Mercury is an environmental neurotoxin that, in the United States, is most commonly acquired by ingestion of methylmercury in seafood.1 We report that a significant number of patients with idiopathic axonal neuropathy (IAN) have increased blood mercury levels.
The electronic records of all patients with neuropathy newly seen by one of the authors (N.L.) at the Weill Cornell Neuropathy Center from July 1, 2013, to June 30, 2014, were reviewed, with Weill Cornell Neuropathy Center institutional review board approval. Patient consent was waived as most patients were referred for a single visit and not available for follow-up. Neuropathies were classified as previously described.2,3 Blood mercury levels, determined at a commercial laboratory by mass spectroscopy, were considered elevated if greater than 10 µg/L in comparison with normal control individuals.1 Findings in patients with IAN or idiopathic small-fiber axonal neuropathy were compared with those with chronic inflammatory demyelinating neuropathy or diabetes mellitus using the χ2 test.