform a colostomy in healthy bowel to stabilize the patient until definitive surgery can be performed.
  • Bowel Decompression: Serial rectal irrigations may be used before surgery to decompress the bowel and prevent enterocolitis.
• Surgical Intervention:
  • Swenson's Procedure: The classic surgery, where the aganglionic segment of the rectum is resected, and the healthy ganglionated colon is pulled through and connected to the anus.
  • Soave Procedure: Involves removing the mucosal and submucosal layers of the aganglionic segment while preserving the muscular layer.
  • Duhamel Procedure: Connects the ganglionated colon to the anus in a side-to-side fashion, creating a side pouch to facilitate bowel movements.
• Postoperative Care:
  • Monitoring for complications such as anastomotic leaks, infection, and enterocolitis.
  • Gradual reintroduction of oral feeding once bowel function is restored.
  • Management of any ongoing hormonal deficiencies if present.
• Long-Term Management:
  • Post-surgery, bowel function may remain imperfect for several years, and some children may experience constipation or incontinence. Regular follow-up is necessary to monitor bowel function and address complications.
  • Psychological support and counseling may be beneficial for children and families dealing with chronic conditions.

Prognosis

The prognosis for individuals with Hirschsprung's disease is generally favorable with appropriate surgical intervention and postoperative care. Early diagnosis and treatment are crucial for preventing life-threatening complications and ensuring normal growth and development in affected children.

• Surgical Outcomes:
  • Successful resection of the aganglionic segment can restore normal bowel function.
  • Some patients may experience postoperative complications such as enterocolitis, anastomotic leaks, or strictures.
• Long-Term Outcomes:
  • Most children adapt well and achieve normal bowel movements after surgery.
  • Some may continue to experience mild to moderate constipation or incontinence, requiring ongoing management.
  • Early intervention improves overall outcomes and quality of life.
• Complications:
  • Hirschsprung's enterocolitis is a severe and potentially life-threatening complication that requires immediate medical attention.
  • Chronic issues such as constipation and incontinence can affect growth and development if not properly managed.

Conclusion

Hirschsprung's disease is a congenital disorder that can lead to severe bowel obstruction and significant health complications if not diagnosed and treated promptly. Comprehensive diagnostic evaluations, including rectal biopsy, are essential for accurate diagnosis. Surgical intervention remains the cornerstone of management, with various surgical techniques available to remove the aganglionic segment and restore normal bowel function. Long-term follow-up and management of potential complications are crucial for ensuring optimal outcomes and improving the quality of life for affected individuals.

References

• Hirschsprung's Disease: Diagnosis and Management
• Mayo Clinic. Hirschsprung's Disease. Available at: https://www.mayoclinic.org
• World Health Organization (WHO). Hirschsprung's Disease. Available at: https://www.who.int
• Bailey, S. J., & Demehri, S. (2016). Hirschsprung Disease. In Pediatric Gastrointestinal Disorders (pp. 277-298). Springer.
• Stolte, M. J., & Van der Gaag, N. A. (2018). Hirschsprung's Disease. In Neonatology (pp. 675-682). Elsevier.
• American Academy of Pediatrics. Hirschsprung Disease. Available at: https://www.aap.org