Abstracts of the 8th Meeting of the Italian Peripheral Nerve Study Group: 73

Cryoglobulinemic neuropathy is probably the commonest form of vasculitic neuropathy in Mediterranean countries, as usually related to the widespread hepatitis C virus (HCV) infection. We describe the spectrum of manifestations in a large series of patients with cryoglobulinemic neuropathy, also analyzing the impact of comorbid factors, which are quite frequent in HCV-related mixed cryoglobulinemia. The cohort included 60 patients (10 men, 50 women) with peripheral neuropathy associated with mixed cryoglobulinemia as main or sole cause (type 2 in 36 cases, type 3 in 4, not typized in 20), HCV-related in all patients but 8 (3 men and 5 women). Median age of patients was 65 years (range 41–85), and median age at onset of neuropathy was 59 (range 40–84). Peripheral neuropathy represented an onset manifestation of mixed cryoglobulinemia in about half patients. The most frequent clinical pattern was pure sensory neuropathy in 40 patients, including 4 patients with prominent ataxia; sensory neuropathy was asymmetrical in distribution in 9 patients, and in 14 patients sensory action potentials (SAPs) of the sural nerve were normal, suggesting selective involvement of the small sensory fibers. The remaining patients had sensorimotor neuropathy (15 cases) and mononeuropathy multiplex (5 cases). Positive sensory symptoms and restless legs syndrome were the most common manifestations. Neurophysiological study showed axonal degeneration of varying severity in all patients. In 20 patients, additional causes of neuropathy were present, including type 2 diabetes (5 patients), glucose intolerance (6 patients), non-Hodgkin lymphoma (3 patients), and alcohol (2 patients). With respect with this subset of patients, in “pure” cryoglobulinemic neuropathy there was more often a pattern of sensory neuropathy (31/40 vs. 6/20; p = 0.001), with more frequent asymmetrical distribution (9 vs 0; p = 0.05) and small fiber involvement (11 vs 3). Severity of neuropathy, as judged on the basis of the Rankin scale and of neurophysiological changes, was similar in the two subgroups. Our study confirms that sensory neuropathy, often asymmetrical, is the most common clinical pattern in cryoglobulinemic neuropathy, and is consistently present in pure cryoglobulinemic neuropathy rather than in patients with other associated causes of neuropathy; in these latter, paradoxically, clinical and neurophysiological impairment seems not greater than in pure cryoglobulinemic neuropathy.