Hirschprung's disease. Coloured barium X-ray of the abdomen of a child with Hirschsprung's disease. The colon (large intestine, orange) has become enlarged and is known as a megacolon. This is a congenital disease where nerves (ganglions) are absent from part of the colon. This prevents peristalsis, the rhythmic movement that propels faeces along the colon, and causes a bowel obstruction that results in a build-up of faeces and a megacolon. Treatment is with a surgical procedure known as 'pull-through', where the portion of the colon that has nerve cells is pulled through and sewn over the part lacking in nerve cells.