MECONIUM ILEUS

Meconium ileus is a neonatal intraluminal intestinal obstruction caused by inspissated meconium
blocking the distal ileum. Occurs in 10-15% of all patients with cystic fibrosis, and 85-95% of patients with meconium ileus have cystic fibrosis. The meconium has a reduced water, abnormal high protein and
mucoprotein content, the result of decreased pancreatic enzyme activity and prolonged small bowel intestinal transit time.
Meconium Ileus is classified into two types:
(1) Simple meconium ileus: The distal small bowel (10-30
cm of distal ileum) is relatively small, measuring less than 2 cm in diameter and contains concretions of gray, inspissated meconium with the consistency of thick glue or putty. It is often beaklike in appearance, conforming to the shape of the contained pellets. Proximally, the mid-ileum is large, measuring up to 7 cm in diameter. It is greatly distended by a mass of extremely thick, tenacious, dark green or tarry meconium. The unused small colon (microcolon) contains a small amount of inspissated mucus or grayish meconium.
(2) Complicated meconium ileus: usually occurs during the prenatal period associated to volvulus, atresias, gangrene, perforation or peritonitis. A cystic mass or atresia of the bowel may occur.

The degree of obstruction varies, may be cured in mild cases by rectal irrigations. Failure to pass
meconium, abdominal distension and vomiting are seen in more severe cases. The diagnosis is suspected with findings of: multiple loops of dilated small bowel and coarse granular "soap-bubble" appearance on plain abdominal films. Some cases may show calcifications in the peritoneum (Meconium peritonitis). The Sweat Test is diagnostic of cystic fibrosis (value over 60 meq/L of sweat sodium or chloride are diagnostic). This test is not useful in infant during first weeks of life.

Therapy is either:
(1) Nonoperative- should be tried first. It consist of a careful gastrografin enema after
the baby is well-hydrated. Gastrografin is a hyperosmolar aqueous solution of meglumine diatrizoate containing 0.1% polysorbate-80 (tween-80, a wetting agent) and 37% iodine. Its success is due to the high osmolarity (1700 mOsm/liter) which draws fluid into the bowel and softens and loosens the meconium.
(2) Surgical therapy that has included: ileostomy with irrigation, resection with anastomosis, and resection with ileostomy (Mikulicz, Bishop-Kopp, and Santulli). Post-operative management includes: 10% acetylcysteine p.o., oral feedings (Pregestimil), pancreatic enzyme replacement, and prophylactic pulmonary therapy. Long-term prognosis depends on the degree of severity and progression of cystic fibrosis pulmonary disease.