Objective: Mononeuritis multiplex is an extra-articular manifestation associated with rheumatoid arthritis. This study set out to investigate its clinical characteristics in Korea. Methods: Clinical characteristics and laboratory data were compared retrospectively by review of medical records between 12 patients with mononeuritis multiplex (case) and randomly selected 116 age-matched patients without mononeuritis multiplex in patients with rheumatoid arthritis (control). Results: Mean age of the case group was 51.8⁑8.4 years old with 7 males and 5 females which showed higher prevalence of male gender compared to the control group (p＜0.05). There was no difference in mean duration of disease between two groups. Upper limbs, lower limbs and both upper and lower limbs were involved in 3, 7 and 2 patients, respectively. Major symptoms were tingling (66.6%), paresthesia (33.3%), pain (33.3%), foot drop (33.3%), or muscle weakness (16.7%). Skin ulceration was accompanied in 3 patients,but vasculitis of other organs was not found. Mean C-reactive protein level in the case group was 7.6⁑6.7 mg/dL, which was higher compared to 2.4⁑3.1 mg/dL in the control group (p＜0.05). Rheumatoid factor was positive in 83.3% of the case, however positive rate and titer showed no significant difference with the control group. There was no difference in other extra-articular manifestations between two groups. Six patients were treated withglucocorticoid and immuno-suppressants and 6 patients with only glucocorticoid1 for 6.8⁑7.1 weeks. Symptoms improved after treatment in 10 patients but, it lasted in 2 patients. Conclusion: Rheumatoid arthritis associated mononeuritis multiplex was more prevalent in males with higher CRP levels, and responded well to medical intervention including glucocorticoid, and immunosuppressants.

Keywords: Mononeuritis multiplex, Rheumatoid arthritis, Vasculitis