A condition in which one part of the intestine becomes pushed or telescoped into the adjoining portion.

It occurs mainly in infants under one year and usually starts at the lower end of the ileum. It may result when overactive wave contractions (peristalsis) of the intestine drive a segment of the bowel inside the adjacent segment. Further peristaltic movements may aggravate the condition so that more of the intestine becomes involved. The sudden intestinal obstruction causes severe abdominal pain. The infant has attacks of screaming and draws up its legs. The face becomes very pale when the pain is most intense and brightens in the intervals between spasms. Vomiting starts early and is severe and repeated. After the first bowel movement, the infant passes only red jelly-like clots of pure blood and mucus from the bowel.

Examination of the abdomen by the doctor usually reveals a sausage-like mass.

Prompt surgical treatment is necessary to pull the telescoped portion of the intestine back to its normal position. If the intestine is gangrenous, as happens in some cases, surgical removal of the affected part is necessary.