[Updated Diagnosis and Treatment for Chronic Inflammatory Demyelinating Polyradiculoneuropathy Based on the EAN/PNS Guideline 2021].

Chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) includes a number of clinical subtypes. The major phenotype is "typical CIDP," which is characterized by symmetric and "proximal and distal" muscle weakness. Due to historical changes in the concept of CIDP, multifocal motor neuropathy, anti-myelin-associated glycoprotein (anti-MAG) neuropathy, and autoimmune nodopathy were excluded. International guidelines for the diagnosis and treatment of CIDP were first published in 2005 and revised in 2010. In 2021, the guidelines of the European Academy of Neurology (EAN)/Peripheral Nerve Society (PNS) were the second revision, reflecting changes in the disease concept and progress of electrodiagnosis, neuroimaging, and novel treatments. This review introduces the outline of the guidelines in addition to typical CIDP; related chronic demyelinating neuropathies were classified as CIDP variants. The diagnosis of CIDP is based on (1)the phenotype of a typical CIDP or variant, (2)electrophysiological evidence of peripheral nerve demyelination, and (3)exclusion criteria. The first-line treatments for typical CIDP are corticosteroids and immunoglobulin therapy. These guidelines recommend intravenous or subcutaneous immunoglobulin as maintenance therapy, as well as unresolved questions on the evolving concept of CIDP and future treatments.