[Peripheral neuropathy and hepatitis C virus infection: more than cryoglobulinemia].
PURPOSE: To study characteristics of peripheral neuropathies associated with hepatitis C virus infection. METHODS: A study of two groups of four patients with peripheral neuropathy and infected with hepatitis C virus, and a literature review. RESULTS: We observed four cases of peripheral neuropathy in patients with hepatitis C virus infection with persistent negativity of mixed cryoglobulinemia, and with no purpura, rheumatoid factor, or low C4 level. Neuropathy improved with treatment in three patients between 8 and 28 months after treatment was begun. We report four other observations of peripheral neuropathy with mixed cryoglobulinemia. Worsening of peripheral neuropathy was observed 2 to 13 weeks after initiation of interferon alpha despite improvement of hepatic parameters. After stopping interferon, peripheral neuropathy worsened (one case), stabilized (one case), or improved (two cases). DISCUSSION: In patients infected with hepatitis C virus, peripheral neuropathy can be due to mixed cryoglobulinemia, periarteritis nodosa, and perhaps hepatitis C virus itself as suggested by our first observations. Low doses of interferon alpha may worsen peripheral neuropathy in patients with mixed cryoglobulinemia, as suggested in our later observations.