Sensory neuropathy in patients with cryoglobulin negative hepatitis-C infection

There is growing evidence that hepatitis-C virus (HCV) infection might cause peripheral neuropathy. We aimed to investigate the prevalence, clinical and electrophysiological features of sensory neuropathy in patients with cryoglobulin negative HCV infection. We studied 46 consecutive cryoglobulin negative HCV positive patients (24 of them with and 22 without neuropathic symptoms, NS) and compared to 28 age and gender matched controls. In all patients and controls, clinical neuropathy symptom (NSS) and neuropathy deficit scores (NDS) were assessed and standard nerve conduction velocity (SNCV) and pain related-evoked potentials (PREP) were recorded. Both, SNCV and PREP were abnormal in 13 NS positive patients (13/46, 28%). Abnormal PREP but normal SNCV were found in 5 (5/46, 11%) NS positive and in 2 NS negative patients (2/46, 4%). PREP abnormalities correlated positive with both clinical neuropathy scores (NSS r=0.62; p<0.001; NDS r=0.57; p<0.001), but not with the duration of the disease, current viral load, or the virus subtype. PREP abnormalities were more frequent (16/33, 48.5%) in HCV patients treated with interferon than in therapy naïve patients (4/13, 30.8%); the difference was, however, not significant. In our present study (1) all virus subtypes are capable of inducing neuropathy, (2) no differences were found between interferon therapy and treatment naive patients, (3) the prevalence of peripheral sensory neuropathy including small sensory fibers (20/46, 43.5%) is higher than previously reported and (4) we found that detection of HCV associated neuropathy depends on the evaluation method.