Inspissated, sticky, immobile meconium
causes this transient form of distal
colonic or rectal obstruction in newborns.
The incidence has been estimated
at 1 in 500 to 1000 live births.
The condition is thought to result
from dehydration of the meconium.
Meconium plug syndrome is associated
with prematurity, toxemia of
pregnancy, maternal use of phenothiazines
or tricyclic antidepressants,
hypotonia, hypermagnesemia, hypothyroidism,
and sepsis. Most affected
infants are otherwise healthy. Approximately
15% have cystic fibrosis,
small left colon syndrome, or
Clinical manifestations include
significant abdominal distention and
failure to pass meconium. Plain abdominal
radiographs demonstrate multiple
loops of distended bowel, often with
air-fluid levels. The results of a barium
enema reveal an enlarged rectum with
meconium in the colon. Following
the enema, large pieces of inspissated
meconium plugs are usually passed
and the obstruction is completely relieved.
If the obstruction recurs, cystic
fibrosis and Hirschsprung disease
must be considered in the differential