Meconium Ileus
Pathology
Obstruction of small bowel at terminal ilues with inspissated meconium
- Simple MI (60%): no GI complications
- Complicated (40%): perforation, meconium peritonitis, atresia, volvulus
If not picked up antenatally usually present in first 3 days
Abdominal distention
Failure to pass meconium
+/- Vomiting
10% of CF present at MI (usually severe genotypes)
~90% of infants with MI have CF
Ix
Antenatal US can pick up small bowel obstruction
AXR
- gas filled dilated loops of small bowel
- perforation (pneumoperitoneum)
- calcifications (in-utero perforation and peritonitis)
IF AXR shows no perforation
Contrast enema (gastrografin is hyperosmotic, breaks down plug)
- microcolon of disuse
- meconium pellets in the distal ileum
Sweat test for CF
- after 48 hours if >2.5kg, stable, in cot (not warmer)
- otherwise mutation analysis (NBS often neg for unknown reasons)
Rx
NG decompression
Simple MI: Hyperosmolar gastrograffin enema
- ⅓ success
- 5% risk of perforation/fluid shifts/shock
Complex or failed simple: operative
- enterotomy and levage
- enterostomy
- resection of dilated/perforated/atretic bowel
Na replacement
- CF + ileostomy = high risk of total body Na depletion in face of normal serum Na = poor weight gain