Clinical, neurophysiological, and skin biopsy findings in peripheral neuropathy associated with hepatitis C virus-related cryoglobulinemia

Hepatitis C virus (HCV)-related cryoglobulinemia commonly causes disabling complications including peripheral neuropathy and neuropathic pain. In this prospective clinical, neurophysiological, and skin biopsy study we aimed at assessing clinical characteristics and risk factors of peripheral neuropathy and neuropathic pain in patients with HCV-related cryoglobulinemia. We enrolled 69 consecutive patients with HCV-related cryoglobulinemia. We diagnosed neuropathic pain with the DN4 (Neuropathic Pain Diagnostic) questionnaire, and rated the various neuropathic pains with the Neuropathic Pain Symptom Inventory (NPSI). All patients underwent a standard nerve conduction study to assess A beta-fiber function, laser-evoked potentials to assess A delta-fiber function, and skin biopsy to assess C-fiber terminals. Of the 69 patients studied, 47 had a peripheral neuropathy, and 29 had neuropathic pain. Patients with peripheral neuropathy were older than those without (P < 0.0001). While peripheral neuropathy was significantly associated with the duration of HCV infection (P < 0.01), it was unrelated to the duration of cryoglobulinemia and cryocrit (P > 0.5). The severity of peripheral neuropathy significantly correlated with the duration of HCV infection (P < 0.05). Laser-evoked potential amplitudes were significantly lower in patients with than in those without neuropathic pain (P < 0.05). Conversely, no difference was found in nerve conduction study and skin biopsy findings (P > 0.05). Our findings show that peripheral neuropathy is related to age and HCV infection, rather than to cryoglobulinemia, and neuropathic pain is associated with damage to nociceptive pathways as assessed with laser-evoked potentials; this might be useful for designing more effective clinical interventions for these common HCV related-cryoglobulinemia complications.