Meconium ileus

Gastrointestinal involvement may present initially as small bowel obstruction shortly after birth (known as meconium ileus) due to abnormally thick meconium that cannot be passed. Older CF patients may develop distal intestinal obstruction syndrome (DIOS), formerly called meconium ileus equivalent, which occurs due to fecal impaction in the terminal ileum and cecum. 

Other complications may include gastroesophageal reflux, dysmotility, intussusception, volvulus, atresia, rectal prolapse, and complications related to corrective surgery for meconium ileus.6... 

Intestinal obstruction may be manifested as meconium ileus, distal intestinal obstruction syndrome, or intussusception on abdominal x-ray or computed tomography scan. Rectal prolapse may be noted on physical exam. 

Treatment of distal intestinal obstruction syndrome (DIOS) consists of oral or nasogastric administration of polyethylene glycol electrolyte (PEG) solutions. Enemas may also be used to facilitate stool clearance. IV fluids are often required to correct dehydration due to vomiting or decreased oral intake. Re-evaluation of enzyme compliance and dosing is essential to prevent further episodes. Patients with recurrent symptoms may require daily PEG administration (Miralax ).5 Severe presentations of DIOS or initial meconium ileus may require surgical resection. 

Meconium is the earliest stool of an infant, composed of materials ingested during the time the infant spends in the uterus. It should be completely passed by the end of the first few days of postpartum life, with the stools progressing toward yellow (digested milk). Sometimes the meconium becomes thickened and congested in the ileum, a condition known as meconium ileus. Meconium ileus is often the first symptom of CF. In CF patients, the meconium can form a bituminous black-green mechanical obstruction in a segment of the ileum. About 20% of cases of CF present with meconium ileus. 

History of recurrent bowel obstruction, meconium ileus, Crohn s disease, short bowel syndrome or prior intestinal surgery... 

Amidotrizoate enemas are still sometimes used to treat meconium ileus or constipation, and it is important to give intravenous fluids so as to avoid dehydration. Hypomagnesemia can also occur (150). Osmotic effects lower in the gastrointestinal tract have even led to distention and cecal perforation (151). Stasis of amidotrizoate in dilated loops of bowel can cause inflammatory changes or necrosis (152,153). 

Godson C, Ryan MP, Brady HR, Bourke S, FitzGerald MX. Acute hypomagnesaemia complicating the treatment of meconium ileus equivalent in cystic fibrosis. Scand J Gastroenterol Suppl 1988 143 148-50. 

Leonidas JC, Burry VF, Fellows RA, Beatty EC. Possible adverse effect of methylglucamine diatrizoate compounds on the bowel of newborn infants with meconium ileus. Radiology 1976 121(3 Pt l) 693-6. 

Zielenski J, Corey M, Rozmahel R, Markiewicz D, Aznarez I, Casals T, et al. Detection of cystic fibrosis modifier locus for meconium ileus on human chromosome 19ql3. Nat Genet 1999 22 128-9. 

The clinical abnormalities related to the gastrointestinal tract are not life-threatening and can be treated. In newborns with CF, intestinal obstruction (meconium ileus) can occur in 10-20% of cases due to failure of digestion of intraluminal contents due to lack of pancreatic enzymes in utero. Exocrine pancreatic enzyme deficiency is present from birth affecting both lipid and protein digestion. In general, carbohydrate digestion is not severely impaired. 

Treating Meconium Ileus and Distal Intestinal Obstruction Syndrome... 

The treatment of meconium ileus or distal intestinal obstruction syndrome sometimes can be limited to the use of enemas with iso-osmolar... 

Adverse effects including blurred vision, exacerbation of glaucoma due to mydriasis and cycloplegia, dry mouth, respiratory depression, nausea, constipation, fetal meconium ileus, paralytic ileus, impairment of renal blood flow with azotemia, and urinary retention frequently complicate therapy with trimethaphan camsylate. Because of the frequency and severity of the side effects associated with this drug and the availability of more effective agents, it is now rarely used. 

It also has been used with some success for the management of bowel obstruction due to meconium ileus, which is associated with newborn children with cystic fibrosis. 

For practical purposes, the differential diagnosis of low intestinal obstruction in the neonate consists of five conditions. Two conditions involve the distal ileum and include ileal atresia and meconium ileus, and three involve the colon, which are colonic atresia, Hirschsprung s disease, and functional immaturity of the colon that includes meconium plug... 

Fig. 1.20a,b. Meconium ileus, a Supine plain radiograph shows marked bowel distension with suggestive evidence of mottled air and feces in ascending colon and terminal ileum, b Upright film shows absence of well-defined air-fiuid levels... 

Fig. 1.22a,b. Meconium ileus, a Water-soluble contrast enema showing a microcolon with scattered filling defects that correspond to inspissated meconium, b The enema was continued with reflux of the contrast medium into the terminal ileum, showing Ailing defects that represent meconium pellets. The patient was discharged within 48 h of successful treatment... 

Meconium ileus maybe complicated by volvulus of a distal intestinal loop, perforation, or atresia. All patients with complicated meconium ileus require surgical intervention (Fig. 1.23), therefore radiographs need to be read carefully for the presence of calcification or pneumoperitoneum which indicates in utero perforation and the need for surgical intervention without further imaging (Rescorla and Grosfeld 1993). 

Fig. 1.23a,b. Meconium ileus. a,b Intraoperative views illustrating the tenacious nature of the meconium impacted within the distal small bowel loops (arrows) in a patient in which contrast enema failed to solve the obstruction... 

Barki Y, Bar-Ziv J (1985) Meconium ileus ultrasonic diagnosis of intraluminal inspissated meconium. J Clin Ultrasound 13 509-512... 

Burke MS, Ragi JM, Karamanoukian HL et al (2002) New strategies in nonoperative management of meconium ileus. J Pediatr Surg 37 760-764... 

Hussain SM, Meradji M, Robben SG et al (1991) Plain film diagnosis in meconium plug syndrome, meconium ileus and neonatal Hirschsprung s disease. A scoring system. Pediatr Radiol 21 556-559... 

Kamata S, Nose K, Ishikawa S, Usui N, Sawai T, Kitayama Y, Okuyama H, Imura K et al (2000) Meconium peritonitis in utero., Pediatr Surg Int 16 377-379 Kao SC, Franken EA Jr (1995) Nonoperative treatment of simple meconium ileus a survey of the Society for Pediatric Radiology. Pediatr Radiol 25 97-100 Karmazyn B, Werner EA, Rejaie B et al (2005) Mesenteric lymph nodes in children what is normal Pediatr Radiol 35 774-777... 

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