Informal gold miners with mercury toxicity: Novel asymmetrical neurological presentations

Mercury is a highly toxic heavy metal that may cause neurological, respiratory, gastrointestinal and dermatological illnesses. Previously described neurological manifestations of mercury toxicity are symmetrical, and include a pancerebellar syndrome, generalised seizures and encephalopathy. Mercury is used in the gold mining process, and in artisanal or illicit gold mining, often without necessary protection. Here we describe the cases of two artisanal gold miners from western Johannesburg, South Africa, who presented with atypical neurological manifestations of mercury toxicity. Patient 1 presented with focal seizures, an asymmetrical cerebellar syndrome and an acute encephalopathy. Patient 2 had unilateral cerebellar ataxia. Both patients had toxic mercury levels, with no other cause identified for their symptoms. Patient 1 responded well to chelation therapy, but patient 2 refused admission and further medical treatment. The neurological manifestations of mercury toxicity are typically symmetrical, whereas our two patients presented with markedly asymmetrical features. It is important to maintain a high index of suspicion for mercury poisoning, even in patients with atypical and unilateral or asymmetrical presentations. A prompt diagnosis and the commencement of early chelation therapy have the potential to produce good outcomes.