Intestinal gas in ulcerative colitis.

Intestinal gas was measured planimetrically on plain abdominal films from 25 healthy subjects and 47 patients with active ulcerative colitis (mild, moderate, severe and toxic megacolon). Compared with controls, significant colonic distention was found in toxic megacolon. Gas in the small bowel was significantly increased in toxic megacolon and in severe colitis but was within the normal range in the mild and moderate forms. Two groups of patients with severe colitis were identified, showing either normal or increased gas content in the small bowel. Two of seven patients in the latter group developed toxic megacolon in spite of intensive medical treatment. Intestinal gas values showed a linear correlation with arterial blood pH, ESR and body temperature. No correlation was found between intestinal gas and other features of severity. It is suggested that an abnormal collection of gas in the small bowel loops associated with metabolic alkalosis corresponds to an early stage of a toxic complication ("impending megacolon").