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Meconium ileus, meconium plug and spontaneous intestinal perforation
Meconium ileus is obstruction of the terminal ileum by thick, sticky meconium, and it is almost always the first sign of cystic fibrosis; an uncomplicated case is treated with a hyperosmolar contrast enema and a complicated one with surgery.
Why it matters in the exam
The exam shows a newborn with a distended abdomen, green vomiting and no passage of meconium. The X-ray shows dilated loops, sometimes few fluid levels (thick meconium does not form levels) and a "soap bubble" appearance in the right lower abdomen. A contrast enema shows a microcolon (a narrow, unused colon) and meconium pellets in the terminal ileum. The meconium in meconium ileus is low in water and rich in proteins (such as albumin), which makes it especially sticky. About 10% to 20% of newborns with cystic fibrosis present with meconium ileus, so every such newborn needs a sweat test and genetic testing.
"Simple" meconium ileus is treated with a Gastrografin enema (a water-soluble, hyperosmolar contrast agent) under fluoroscopy, which draws water into the bowel lumen and loosens the pellets; intravenous fluids must be given at the same time because the enema causes fluid loss. The enema succeeds in about half of cases and can be repeated. "Complicated" meconium ileus — volvulus, atresia, perforation, a meconium pseudocyst or peritonitis with calcification — needs surgery: enterotomy and irrigation (sometimes with N-acetylcysteine), resection and a stoma as needed.
Meconium plug (and "small left colon syndrome") is often seen in newborns of diabetic mothers: the contrast enema is both diagnosis and treatment, but Hirschsprung disease and cystic fibrosis should be considered. Spontaneous intestinal perforation (SIP) occurs in very-low-birth-weight preterm infants in the first days of life, linked with indomethacin or steroids; it is a single perforation in the terminal ileum, without pneumatosis and without extensive necrosis, with a bluish abdomen and free air. Treatment — a peritoneal drain or surgery, and the prognosis is better than in NEC.
Key points
- Meconium ileus — almost always cystic fibrosis.
- Soap bubbles and a microcolon.
- Simple — Gastrografin enema with fluids; complicated — surgery.
- Meconium plug — infant of a diabetic mother; exclude Hirschsprung disease.
- SIP — small preterm, first days, no pneumatosis.
Summary table
| Condition | Clues | Test | Treatment |
|---|---|---|---|
| Simple meconium ileus | Distended abdomen, soap bubbles, microcolon | Contrast enema | Gastrografin enema with intravenous fluids |
| Complicated meconium ileus | Calcification, mass, signs of peritonitis | X-ray and ultrasound | Surgery: irrigation, resection, stoma |
| Meconium plug | Infant of a diabetic mother, narrow left colon | Contrast enema | The enema treats it; exclude Hirschsprung and cystic fibrosis |
| SIP | Very small preterm, first days, indomethacin or steroids | Free air without pneumatosis | Peritoneal drain or surgery |
| NEC (for comparison) | Preterm after feeds start, bloody stool | Pneumatosis, portal venous gas | Nil by mouth, antibiotics, surgery for necrosis |
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Sources
- Holcomb and Ashcraft's Pediatric Surgery, 7th edition (2019) — Meconium Disease
- Cystic Fibrosis Foundation consensus guidelines for diagnosis of cystic fibrosis, 2017 — Newborn screening and sweat chloride
Sources are given for further reading; the text is written afresh and not copied from them.
Reviewed by the Examqo AI Professor · 2026-11-06. The text may contain errors; when in doubt, check the source.