Ataxia and cranial neuropathies from subcutaneously injected elemental mercury

CONTEXT. Although neurological toxicity from elemental mercury vapor and organic mercury exposure has been commonly reported in the literature, it is rarely reported from soft tissue injection of elemental mercury. We present a case of neurological dysfunction from subcutaneous injection of elemental mercury. CASE DETAILS. A 35-year-old Latin American man subacutely developed gait ataxia, diplopia, and vomiting 1 year after subcutaneous injection of elemental mercury, a practice common in Afro-Caribbean and Latin-American cultures. Physical examination showed an indurated plaque on his right shoulder at the injection site, left third nerve and bilateral sixth nerve palsies, nystagmus, dysarthria, and gait and limb ataxia. The patient's serum and 24-h urine mercury levels were significantly elevated; he underwent excision of the mercury reservoir and chelation with dimercaptosuccinic acid but experienced only mild improvement after 1 year. DISCUSSION. Neurological sequelae from elemental mercury, specifically cognitive dysfunction, tremor, cortical myoclonus, and peripheral neuropathy, have been reported but cranial neuropathies, ataxia, cerebrospinal fluid pleocytosis, and the presence of anti-Purkinje cell type-Tr antibody have not. Treatment involves removal of any existing mercury reservoir and chelation; however, improvement in neurological dysfunction after treatment has rarely been reported in the literature.