Megacystis-Microcolon-Intestinal Hypoperistalsis Syndrome

Megacystis-microcolon hypoperistalsis syndrome (MMIHS) was first described in 1974 by Berdon in 5 female infants, 2 of whom were sisters [1].MMIHS is a rare congenital disease with high mortality rate[2].

MMIHS has been found predominantly in females with an approximate 4:1 female to male ratio [3,4]. It is characterized by abdominal distention caused by a grossly enlarged, non-obstructed bladder (megacystis). The small intestine is malrotated and often short and distended followed by a hypoperistaltic microcolon.

 MMIHS presents clinically at birth with bilious vomiting, an overdistended abdomen, and absent or decreased bowel sounds. Further findings include a failure to feed or to pass stool despite many attempts to stimulate bowel activity with various cathartic medications.

 The cause and pathogenesis of this disorder are not fully understood, and MMIHS is not a form of intestinal pseudo-obstruction [7,8]. Histologic examination has frequently revealed findings consistent with smooth muscle intestinal myopathy [3,7]. These findings include extensive transmural fibrosis, thinning of the longitudinal smooth muscle layer, connective tissue proliferation within intestinal smooth muscle and absent immunoreactivity in the longitudinal layer [7,8].  The detrusor muscle in MMIHS is strikingly abnormal and is the likely cause of voiding dysfunction in the affected patients [9].  The affected patients are unable to void spontaneously [10]. Cystostomy is always required.

The prognosis is poor and treatment has been shown to be ineffective. MMIHS is a lethal syndrome in the first years of life and there are no reported cases of long term survivors.