Electrophysiological assessment of polyneuropathic involvement in rheumatoid arthritis: relationships among demographic, clinical and laboratory findings

Abstract

Objectives: The aims of this study were to electrophysiologically evaluate polyneuropathy in rheumatoid arthritis (RA) patients and to examine the relationships among polyneuropathy and demographic, clinical and laboratory findings. Patients and methods: Sixty consecutive patients (51 women and nine men) with a clinical diagnosis of RA were examined electrophysiologically for the evidence of polyneuropathy. Parameters including age, gender, subcutaneous nodules, erosions, joint deformities, laboratory parameters, duration of RA, as well as dose, duration and type of disease modifying anti-rheumatic drug (DMARD) and steroid usage were recorded. RA activity was assessed using a 28-joint disease activity score (DAS28). The functional status of patients was measured using the health assessment questionnaire (HAQ). The symptoms and signs of polyneuropathy were quantified using the neuropathy symptoms score (NSS) and the neuropathy disability score (NDS), respectively. Results: Ten patients (17%, eight women and two men) had polyneuropathic involvement as defined by nerve conduction studies (NCS). Two patients had mild symmetric sensory neuropathy and eight patients had mild symmetric sensorimotor axonal polyneuropathy. There was no significant difference in age, gender, subcutaneous nodules, erosions, joint deformities, rheumatoid factor, as well as dose, duration and type of DMARD and steroid therapy administered. We found a significant relationship among polyneuropathy and duration of RA, DAS28, HAQ, as well as abnormal NSS and NDS values. The durations of RA and DAS28 were also associated with a four-and three-fold increase in the risk of polyneuropathy, respectively. Conclusion: Mild symmetric sensory or sensorimotor axonal polyneuropathies are common in RA patients and it is difficult to distinguish the symptoms of polyneuropathy from those of arthritis. An electrophysiological examination should be routinely carried out especially when patients have had a long disease duration and high scores for DAS28, HAQ, NSS and NDS.