Restless Legs Syndrome In Peripheral Neuropathy

Abstract

Restless legs syndrome (RLS) is increasingly recognized as a manifestation of various forms of peripheral neuropathy, and in particular in association with amyloidosis, uremia, diabetes, cryoglobulinemia, and Charcot‐Marie‐Tooth disease type 2. A previous study demonstrated a 5% prevalence of RLS in unselected neuropathies, but did not elucidate factors influencing the occurrence, or not, of RLS in peripheral neuropathy. We studied a series of unselected neuropathic patients to assess the prevalence of RLS, and to define the features of peripheral neuropathy associated with RLS. In a population of 70 consecutive patients with various forms of peripheral neuropathy (polyneuropathy in 65 cases, multiple mononeuropathy in 5 cases) we found RLS in 20 cases (28.6%). In particular, RLS was more often associated with cryoglubolinemic neuropathy (5/13), diabetic neuropathy (4/12), Charcot‐Marie‐Tooth disease (4/18), and chronic idiopathic axonal polyneuropathy (2/6). RLS was usually associated with a neuropathy of axonal type, and the onset of RLS was 0–10 (median 1) years after the onset of neuropathy; in 9 cases, RLS was an initial manifestation of neuropathy. Patients with pure sensory or mainly sensory neuropathy had RLS more often than patients with other patterns of neuropathy (13/37 vs. 7/33). Severity of neuropathy, as judged by Rankin score, did not differ in patients with or without RLS (13/20 with Rankin grade 2 or more, vs. 36/50). Prevalence of RLS in our population of neuropathic patients was higher than previously reported. Thus RLS may be viewed as a quite common manifestation of peripheral neuropathy in general, although more common in some forms, and it represents a treatable neuropathic symptom. Mechanisms of RLS are elusive, however a role of sensory inputs is supported by its greater incidence in association with sensory neuropathies.