Dementia, epilepsy and polyneuropathy in a mercury-exposed patient: investigation, identification of an obscure source and treatment.

We present a patient aged 54 years with early onset of dementia, epilepsy and peripheral polyneuropathy. A mercury intoxication was diagnosed in 2010, chelation therapy with 2,3-dimercaptopropane-1-sulfonate had failed. A source of exposure could not be identified. MRI showed unspecific hyperintense brain lesions in 2015. She was referred for diagnosis and treatment. Neuropsychological testing indicated severe memory loss and nerve conduction speed measurements showed chronic neurogenically changed potentials. Mercury levels in blood and urine and neuron-specific enolase (NSE) were elevated. A detailed patient history revealed a daily application of mercury-containing skin lightening creams for 6 years. Treatment with 2,3-dimercaptosuccinic acid (DMSA) was started, blood mercury levels were falling during treatment. She was discharged with DMSA prescriptions. A renewed MRI revealed unchanged brain lesions. Blood and urine mercury levels and NSE were falling. Memory function had improved qualitatively and quantitatively. 2016 BMJ Publishing Group Ltd.