Intestinal Atresia and Stenosis
Definitions
- Atresia — complete luminal interruption (no passage of intestinal contents)
- Stenosis — partial narrowing of the lumen producing varying degrees of obstruction
Epidemiology and Incidence
- Overall incidence: ≈ 1 in 1,500 live births (varies by series and lesion): intestinal atresia/stenosis account for ≈ 30% of congenital intestinal obstructions.
- Distribution: jejunoileal atresias are most common (approximately half of cases), duodenal next, colon least common.
- Multiple atresias occur in roughly 10%–20% of cases (higher in jejunoileal and colonic disease).
Anatomic Sites and Relative Frequency
| Site | Relative frequency / key points |
|---|---|
| Jejunum / ileum | Most common site overall (~50% of intestinal atresias); often due to intrauterine vascular events; multiple lesions possible. |
| Duodenum | Second most common; frequently associated with other congenital anomalies (Down syndrome, cardiac defects, annular pancreas); often due to failed recanalization. |
| Colon | Least common (~10% of intestinal atresia); ascending colon most frequently affected; often associated with other intestinal atresias or Hirschsprung disease. |
Pathogenesis
Duodenal atresia / stenosis
- Primary mechanism: failure of recanalization of the duodenal lumen during embryogenesis (around 8th–10th gestational week).
- Explains frequent association with other developmental anomalies and syndromes.
Jejunoileal and colonic atresia / stenosis
- Most commonly due to intrauterine vascular accidents (ischemic necrosis) in the 2nd–3rd trimester leading to resorption of affected segment and resultant blind ends, mesenteric defects, or fibrous cords.
- Contributing mechanisms: volvulus, intussusception, incarcerated omphalocele/gastroschisis, focal peritonitis, or extrinsic compression.
- Apple-peel (type IIIb) deformity reflects extensive mesenteric vascular loss with distal small-bowel supplied by a single vessel.
Clinical Presentation — Key Neonatal Features
- Classic features suggestive of neonatal intestinal obstruction: bilious vomiting, progressive abdominal distension, failure to pass meconium.
- Timing: proximal obstructions (duodenal) present early—often within first 24 hours; distal obstructions may present later (24–72+ hours) with progressive distension.
- Complete obstruction → early and persistent vomiting; partial obstruction/stenosis → intermittent vomiting, poor feeding, failure to thrive.
Duodenal Atresia and Stenosis — Focused Review
- Incidence: ~1 in 5,000–10,000 live births; accounts for ~1/3 of intestinal atresias.
- Associations: strong link with trisomy 21 (≈30% of cases), other chromosomal abnormalities, annular pancreas (~20%–30%), cardiac defects, malrotation, VACTERL features.
- Presentation: bilious vomiting on day 1 of life is classic; epigastric distension; dehydration, electrolyte disturbances, metabolic alkalosis possible.
- Types (anatomic):
- Type I (membranous/web): thin mucosal diaphragm (often fenestrated; «windsock» if distal ballooning).
- Type II: fibrous cord connecting blind ends (rare in duodenum context).
- Type III: discontinuous blind ends with gap.
- Stenosis: incomplete lumen formation causing narrowing.
Diagnosis — Duodenal
- Prenatal: ultrasound may show polyhydramnios and the sonographic double-bubble sign; fetal MRI may better define contents and associated anomalies.
- Postnatal: orogastric aspiration (large volumes >20 mL suggest obstruction), plain radiograph showing classic double-bubble (gas in stomach and proximal duodenum with distal gas absent in complete obstruction).
- Upper GI contrast study: used to exclude malrotation with midgut volvulus and to define level and nature of obstruction.
- Genetic testing: karyotype or microarray recommended due to high chromosomal association.
Management — Duodenal
- Initial stabilization: NPO, nasogastric decompression, IV fluids, correct electrolytes, temperature control, broad-spectrum antibiotics per local protocols if perforation or contamination suspected.
- Definitive surgical options:
- Duodenoduodenostomy (diamond or side-to-side): procedure of choice for most duodenal atresias and stenoses.
- Duodenojejunostomy: alternative when duodenoduodenostomy not feasible; higher theoretical risk of blind loop problems.
- Web excision via duodenotomy for Type I webs; windsock lesions may need web resection and duodenoplasty.
- Tapering enteroplasty may be used if proximal dilation is severe.
- Perioperative issues: consider associated cardiac anomalies and prematurity when planning timing and anesthesia.
Prognosis — Duodenal
- Isolated duodenal atresia: low operative mortality (<5%) in modern practice; worse outcomes with major cardiac anomalies, prematurity, or chromosomal disorders.
- Long-term: gastroesophageal reflux, delayed gastric emptying/gastroparesis, peptic ulceration, recurrent obstruction from adhesions, and rarely biliary complications or megaduodenum when combined with annular pancreas.
Jejunoileal Atresia (J-IA) — Focused Review
- Incidence: approximately 1 in 1,500 live births (varies); accounts for ~50% of intestinal atresias.
- Etiology: predominantly intrauterine mesenteric vascular accidents; associations include gastroschisis, omphalocele, intrauterine volvulus, meconium ileus.
- Multiple atresias occur in ~10%–20% of cases and increase risk of short-bowel syndrome after resection.
Classification (Louw / Grosfeld modification)
- Type I — mucosal web / membrane: bowel and mesentery intact; serosa continuous.
- Type II — blind ends connected by fibrous cord; mesentery intact.
- Type IIIa — blind ends with a mesenteric gap defect (V-shaped mesenteric defect).
- Type IIIb — "apple‑peel" or "Christmas tree" deformity: proximal jejunal atresia with large mesenteric defect and distal bowel coiled around a single vascular pedicle.
- Type IV — multiple atresias ("string of sausages").
Clinical features — J-IA
- Maternal polyhydramnios in ~25%–50% of cases when obstruction is proximal or extensive.
- Neonate: bilious vomiting and variable abdominal distension; proximal jejunal atresia → scaphoid abdomen and early vomiting; distal ileal atresia → progressive distension and delayed presentation.
- Failure to pass meconium occurs in ~50%–60%.
Diagnosis — J-IA
- Plain abdominal radiograph: multiple dilated bowel loops with air-fluid levels; absence of distal gas in complete obstruction.
- Contrast enema: useful to evaluate distal colon (microcolon suggests unused colon secondary to proximal obstruction) and to differentiate from meconium ileus or Hirschsprung disease.
- Upper GI contrast studies are not routinely required but can evaluate for malrotation or proximal volvulus.
- Prenatal ultrasound: multiple dilated bowel loops, polyhydramnios in some cases.
Management — J-IA
- Stabilization: NPO, NG decompression, IV fluids, correct electrolytes, broad-spectrum antibiotics if indicated.
- Surgery:
- Resection of atretic segment with primary end-to-end anastomosis is standard when feasible.
- Tapering enteroplasty for massively dilated proximal bowel to improve size match and function.
- Temporary enterostomy (stoma) may be used when there is marked size discrepancy, contamination, or instability; delayed anastomosis planned.
- Type IIIb and multiple (Type IV) lesions carry higher risk for short-bowel and may require staged procedures and long-term intestinal rehabilitation.
- Postoperative care: parenteral nutrition often required until enteral feeding tolerated; monitor for sepsis, anastomotic leak, adhesive obstruction.
Prognosis — J-IA
- Overall good when adequate bowel preserved; survival improved with modern neonatal intensive care.
- Worse prognosis with apple‑peel (IIIb) and multiple atresias (IV) due to risk of short-bowel syndrome and dependence on long-term parenteral nutrition.
- Long-term complications: adhesive small-bowel obstruction, anastomotic strictures, short-bowel sequelae including malabsorption and B12 deficiency after distal ileal resection.
Colonic Atresia
- Incidence: rare (estimates vary widely; approximately 1 in 10,000–66,000 live births); represents ~5%–10% of intestinal atresias.
- Most frequent site: ascending colon; significant proportion have additional intestinal atresias or Hirschsprung disease.
- Presentation: delayed meconium passage, abdominal distension, vomiting—often presents after 2nd day of life for distal lesions.
- Diagnosis: abdominal radiographs and contrast enema demonstrating microcolon and level of obstruction.
- Management: surgical resection and primary anastomosis when feasible; staged ostomy may be used. Evaluate for associated Hirschsprung disease before definitive repair.
- Prognosis: generally good with prompt diagnosis and treatment; depends on associated anomalies.
Diagnostic Algorithm — Practical Approach
- Suspect intestinal atresia/stenosis in neonate with bilious vomiting, abdominal distension, or failure to pass meconium.
- Immediate actions: NPO, NG tube, IV access, fluid resuscitation, electrolyte correction, temperature control; call pediatric surgery.
- Obtain plain abdominal radiograph.
- Interpret radiograph:
- Double‑bubble with absence of distal gas → duodenal atresia (confirm with upper GI to exclude malrotation/volvulus).
- Multiple dilated loops & air-fluid levels → jejunoileal obstruction; consider contrast enema to evaluate distal colon.
- Distal gas/transition on contrast enema → localize colonic atresia vs other causes.
- Prenatal findings of polyhydramnios and dilated bowel loops should prompt tertiary perinatal planning and family counseling.
Perioperative and Long-term Management Considerations
- Monitor and manage fluid, electrolyte, temperature, and acid–base status preoperatively.
- Provide parenteral nutrition when prolonged ileus or extensive resection anticipated; central venous access and TPN monitoring are essential.
- Minimize bowel resection when feasible; consider bowel-sparing procedures (mucosal tapering, Bianchi or STEP procedures in select salvage cases of short bowel) in specialized centers.
- Multidisciplinary care: neonatology, pediatric surgery, nutrition, gastroenterology, genetics, and social work for family counseling and long-term follow-up.
- Growth, developmental surveillance, and screening for micronutrient deficiencies (iron, vitamins, B12) after ileal resection.
Complications — Immediate and Long-term
- Immediate: sepsis, anastomotic leak, perforation, abdominal compartment syndrome, short bowel physiology after extensive resection.
- Short-term: prolonged ileus, feeding intolerance, cholestasis from prolonged TPN, central line–associated bloodstream infections.
- Long-term: adhesive small-bowel obstruction, strictures, chronic malabsorption, growth failure, neurodevelopmental delay related to prematurity or prolonged illness, B12 deficiency after ileal resection.
Summary Table — High-yield Differences
| Feature | Duodenal Atresia/Stenosis | Jejunoileal Atresia | Colonic Atresia |
|---|---|---|---|
| Typical presentation timing | First day of life; bilious emesis; double bubble | Early but may present over 1–3 days; bilious vomiting, distension | Often after day 2; distension, failure to pass meconium |
| Pathogenesis | Failed recanalization | Intrauterine vascular accident (ischemia) | Vascular accident or in utero mesenteric event |
| Associations | Trisomy 21, cardiac defects, annular pancreas | Gastroschisis, omphalocele, volvulus, meconium ileus; cystic fibrosis reported | Hirschsprung disease; other atresias |
| Radiograph | Double bubble, no distal gas | Multiple dilated loops, air-fluid levels, absent distal gas | Dilated proximal loops; contrast enema shows microcolon |
| First-line definitive surgery | Duodenoduodenostomy (preferred) | Resection + primary anastomosis; tapering enteroplasty if needed | Resection + anastomosis or staged ostomy depending on stability |
| Key board pearl | High association with Down syndrome and cardiac defects; think ‘double bubble’ | Think vascular accident; classification types I–IV, apple-peel type IIIb = poor prognosis | Rare; always consider Hirschsprung and other intestinal atresias |
Clinical Pearls
- Bilious vomiting in a neonate is emergent until proven otherwise — immediate decompression and surgical consultation required.
- Double-bubble sign does not automatically equal duodenal atresia; malrotation with midgut volvulus must be excluded before surgery.
- Apple-peel (type IIIb) jejunoileal atresia is associated with extensive mesenteric loss and higher risk of short-bowel syndrome — anticipate complex postoperative nutrition needs.
- Obtain karyotype/microarray and fetal echocardiography for prenatal or postnatal duodenal atresia due to strong chromosomal and cardiac associations.
- When multiple atresias are present, plan surgeries to minimize cumulative bowel loss and coordinate with intestinal rehabilitation teams if short bowel is likely.