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Emergency And Acute Medicine – Hirschsprung Disease
Basics
Condition Overview
First described in 1886 by Harold Hirschsprung as a cause of severe constipation in early infancy. Hirschsprung disease is a congenital aganglionic megacolon occurring in approximately 1:5,000 live births. Mortality associated with Hirschsprung-related enterocolitis remains high at 35–50%.
Etiology And Pathogenesis
The disease is caused by absence of enteric ganglion cells in the distal bowel. Normally, neural crest cells migrate along the gastrointestinal tract, reaching the proximal colon by 8 weeks of gestation and the rectum by 12 weeks. Failure of migration into the parasympathetic Meissner (submucosal) and Auerbach (myenteric) plexuses results in an aganglionic segment and clinical disease.
The affected bowel typically begins at the internal anal sphincter and involves the rectosigmoid colon in about 75% of cases, though it may extend proximally and, in rare cases, involve the entire GI tract, which is often fatal. The aganglionic segment remains chronically contracted, producing functional obstruction, while proximal bowel dilates to accommodate retained stool. Anal stimulation may temporarily allow stool passage.
Genetic associations include mutations of the RET proto-oncogene in both familial and sporadic forms. The male-to-female ratio is approximately 4:1. About 8% have a positive family history, with 5–12% of siblings affected. Chromosomal abnormalities occur in 5–15%, most commonly trisomy 21 (Down syndrome). Other congenital anomalies are present in approximately 18%, including gastrointestinal, cardiac, craniofacial abnormalities, cleft palate, and congenital deafness.
Diagnosis
Clinical Features
Most patients are diagnosed by 2 years of age, with presentation varying by age.
Neonatal presentation
Abdominal distension, failure to pass meconium within the first 48 hours of life, vomiting, enterocolitis characterized by abdominal pain, fever, foul-smelling and/or bloody diarrhea, vomiting progressing to sepsis and possible intestinal perforation, and sepsis.
Infancy
Chronic constipation, progressive abdominal distension, vomiting, failure to thrive, enterocolitis, and possible toxic megacolon.
Later childhood And Adulthood
Chronic constipation with obstruction, often refractory to standard treatment, rare overflow incontinence, abdominal distension, bloody foul-smelling diarrhea, malnutrition, and episodes of enterocolitis with systemic toxicity.
History
Frequent need for rectal stimulation or enemas to achieve bowel movements, narrow-caliber stools, encopresis and diarrhea are uncommon, and absence of typical triggers for functional constipation such as fissures, toilet training issues, or dietary factors.
Physical Examination
Possible palpable colon on the left, abdominal distension with signs of obstruction, findings consistent with malnutrition or failure to thrive, and an empty rectal vault on digital rectal examination.
Initial Evaluation
Plain abdominal radiographs commonly show distended small bowel and proximal colon (megacolon) with an empty rectum and a transition zone into a narrowed rectosigmoid segment. Neonates often demonstrate a distal obstructive pattern. In chronic constipation, imaging may show only fecal loading. In enterocolitis, bowel wall edema or pneumatosis intestinalis may be present.
Diagnostic Studies And Interpretation
Laboratory Studies
CBC, electrolytes, glucose, BUN, creatinine, urinalysis, and blood cultures if the patient appears toxic.
Imaging
Barium enema should be obtained after stabilization and is contraindicated if perforation or severe enterocolitis is suspected. Findings include a dilated proximal colon with a narrowed aganglionic distal segment, uncoordinated peristalsis, and a transition zone. A nondistensible rectum and delayed barium evacuation are classic findings. The transition zone may be absent in neonates or in infants who have undergone repeated rectal exams or enemas.
Procedures And Surgical Diagnosis
Rectal manometry may assist in diagnosis but is often abnormal in long-standing constipation; affected patients fail to demonstrate reflex relaxation of the internal anal sphincter with rectal balloon inflation. Definitive diagnosis requires a full-thickness rectal biopsy demonstrating absence of ganglion cells, which remains the diagnostic gold standard.
Differential Diagnosis
Neonates
Meconium ileus or meconium plug syndrome associated with cystic fibrosis, intestinal or anal atresia or hypoplasia, malrotation or duplication with volvulus, necrotizing enterocolitis, and sepsis.
Infants And Children
Functional constipation, toxic etiologies such as opiates or anticholinergics, infectious causes including botulism, acquired aganglionic colon, metabolic or endocrine disorders such as hypothyroidism, parathyroid or adrenal disease, electrolyte abnormalities, spinal cord defects, and abdominal masses.
Treatment
Initial Stabilization And Support
Airway, breathing, and circulation management with appropriate monitoring. Administer isotonic IV fluid bolus (20 mL/kg) for dehydration, shock, or sepsis.
Emergency Department Management
Infants should be treated as having bowel obstruction; nasogastric decompression is indicated if vomiting is present. Early consultation with a pediatric surgeon is essential. Broad-spectrum triple antibiotics are indicated for toxic patients or those with enterocolitis. Unstable patients may require emergent decompression with a loop colostomy. Stable patients may complete diagnostic evaluation as outpatients.
Definitive treatment consists of surgical resection of the aganglionic bowel with pull-through of normally innervated bowel to within 1 cm of the anal opening. Enterocolitis may occur before or after surgical intervention.
Medications
Ampicillin 50 mg/kg IV divided every 6 hours.
Gentamicin 2.5 mg/kg IV divided every 12–24 hours.
Metronidazole 7.5 mg/kg IV divided every 12–48 hours.
Follow-Up And Disposition
Admission Criteria
Neonates and infants with bowel obstruction, any patient with enterocolitis, and ill-appearing infants requiring NICU or PICU care with pediatric surgical support.
Discharge Criteria
Well-hydrated patients tolerating oral intake, typically older children presenting primarily with constipation, with reliable caregivers and close outpatient follow-up arranged.
Referral Considerations
Ongoing care should be coordinated with pediatric gastroenterology and pediatric surgery.
Key Clinical Insights And Common Pitfalls
Clinical presentation varies widely with age, ranging from neonatal obstruction to chronic constipation. The disease exists on a spectrum from mild constipation to life-threatening enterocolitis. Toxic patients require immediate stabilization, antibiotics, urgent imaging, and surgical consultation. Failure to recognize enterocolitis can result in rapid deterioration and death.
Basics
Condition Overview
First described in 1886 by Harold Hirschsprung as a cause of severe constipation in early infancy. Hirschsprung disease is a congenital aganglionic megacolon occurring in approximately 1:5,000 live births. Mortality associated with Hirschsprung-related enterocolitis remains high at 35–50%.
Etiology And Pathogenesis
The disease is caused by absence of enteric ganglion cells in the distal bowel. Normally, neural crest cells migrate along the gastrointestinal tract, reaching the proximal colon by 8 weeks of gestation and the rectum by 12 weeks. Failure of migration into the parasympathetic Meissner (submucosal) and Auerbach (myenteric) plexuses results in an aganglionic segment and clinical disease.
The affected bowel typically begins at the internal anal sphincter and involves the rectosigmoid colon in about 75% of cases, though it may extend proximally and, in rare cases, involve the entire GI tract, which is often fatal. The aganglionic segment remains chronically contracted, producing functional obstruction, while proximal bowel dilates to accommodate retained stool. Anal stimulation may temporarily allow stool passage.
Genetic associations include mutations of the RET proto-oncogene in both familial and sporadic forms. The male-to-female ratio is approximately 4:1. About 8% have a positive family history, with 5–12% of siblings affected. Chromosomal abnormalities occur in 5–15%, most commonly trisomy 21 (Down syndrome). Other congenital anomalies are present in approximately 18%, including gastrointestinal, cardiac, craniofacial abnormalities, cleft palate, and congenital deafness.
Diagnosis
Clinical Features
Most patients are diagnosed by 2 years of age, with presentation varying by age.
Neonatal presentation
Abdominal distension, failure to pass meconium within the first 48 hours of life, vomiting, enterocolitis characterized by abdominal pain, fever, foul-smelling and/or bloody diarrhea, vomiting progressing to sepsis and possible intestinal perforation, and sepsis.
Infancy
Chronic constipation, progressive abdominal distension, vomiting, failure to thrive, enterocolitis, and possible toxic megacolon.
Later childhood And Adulthood
Chronic constipation with obstruction, often refractory to standard treatment, rare overflow incontinence, abdominal distension, bloody foul-smelling diarrhea, malnutrition, and episodes of enterocolitis with systemic toxicity.
History
Frequent need for rectal stimulation or enemas to achieve bowel movements, narrow-caliber stools, encopresis and diarrhea are uncommon, and absence of typical triggers for functional constipation such as fissures, toilet training issues, or dietary factors.
Physical Examination
Possible palpable colon on the left, abdominal distension with signs of obstruction, findings consistent with malnutrition or failure to thrive, and an empty rectal vault on digital rectal examination.
Initial Evaluation
Plain abdominal radiographs commonly show distended small bowel and proximal colon (megacolon) with an empty rectum and a transition zone into a narrowed rectosigmoid segment. Neonates often demonstrate a distal obstructive pattern. In chronic constipation, imaging may show only fecal loading. In enterocolitis, bowel wall edema or pneumatosis intestinalis may be present.
Diagnostic Studies And Interpretation
Laboratory Studies
CBC, electrolytes, glucose, BUN, creatinine, urinalysis, and blood cultures if the patient appears toxic.
Imaging
Barium enema should be obtained after stabilization and is contraindicated if perforation or severe enterocolitis is suspected. Findings include a dilated proximal colon with a narrowed aganglionic distal segment, uncoordinated peristalsis, and a transition zone. A nondistensible rectum and delayed barium evacuation are classic findings. The transition zone may be absent in neonates or in infants who have undergone repeated rectal exams or enemas.
Procedures And Surgical Diagnosis
Rectal manometry may assist in diagnosis but is often abnormal in long-standing constipation; affected patients fail to demonstrate reflex relaxation of the internal anal sphincter with rectal balloon inflation. Definitive diagnosis requires a full-thickness rectal biopsy demonstrating absence of ganglion cells, which remains the diagnostic gold standard.
Differential Diagnosis
Neonates
Meconium ileus or meconium plug syndrome associated with cystic fibrosis, intestinal or anal atresia or hypoplasia, malrotation or duplication with volvulus, necrotizing enterocolitis, and sepsis.
Infants And Children
Functional constipation, toxic etiologies such as opiates or anticholinergics, infectious causes including botulism, acquired aganglionic colon, metabolic or endocrine disorders such as hypothyroidism, parathyroid or adrenal disease, electrolyte abnormalities, spinal cord defects, and abdominal masses.
Treatment
Initial Stabilization And Support
Airway, breathing, and circulation management with appropriate monitoring. Administer isotonic IV fluid bolus (20 mL/kg) for dehydration, shock, or sepsis.
Emergency Department Management
Infants should be treated as having bowel obstruction; nasogastric decompression is indicated if vomiting is present. Early consultation with a pediatric surgeon is essential. Broad-spectrum triple antibiotics are indicated for toxic patients or those with enterocolitis. Unstable patients may require emergent decompression with a loop colostomy. Stable patients may complete diagnostic evaluation as outpatients.
Definitive treatment consists of surgical resection of the aganglionic bowel with pull-through of normally innervated bowel to within 1 cm of the anal opening. Enterocolitis may occur before or after surgical intervention.
Medications
Ampicillin 50 mg/kg IV divided every 6 hours.
Gentamicin 2.5 mg/kg IV divided every 12–24 hours.
Metronidazole 7.5 mg/kg IV divided every 12–48 hours.
Follow-Up And Disposition
Admission Criteria
Neonates and infants with bowel obstruction, any patient with enterocolitis, and ill-appearing infants requiring NICU or PICU care with pediatric surgical support.
Discharge Criteria
Well-hydrated patients tolerating oral intake, typically older children presenting primarily with constipation, with reliable caregivers and close outpatient follow-up arranged.
Referral Considerations
Ongoing care should be coordinated with pediatric gastroenterology and pediatric surgery.
Key Clinical Insights And Common Pitfalls
Clinical presentation varies widely with age, ranging from neonatal obstruction to chronic constipation. The disease exists on a spectrum from mild constipation to life-threatening enterocolitis. Toxic patients require immediate stabilization, antibiotics, urgent imaging, and surgical consultation. Failure to recognize enterocolitis can result in rapid deterioration and death.
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