[A case of chronic inflammatory demyelinating polyradiculoneuropathy after treatment with pegylated interferon α-2a in a patient with chronic hepatitis B virus infection].

We report the case of a 42-year-old man with chronic hepatitis B virus infection who developed weakness and paresthesia in the extremities 2 months after administration of pegylated interferon (Peg-IFN)α-2a. Nerve conduction studies conducted 6 months after onset showed abnormal temporal dispersions in both tibial nerves. We diagnosed chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) resulting from treatment with Peg-IFNα-2a. Neurological symptoms were prolonged despite suspension of the treatment. Subsequent treatment with intravenous immunoglobulin improved both clinical symptoms and temporal dispersion. IFNα-induced CIDP is rare, but can reportedly progress even after interruption of IFN-α without immunotherapy. Patients presenting with polyneuropathy after initiation of IFN-α thus require close attention.