Controversies in the diagnosis of chronic inflammatory demyelinating polyneuropathy

Purpose of review Despite decades of clinical recognition, the diagnosis of chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) remains fraught with uncertainty. This review examines major areas of ongoing controversy in the diagnostic evaluation of CIDP, focusing on recent changes to electrodiagnostic criteria, disease boundaries, and emerging concepts of axonal damage. Recent findings Recent literature highlights three key areas of diagnostic uncertainty: the evolution and limitations of electrodiagnostic criteria; the diagnostic boundary between CIDP and antimyelin-associated glycoprotein (anti-MAG0 antibody neuropathy; and the recognition of CIDP cases that do not fulfil electrodiagnostic criteria, raising interest in axonal variants and the potential role of biomarkers such as neurofilaments. Across these domains, discrepancies between empirical evidence and expert-based guidelines persist, contributing to misdiagnosis and treatment variability. Summary Current CIDP criteria, though improved, remain partly based on expert opinion rather than empirical validation. The clinical heterogeneity of CIDP and its overlap with mimicking disorders further complicate diagnosis. A broader, more flexible diagnostic framework - integrating electrophysiology, biomarkers, and treatment response - is essential to enhance diagnostic accuracy and guide therapy. Future research should focus on refining criteria to strengthen electrodiagnostic standards and better accommodate atypical and axonal presentations.