Fatal toxic leukoencephalopathy: clinical, radiological, and necropsy findings in two patients.

BACKGROUND Toxic leukoencephalopathy has been described with inhalation and intravenous consumption of heroin and cocaine. The clinical picture varies widely but the imaging and histological features are characteristic. Magnetic resonance imaging (MRI) typically reveals diffuse bihemispheric white matter lesions. Histologically there is extensive spongiform degeneration of the cerebral white matter. OBJECTIVE To report two cases of fatal toxin associated leukoencephalopathy, along with detailed imaging and neuropathological studies. RESULTS MRI revealed diffuse white matter changes. Histologically there was widespread confluent vacuolar degeneration of the deep white matter. In both cases, there was sparing of the brain stem and cerebellar white matter. There was evidence of severe and extensive axonal injury. CONCLUSIONS This pattern of radiological involvement and histological findings has not previously been reported and may reflect the presence of a yet unidentified impurity.