Unusual encephalitic illnesses in a child with acute leukaemia in remission: possible role of measles virus and Toxoplasma gondii.

We report a girl who developed an encephalitic illness with visual loss after two years treatment for acute lymphoblastic leukaemia. The visual loss was found to be due to bilateral macular degeneration. She later developed radiological evidence of intracranial calcification and temporal lobe epilepsy. A second episode of encephalitis occurred when she had been off all antileukaemic treatment for three years and this left her with a right hemiparesis. Investigation suggested involvement with both measles virus and Toxoplasma gondii as a cause for these illnesses.