Progressive multifocal leukoencephalopathy associated with prolonged hemodialysis treatment.

The association of progressive multifocal leukoencephalopathy (PML) with prolonged hemodialysis treatment (PHT), not previously reported, was observed in a 56-year-old Japanese man who received PHT for 11 years. He suffered from recurrent bouts of fever and progressive neurological signs, such as irritability, speech disturbance, gait disturbance and dysphagia for seven months, and finally fell into a deep coma and died. Clinical signs and symptoms were highly suggestive of progressive dialysis encephalopathy. Necropsy revealed that the PML mainly involved the brainstem and cerebellar white matter. The aluminium content of the brain tissue was lower than that of controls. Possibly the virus causing PML is one of the causes of progressive dialysis encephalopathy, since clinically PML is not easily distinguished from progressive dialysis encephalopathy. It is essential to differentiate PML of viral etiology from progressive dialysis encephalopathy of unknown cause.