Chorea disclosing deterioration of polycythaemia vera.

Neurological manifestations occur frequently in polycythaemia. Chorea, however, is a rare complication of the disease. A case of chorea in a patient previously diagnosed with polycythaemia vera is reported. Choreic movements started after measurement of haematological variables showed deterioration. It was considered that this was caused by inappropriate treatment with iron because the chorea was markedly reduced after the two first venesections and normalisation of the packed cell volume and haemoglobin parameters.