Toxic leukoencephalopathy after heroin abuse without heroin vapor inhalation: MR imaging and clinical features in three patients.

BACKGROUND AND
PURPOSE: Toxic leukoencephalopathy has been associated with illicit heroin vapor inhalation. Despite the nonspecific and variable clinical presentation of these patients, they show typical radiologic findings. Previous studies evaluated typical radiologic findings with symmetric infratentorial hyperintense signal changes and similar alteration in the posterior limb of the internal capsule, the splenium of corpus callosum, the medial lemniscus and the lateral brainstem. In context with the reviewed literature, a series of another three cases with toxic leukoencephalopathy after heroin abuse other than vapor inhalation is presented. PATIENTS AND METHODS: All three patients underwent magnet resonance imaging (MRI) including additional diffusion- weighted imaging and apparent diffusion coefficient maps. Clinical and laboratory findings were recorded.
RESULTS: MRI of all three patients revealed similar symmetric supratentorial hyperintense signal changes involving the frontal, parietal, occipital and temporal lobes. The cortex was spared and the subcortical U fibers were partially involved. Further, the brainstem and the cerebellar white matter were not affected.
CONCLUSION: Toxic leukoencephalopathy without involvement of the cerebellum and brainstem is a rare complication of heroin abuse. The pattern of heroin-induced toxic leukoencephalopathy on MRI might not only be related to an unknown adulterant, but also to the mode of drug administration.