Patients with Hirschsprung's disease may suffer from enterocolitis, either before or after corrective surgery. They have an underlying dysmotility of the colon which leads to stasis of their stool, subsequent bacterial overgrowth and then secretory diarrhea. Sometimes the enterocolitis gives less dramatic symptoms such as failure to thrive and intermittent cramping and abdominal pain.
The treatment of enterocolitis when it is severe enough to warrant inpatient care involves aggressive colonic irrigations, intravenous antibiotics (Metronidazole) and intravenous hydration.
The rationale of rectal irrigations is to clean the colon of stool to prevent "stasis" of stool in the colon. Your child should be irrigated with normal saline solution beginning with 10-20ml at a time for a total of 20ml/kg. If the saline is returned during the irrigation process, then this volume can be repeated.