An association between anti-inflammatory medication and internal pelvic fistulas.

Spontaneous internal fistulas involving intestine, rectum, bladder, or vagina in patients without predisposing illnesses were studied. Twelve of 20 (60 percent) were receiving steroids or other anti-inflammatory medication at the time the fistulas developed. Fifteen of the 20 patients subsequently had diverticular disease identified. It is proposed that there is an association between anti-inflammatory medication and fistulas that develop from intestine to other pelvic viscera, spontaneously or in association with colonic diverticula.