A clinical, serological and neurophysiological study of restless legs syndrome in rheumatoid arthritis.

The restless legs syndrome (RLS), defined by Gibb and Lees criteria, was investigated in patients with RA. RLS symptoms were more frequent in RA patients (25%) than in non-RA controls with OA or seronegative arthropathy (4%). RLS was significantly more common in females. Judged by a variety of clinical and laboratory indices, RA disease severity and current disease activity were greater in patients with RLS than in RA patients unaffected by RLS. In five out of 14 RLS patients undergoing neurophysiological study, delays in the P40 component of posterior tibial somatosensory evoked potentials (SSEPs) were observed suggesting the existence of myelopathy, whilst in another four RLS patients evidence of peripheral neuropathy was found. Though the higher frequency of neurophysiological abnormalities in RA patients with RLS was not statistically significant, possibly because of the small numbers of patients studied, these data suggest that RLS symptoms in RA may reflect the presence of neurological disorder.