Meconium ileus (& Hirschprung, Malrotation)
- Meconium ileus is the third most common
etiology of neonatal small
bowel obstruction, accounting for 9% to 33% of cases.
most patients, meconium ileus is associated with cystic fibrosis; it is
the presenting symptom of this disease in 10% to 25% of cases.
- obstruction is caused by the thick,
tenacious meconium that cannot be
passed beyond the terminal ileum, resulting in the ground-glass appearance on
radiography and dilation of the proximal small intestine.
- meconium contains high concentrations of
protein and mucoproteins and
appears to be related to exocrine
pancreatic insufficiency and abnormal intestinal secretions.
- In some instances, the
inspissated meconium may serve as a
fulcrum for volvulus of the bowel, leading to ischemia, necrosis, and
perforation of the affected intestinal segment in approximately 50% of cases.
- Rarely, the cause of meconium ileus is
mortality associated with meconium
ileus approaches 50%, although this may be higher if peritonitis
differential diagnosis of
meconium ileus is
- meconium plug syndrome
- ileal atresia, colonic atresia
- intestinal pseudo-obstruction
- Hirschsprung disease
- Often the family history of cystic
fibrosis suggests the diagnosis.
- Within the first few days of life -
- fail to pass meconium and vomit bilious
- Due either to the pulmonary complications
of cystic fibrosis or the abdominal distension, infants often develop
- Peristalsis of the intestine is increased,
and the rectal vault is empty.
- Radiographic examination is diagnostic of
meconium ileus in most patients
- minimal air-fluid levels
- sentinel loop of small intestine in
- Intraluminal calcifications are noted in a
small number of patients. T
- ground-glass appearance is due to air
bubbles trapped in the meconium.
Barium enema shows microcolon of the unused large intestine and may
outline the obstructing mass of meconium.
Gastrografin or N-acetyl-cysteine enemas are the treatments of choice for
- Surgical intervention, though rarely
needed, can be necessary when enema therapy is unsuccessful or in a sicker
child in whom the enema cannot be performed or who develops bowel ischemia.
- Hirschprung disease
- Malrotation can present with signs
and symptoms in the neonatal period, and it accounts for 10% of the
obstructions occurring in this age group.
Contrast radiography reveals an
abnormal position of the ligament of Treitz and the presence of small bowel
loops in the right upper quadrant. A normal position of the colon does
not exclude the possibility of a malrotation.
- Meconium peritonitis may complicate
meconium ileus, but it is associated
most often with
- a volvulus of the small intestine
- intestinal atresias
- congenital peritoneal bands.
- Abdominal calcifications are found on
the abdominal flat plate. As stated previously, volvulus can be found in
patients who have meconium ileus, but it also may develop as an independent
disorder. Unless associated with inspissated meconium, there is no
ground-glass appearance on radiography.
Agrons GA, Corse WR, Markowitz RI, Suarez ES, Perry DR.
Gastrointestinal manifestations of cystic fibrosis:
radiologic-pathologic correlation. Radiographics. 1996;16:871-893
Durie PR. Cystic fibrosis. In: Feldman M, Hyman PE, eds.
Gastroenterology and Hepatology: The Comprehensive Visual Reference.
Philadelphia, Pa: Churchill Livingstone; 1997:9.1-9.19
Holsclaw DS, Eckstein HB, Nixon HH. Meconium ileus: a 20-year review
of 109 cases. Am J Dis Child. 1965;109:101-113