The neuropathology of heroin abuse

A broad spectrum of neuropathologic changes are encountered in the brains o f heroin abusers. The main findings are due to infections, either due to ba cterial spread from bacterial endocarditis, mycoses, or from HIV-I infectio n. Other complications include hypoxic-ischemic changes with cerebral edema , ischemic neuronal damage and neuronal loss, which are assumed to occur un der conditions of prolonged heroin-induced respiratory depression, stroke d ue to, for example, thrombembolism, vasculitis, septic emboli, hypotension, and positional vascular compression. Myelopathy is believed to be the resu lt of;ln isolated vascular accident within the spinal cord due to an as yet unknown mechanism. A distinct entity, spongiform leukoencephalopathy, has been described mainly after inhalation of pre heated heroin. A lipophilic t oxin-induced process was considered to be clue to contaminants and to be in duced or enhanced by cerebral hypoxia, but a definite toxin could not be id entified. At the cellular level, abnormalities in signal transduction syste ms and changes of various receptor densities have been reported. The exact etiology of the different neuropathological alterations associated with her oin abuse is still unclear, but may also be related to additional substance s used as adulterants. (C) 2000 Elsevier Science Ireland Ltd. All rights re served.