Ileocolitis is inflammation of the ileum and colon, most commonly caused by Crohn disease. Other causes of ileocolitis include infections, ischemia, vasculitis, neoplasms, medications (eg, NSAIDs), and infiltrative diseases (eg, amyloidosis, eosinophilic enteritis).

Symptoms include abdominal pain, diarrhea, hematochezia, fever, and weight loss.

• When caused by Crohn disease, complications can occur such as fistulas, bowel obstruction, and abscess formation.
• Infectious colitis can be caused by numerous bacteria including Salmonella, Shigella, Campylobacter, Mycobacterium tuberculosis, invasive Escherichia coli, and Yersinia. Cytomegalovirus can cause ileocolitis in immunocompromised patients.
• Ischemic colitis is caused by acute arterial thrombosis or emboli, venous thrombosis, or hypoperfusion of mesenteric arterial blood flow.