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41 y.o. male with ALOC.
Findings
Extensive symmetric hyperintensity involving the cerebellum, brain stem, internal capsule, and cerebral white matter.
Symmetric hyperintensity in the cerebellar white matter and peduncles, the corticospinal tracts, and the cerebral white matter, particularly posteriorly.
Selective involvement of the posterior limb of the internal capsule and sparing of the subcortical white matter.
Differential Diagnosis
Tumor?
Infection?
Congenital?
Metabolic?
Trauma?
Vascular?
Environmental?
Toxic Leukoencephalopathy 2° Heroin Vapor Inhalation a.k.a. “Chasing the Dragon”
Toxic Leukoencephalopathy 2° Heroin Vapor Inhalation
Toxic leukoencephalopathy may be caused by a wide variety of agents, including occupational or environmental exposure, substance abuse, radiation, and chemotherapy.
Clinical and radiologic findings often nonspecific.
Accurate diagnosis may be difficult without a known history of exposure to a particular agent.
Toxic Leukoencephalopathy 2° Heroin Vapor Inhalation
The particular chemical that causes heroin inhalation toxicity is unknown but is believed to be an impurity that is activated by heating the drug over aluminum foil.
Heroin use and intoxication are associated with a number of effects on the central nervous system, including hypoxic brain injury, transverse myelitis, and brain abscess.
Imaging features of these manifestations, however, are nonspecific with regard to cause .
Toxic Leukoencephalopathy 2° Heroin Vapor Inhalation
Leukoencephalopathy due to inhalation of heroin pyrolysate was first described by researchers in the Netherlands in 1982.
Clinically, three stages, progressing from cerebellar signs and motor restlessness to pyramidal and pseudobulbar signs, and to a terminal stage characterized by spasms, hypotonic paresis, and ultimately death.
Symmetric spongiform degeneration occurs, particularly in the cerebral and cerebellar white matter and in corticospinal and solitary tracts.
Toluene Abuse
Chronic toluene abuse: hyperintense white matter lesions and thalamic hypointensity on T2-weighted images, which is associated with the duration of abuse.
Toxic Leukoencephalopathy 2° Heroin Vapor Inhalation
MR spectroscopy: reduced N-acetyl aspartate and increased cerebral lactate
Mitochondrial toxicity ?
Toxic Leukoencephalopathy 2° Heroin Vapor Inhalation
The term "chasing the dragon" appears to have originated in China in the 1920s.
Popular mechanism of heroin administration in the 1950s in Hong Kong because the drug was cheap but impure.
Small quantity of powder is placed on aluminum foil, which is then heated underneath with a lighter or matches. Heroin liquefies into a reddish brown glob, moving around on the foil & emitting a white vapor. The glob or "dragon" is "chased" with the lighter underneath while the vapor is sucked through a straw or pipe.
Toxic Leukoencephalopathy 2° Heroin Vapor Inhalation
Keogh, Andrews, Spacey, et al. Neuroimaging Features of Heroin Inhalation Toxicity: "Chasing the Dragon" Am. J. Roentgenol., Mar 2003; 180: 847 - 850.
