Clinical and electrophysiological characteristics of symmetric polyneuropathy in a cohort of systemic lupus erythematosus patients.

OBJECTIVE Peripheral neuropathy in systemic lupus erythematosus (SLE) is heterogeneous and its commonest pattern is symmetrical polyneuropathy. The aim of this study was to describe the prevalence, clinical and electrophysiological features, disease associations and effects on function and quality of life of polyneuropathy in SLE patients, defined using combined clinical and electrophysiological diagnostic criteria. METHODS Consecutive SLE patients seen at the University of Malaya Medical Centre were included. Patients with medication and other disorders known to cause neuropathy were excluded. Demographic, clinical and laboratory data were obtained using a pre-defined questionnaire. Function and health-related quality of life was assessed using the modified Rankin scale and the SF-36 scores. Nerve conduction studies (NCS) were carried out in both upper and lower limbs. Polyneuropathy was defined as the presence of bilateral clinical symptoms and/or signs and bilateral abnormal NCS parameters. RESULTS Of 150 patients, 23 (15.3%) had polyneuropathy. SLE-related polyneuropathy was mainly characterized by sensory symptoms of numbness/tingling and pain with mild signs of absent ankle reflexes and reduced pain sensation. Function was minimally affected and there were no differences in quality of life scores. NCS abnormalities suggested mild length-dependent axonal neuropathy, primarily in the distal lower limbs. Compared to those without polyneuropathy, SLE-related polyneuropathy patients were significantly older but had no other significant demographic or disease associations. CONCLUSIONS SLE-related polyneuropathy is a chronic, axonal and predominantly sensory neuropathy, associated with older age. Its underlying pathogenetic mechanisms are unknown, although a possibility could be an increased susceptibility of peripheral nerves in SLE patients to effects of aging.