Amyloid neuropathy mimicking chronic inflammatory demyelinating polyneuropathy.

INTRODUCTION: Amyloid neuropathy is a rare peripheral neuropathy that classically presents as a progressive sensory neuropathy with prominent autonomic involvement.

METHODS: We describe 5 patients with amyloid neuropathy (familial amyloid polyneuropathy or acquired amyloidosis) who were initially mistaken to have chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) based on history, clinical examination, electrodiagnostic studies, and cerebrospinal fluid (CSF) analysis.

RESULTS: The diagnosis of CIDP had been retained on clinical and electrophysiological grounds for all patients, but we observed no improvement after immunomodulatory treatment. Nerve biopsy confirmed amyloid deposits in nerves, and molecular genetic analysis showed a mutation of the transthyretin (V30M) gene for 3 patients; the 2 other patients had acquired amyloidosis.

CONCLUSIONS: This report emphasizes the need to look for an alternative diagnosis in CIDP patients who do not respond to treatment and to look carefully for symptoms or signs of autonomic involvement in such patients.