Nerve ultrasound in the diagnosis of inflammatory neuropathies.

Purpose of review: This review synthesizes the recent advances in the application of nerve ultrasound (US) to inflammatory neuropathies, including chronic inflammatory demyelinating polyradiculoneuropathy (CIDP), multifocal motor neuropathy (MMN), Guillain-Barré syndrome (GBS), neuralgic amyotrophy (NA), Polyneuropathy, Organomegaly, Endocrinopathy, Monoclonal gammopathy, Skin changes syndrome (POEMS), and anti-MAG neuropathy. The aim is to clarify nerve US clinical utility and guide its use in clinical practice.

Recent findings: Nerve US supports differential diagnosis through characteristic sonographic patterns. In CIDP, it aids in identifying atypical forms, predicting treatment response, and may have a role in follow-up. In MMN, nerve US shows diagnostic value. In GBS, it can help differentiate acute-onset CIDP. In NA, alterations can be detected within hours from the onset. Anti-MAG antibody neuropathy lacks well characterized US features. In POEMS and vasculitis, data are scarce and conflicting.

Summary: Nerve US is an established tool for diagnosing neuropathies, as it is noninvasive, accessible, reproducible, and complements electrophysiology. Its role is established in CIDP and its variants, while evidence supports its utility in MMN and the differential diagnosis of neuropathies with an inflammatory-like clinical presentation. In NA, nerve US may outperform neurophysiology. It appears less useful in GBS, POEMS, and anti-MAG neuropathy.