A presentation of ulcerative colitis after rituximab therapy in a patient with multiple sclerosis and literature review.

Multiple sclerosis (MS) is one of the most important demyelinating diseases that affects the central nervous system. Its treatment often involves a long-term disease modifying therapy. According to some studies, the prevalence of autoimmune disorders, such as autoimmune hepatitis (AIH) and ulcerative colitis (UC) is higher in MS patients than in the normal population. There are also few studies that have reported the onset of UC after rituximab therapy. The present study presents a report of a 31-years old female patient suffering from aggressive multiple sclerosis, which developed into autoimmune hepatitis during the MS therapy. Thereafter, she received rituximab for the treating both MS and AIH. One week after the third cycle of rituximab (6 doses of 1000 mg), she experienced abdominal pain, fever, and severe bloody diarrhea; finally, she was diagnosed with ulcerative colitis (UC). It seems that the administration of certain immunomodulators or immunosuppressive drugs may have a main role in the exacerbation of some autoimmune diseases.