Investigating the Occurrence of Femoral Head Avascular Necrosis in Patient with Multiple Sclerosis Treated with Interferon-Beta

Multiple sclerosis (MS) is a demyelinating inflammatory disease of central nervous system. Avascular necrosis (AVN) of femoral head is reported as an unusual complaint of multiple sclerosis. In this study, occurrence of AVN due to use of interferon-beta remedies was assessed. This was a descriptive cross-sectional study on 6420 cases with relapsing-remitting multiple sclerosis from 2007 to 2017. Recorded information were based on the assessment by expert neurologist, and included demographics, time of disease onset, time of the diagnosis of avascular necrosis (AVN), unilateral or bilateral necrosis, duration and dosage and type of beta-interferon, dosage of oral corticosteroid, and pulse of corticosteroid therapy. The data were analyzed, and descriptive information was expressed as mean, standard deviation, and percentage.   Findings: In this study, 6420 patients with history of relapsing-remitting multiple sclerosis were evaluated. Of them, 4900 cases were treated with interferon-beta which included in the study. Eight patients presented avascular necrosis of femoral head. Mean age of patients was 30.25 ± 10.09 years. 75% of 4900 cases were treated with interferon-beta were women. Mean duration between multiple sclerosis onset and presentation of avascular necrosis was 42.12 ± 28.47 months. 62.5% of patients had unilateral avascular necrosis. 87.5% of cases were under treatment with interferon-beta-1a and the rest 12.5% treated with interferon-beta-1b. Based on the findings of our study, it is possible to hypothesize that use of interferon-beta may have an effect on occurrence of avascular necrosis among patients with multiple sclerosis. The probable mechanisms could be angiogenesis inhibition, vasoconstriction, and small thrombosis formation in arterioles, as well as leukocytoclastic vasculitis. Further studies are recommended