Extra-Intestinal Features of Crohn’s Disease

Although Crohn’s disease is a chronic inflammatory disease of the gastrointestinal tract, it can affect multiple organs behaving like a multisystem immune mediated disease. The dysregulated immune system in patients with Crohn’s disease leads to uncontrolled inflammation which primarily affects the gastrointestinal tract but may also affect various extra-intestinal organs. With the increased incidence and prevalence of Crohn’s disease, its extra-intestinal manifestations are increasingly being seen in our clinical practice. The musculoskeletal, mucocutaneous, ophthalmic, hepatobiliary, renal, cardiovascular and pulmonary manifestations of Crohn’s disease have been reviewed in this chapter. Some of these extra-intestinal manifestations are due to systemic inflammation, some of them are due to malabsorption of nutrients and bile salts, and some due to medications given for the treatment of Crohn’s disease. These extra-intestinal manifestations of Crohn’s disease are seen in at least 25% of patients with Crohn’s disease. Some of them correlate well with Crohn’s disease activity but the rest of them have no relation to the activity of Crohn’s disease. Although most of the time the extra-intestinal features are seen after the diagnosis of Crohn’s disease, they can precede or follow the diagnosis of Crohn’s disease. Management of these extra-intestinal manifestations varies as the ones associated with activity of Crohn’s disease respond to remission of Crohn’s disease whereas the ones not related to the activity of Crohn’s disease require specific treatments for those conditions.