Hirschsprung Disease in Children
Introduction to Hirschsprung Disease in Children
Hirschsprung disease (HD) is a congenital disorder of the enteric nervous system that affects the gastrointestinal tract, primarily in children. It is characterized by the absence of ganglion cells in the myenteric and submucosal plexuses of the distal colon, resulting in functional obstruction.
Key Points:
- Incidence: Approximately 1 in 5,000 live births
- Male predominance: 4:1 male to female ratio
- Genetic component: Associated with mutations in the RET proto-oncogene and other genes
- Variable extent: Can affect varying lengths of the colon, from the rectum to the entire colon
- Primary symptom: Delayed passage of meconium in newborns (>48 hours after birth)
- Diagnosis: Combination of clinical presentation, imaging studies, and rectal biopsy
- Treatment: Surgical intervention is required to remove the aganglionic segment
- Long-term management: Ongoing follow-up for potential complications and bowel function
Etiology of Hirschsprung Disease
Hirschsprung disease results from a developmental disorder of the enteric nervous system. The primary causes and risk factors include:
- Genetic factors:
- Mutations in the RET proto-oncogene (found in 50% of familial cases and 15-35% of sporadic cases)
- Other genes implicated: EDNRB, EDN3, SOX10, PHOX2B, and GDNF
- Associated with Down syndrome, Waardenburg syndrome, and other genetic disorders
- Embryological defect: Failure of neural crest cells to migrate properly during fetal development (weeks 5-12 of gestation)
- Family history: 3-8% of cases have a familial component
- Environmental factors: Some studies suggest a role for maternal factors such as diet and medication use during pregnancy
Clinical Presentation of Hirschsprung Disease
The presentation of Hirschsprung disease can vary depending on the extent of aganglionosis and the age of the child:
- Neonatal period:
- Delayed passage of meconium (>48 hours after birth)
- Abdominal distension
- Bilious vomiting
- Failure to thrive
- Infancy and early childhood:
- Chronic constipation
- Abdominal distension
- Poor feeding
- Failure to thrive
- Enterocolitis (in severe cases)
- Older children and adolescents:
- Chronic constipation
- Abdominal pain
- Malnutrition
- Growth delay
Diagnosis of Hirschsprung Disease
Diagnosis of Hirschsprung disease involves a combination of clinical evaluation, imaging studies, and histological examination:
- Clinical history and physical examination:
- Delayed passage of meconium
- Abdominal distension
- Empty rectal vault on digital rectal examination
- Imaging studies:
- Contrast enema: Shows transition zone between dilated proximal colon and narrowed distal segment
- Abdominal X-ray: May show dilated bowel loops and absence of rectal gas
- Anorectal manometry: Reveals absence of rectoanal inhibitory reflex
- Rectal biopsy: Gold standard for diagnosis
- Suction rectal biopsy: For infants and young children
- Full-thickness biopsy: For older children or inconclusive suction biopsies
- Histological findings: Absence of ganglion cells and presence of hypertrophied nerve fibers
- Genetic testing: May be performed to identify associated genetic mutations and for genetic counseling
Treatment of Hirschsprung Disease
The primary treatment for Hirschsprung disease is surgical intervention to remove the aganglionic segment of the bowel:
- Preoperative management:
- Bowel decompression using rectal irrigations or colonic lavage
- Nutritional support
- Treatment of enterocolitis, if present
- Surgical options:
- Transanal endorectal pull-through (TEPT): Minimally invasive procedure suitable for short-segment disease
- Duhamel procedure: Creates a side-to-side anastomosis between the ganglionic and aganglionic segments
- Swenson procedure: Involves complete resection of the aganglionic segment and anastomosis of ganglionic bowel to the anus
- Soave procedure: A modified pull-through technique that preserves the outer muscular cuff of the rectum
- Timing of surgery:
- Single-stage procedure: Often performed in neonates or young infants
- Multi-stage procedure: May be necessary for long-segment disease or in the presence of complications
- Postoperative care:
- Anal dilatations to prevent stricture formation
- Bowel management program
- Nutritional support
Complications of Hirschsprung Disease
Hirschsprung disease can lead to several complications, both before and after treatment:
- Preoperative complications:
- Enterocolitis: Inflammation of the bowel, potentially life-threatening
- Toxic megacolon: Severe dilatation of the colon with systemic toxicity
- Intestinal perforation
- Malnutrition and failure to thrive
- Postoperative complications:
- Anastomotic leak or stricture
- Recurrent enterocolitis
- Fecal incontinence
- Chronic constipation
- Adhesive small bowel obstruction
- Long-term issues:
- Bowel function problems (constipation or incontinence)
- Growth and developmental delays
- Psychosocial issues related to chronic medical condition
Hirschsprung Disease in Children
- What is Hirschsprung disease?
Answer: A congenital disorder characterized by the absence of ganglion cells in the distal colon - What is the primary cause of Hirschsprung disease?
Answer: Failure of neural crest cells to migrate during fetal development - At what age is Hirschsprung disease typically diagnosed?
Answer: Often in the neonatal period or early infancy - What is the most common presenting symptom of Hirschsprung disease in neonates?
Answer: Delayed passage of meconium (>24-48 hours after birth) - Which gender is more commonly affected by Hirschsprung disease?
Answer: Males (4:1 male to female ratio) - What percentage of the colon is most commonly affected in Hirschsprung disease?
Answer: The rectosigmoid colon (75-80% of cases) - What is the gold standard diagnostic test for Hirschsprung disease?
Answer: Rectal biopsy showing absence of ganglion cells - Which imaging study is often used in the initial evaluation of Hirschsprung disease?
Answer: Contrast enema - What is the characteristic finding on contrast enema in Hirschsprung disease?
Answer: Transition zone between narrowed aganglionic segment and dilated normal bowel - Which genetic syndrome is associated with an increased risk of Hirschsprung disease?
Answer: Down syndrome - What is the role of anorectal manometry in diagnosing Hirschsprung disease?
Answer: It can demonstrate absence of the rectoanal inhibitory reflex - What is the standard surgical treatment for Hirschsprung disease?
Answer: Pull-through procedure (e.g., Swenson, Duhamel, or Soave procedure) - What is enterocolitis in the context of Hirschsprung disease?
Answer: A potentially life-threatening complication characterized by inflammation of the bowel - Which neurotransmitter is absent in the aganglionic segment of Hirschsprung disease?
Answer: Nitric oxide - What is total colonic aganglionosis?
Answer: A severe form of Hirschsprung disease affecting the entire colon and potentially part of the small intestine - Which gene is most commonly associated with Hirschsprung disease?
Answer: RET gene - What is the role of rectal irrigation in managing Hirschsprung disease?
Answer: It can help prevent constipation and enterocolitis before definitive surgery - What is the long-term prognosis for children with Hirschsprung disease after surgical correction?
Answer: Generally good, with most achieving normal bowel function - What is the significance of calretinin staining in diagnosing Hirschsprung disease?
Answer: Absence of calretinin-positive nerve fibers supports the diagnosis - What is the role of laparoscopy in the surgical management of Hirschsprung disease?
Answer: It can be used for minimally invasive pull-through procedures - What is the typical age for definitive surgical correction of Hirschsprung disease?
Answer: Between 3-6 months of age, if diagnosed early - What is the significance of acetylcholinesterase staining in diagnosing Hirschsprung disease?
Answer: Increased staining in the aganglionic segment supports the diagnosis - What is the role of genetic testing in Hirschsprung disease?
Answer: It can confirm the diagnosis and help with genetic counseling - What is the ultra-short segment Hirschsprung disease?
Answer: Aganglionosis limited to the anal canal and distal rectum - What is the significance of transition zone pull-through in Hirschsprung disease surgery?
Answer: It can lead to persistent obstructive symptoms and should be avoided - What is the role of botulinum toxin injection in managing Hirschsprung disease?
Answer: It can be used to treat internal sphincter achalasia post-surgery - What is the significance of HAEC (Hirschsprung-associated enterocolitis) score?
Answer: It helps assess the severity of enterocolitis in Hirschsprung disease - What is the role of probiotics in managing Hirschsprung disease?
Answer: They may help reduce the risk of Hirschsprung-associated enterocolitis
