Thrombosis as a complication of inflammatory bowel disease in children: a report of four cases.

Thrombosis and thromboembolism have rarely been reported in inflammatory bowel disease (IBD) in children. Four cases of thrombosis, two with apparently serious thromboembolism, are reported in three patients with ulcerative colitis and one with Crohn's disease. Two patients were on steroid treatment at the time of the initial thromboembolic event. Thrombosis may result from a "hypercoagulable state" that occurs in IBD, brought about by a combination of altered clotting factors and the presence of a thrombogenic gastrointestinal mucosa, the risk of which is increased by steroid medications. Children and adolescents with IBD are at risk for serious thromboembolic complications.