THE NONSPECIFIC inflammatory bowel diseases (IBDs), ulcerative colitis and Crohn's disease, continue to present challenging problems.1-3 The rising incidence of IBD, especially of Crohn's disease, in recent years has generated increased interest in these disorders and the variety of their local and systemic complications that influence the response to therapy and the course of the illness. The complications may assume primary importance in the health of the patient, while in other cases, they may be the initial overt clinical manifestations of an existing underlying IBD. Some complications, eg, iritis, probably reflect an underlying generalized tissue abnormality. Others, such as "intestinal" arthritis and pericholangitis, may reflect intestinal bacterial overgrowth in Crohn's disease. In yet other circumstances, complications such as skin rashes, bone marrow suppression, superinfections, and electrolyte imbalance are among the many iatrogenic complications associated with the treatment of IBD.
The pathophysiology of IBD complications probably represents several pathogenetic mechanisms.