meconium_ileus

Meconium Ileus:

Dense stools that often present with green and black tar colors excreted after birth.

This mucosal discharge blocks the small intestine, which can require resection.

 


Meconium Ileus


The meconium sometimes becomes thickened and congested in the ileum, a condition known as meconium ileus. Meconium ileus is often the first sign of cystic fibrosis.[5] In cystic fibrosis, the meconium can form a bituminous black-green mechanical obstruction in a segment of the ileum. Beyond this there may be a few separate grey-white globular pellets. Below this level, the bowel is a narrow and empty micro-colon. Above the level of the obstruction, there are several loops of hypertrophied bowel distended with fluid. No meconium is passed, and abdominal distension and vomiting appear soon after birth. About 20% of cases of cystic fibrosis present with meconium ileus, while approximately 20% of one series of cases of meconium ileus did not have cystic fibrosis.[6] The presence of meconium ileus is not related to the severity of the cystic fibrosis.[7]The obstruction can be relieved in a number of different ways.[8]

 


Diagnosis


Intestinal obstruction in infants with meconium ileus is generally evident within 24 to 48 hours after birth. In approximately 20% of patients, particularly patients with complicated meconium ileus, there is a history of maternal excess amniotic fluid in the uterus of the mother. Although meconium ileus is uncommon in premature infants, many of those with meconium ileus are small for gestational age. With meconium ileus, three signs of intestinal obstruction are generally evident:

  1. Abdominal distention
  2. Vomiting of bilious (green, yellow material)
  3. Failure to pass meconium (first stool in the newborn) within 48 hours.

With complicated meconium ileus, patients generally present either at or shortly after birth because of severe abdominal distention that often is associated with breathing problems because the abdomen pushes up on the lungs. At times, the abdominal wall is red and inflamed. In these cases the blood pressure may be unstable and these infants may appear extremely ill. In patients with simple obstruction, one may see varying-sized loops of distended intestine and a “soap bubble” appearance of portions of the abdomen, particularly the right lower area. Other disorders that may share some of these xray findings include Hirschsprung’s disease, ileal atresia, and meconium plug syndrome.


Treatment


Simple Meconium Ileus

The obstructing plugs in patients with meconium ileus may be washed out. With this method, soluble contrast material is used. Regardless of the contrast material used. Approximately 30% of patients with simple meconium ileus may be managed this way, but the success rate varies widely. The remainder of patients require operative management.

In simple meconium ileus, the goal of surgery is to evacuate completely the obstructing plugs and meconium from the small intestine. One method that may be used is to irrigate the intestine and colon clear of plugs of obstructing meconium by making an opening in the small intestine. The opening in the small intestine may then be closed or brought out as an ileostomy. Many surgeons use this approach today. At times, intestinal removal with re-attachment may be needed, provided that all of the plugs can be washed out of the small intestine and colon. An alternative method in patients in whom the small intestine cannot be washed out or whose condition is precarious is the formation of a temporary ileostomy of one of a variety of types. Some surgeons use a double-barreled ileostomy. The downstream ileostomy provides an opportunity for irrigation of obstructing plugs from the downstream intestine. Cumbersome, one can place a tube into the distal stoma.

Complicated Meconium Ileus

Complicated meconium ileus means that the infant has intestine that is blocked or ruptured. Under these circumstances, dead or blocked intestine should be removed, then it is generally best to perform a double- barreled

Postoperatively, careful attention must be given to blood fluid and electrolytes and management of pulmonary complications, such as infection. Patients also require careful nutritional management. Because the pancreas doesn’t work well, supplemental pancreatic enzymes and lipid-soluble vitamins are required. Because of varying degrees of protein, fat, and carbohydrate malabsorption, special formulas such as Pregestimil are generally best. Finally, patients with small bowel stomas may lose large amounts of zinc, magnesium, bicarbonate, and sodium. Failure to thrive occurs unless these patients receive sodium supplementation.


Complications


In addition to pulmonary infection, many patients may have malabsorption, and intestinal obstruction. In older children who do not comply with enzyme supplementation, a meconium ileus–like picture that has been termed meconium ileus equivalent may occur that affects approximately 10% of cystic fibrosis patients. The clinical picture is identical to that of simple meconium ileus in newborns, and enemas are usually sufficient for relief. Additional pancreatic enzyme supplementation then is provided. In the mid-1990s, the use of high concentrations of pancreatic enzymes (mean dose 19,000 U/kg/day) resulted in the development of narrowing of the colon in many CF patients that required resection so that appropriate caution is in order.


References


Wikipedia Sources

5)^ James H Hutchinson Practical Paediatric Problems 4th ed. London: Lloyd-Luke 1975 p. 314 ISBN 0-85324-114-7
6)^ Ali Hekmatnia Meconium Ileus
7)^ Peter G Jones Clinical Paediatric Surgery 2nd ed. Oxford: Blackwell 1976 pp 74-5 ISBN 0-632-00089-9
8)^ Michael S Irish Surgical Aspects of Cystic Fibrosis and Meconium Ileus [1]

O’Neill: Principles of Pediatric Surgery. © 2003, Elsevier.

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