Coexistence of hyperthyroidism and ulcerative colitis: report of 4 cases and a review of the literature.

Four cases of coexisting hyperthyroidism and ulcerative colitis are presented. In two patients the diseases appeared simultaneously, in one the diagnosis of ulcerative colitis preceded the diagnosis of hyperthyroidism, while in the fourth the diagnosis of hyperthyroidism preceded the diagnosis of ulcerative colitis. Hyperthyroidism intensifies the symptoms of ulcerative colitis and impairs response to therapy. Treatment of both diseases should be conservative. There is no clear explanation for the concurrent existence of the two diseases, although immunological mechanisms seem to play the most significant role. The clinician must bear in mind that coexistence of hyperthyroidism and ulcerative colitis in some patients, although infrequent, nevertheless is a reality, which obviously is very important for the patient's outcome.