Chasing "chasing the dragon" with MRI: leukoencephalopathy in drug abuse

Area of Science:

• Neurology
• Radiology
• Toxicology

Background:

• Spongiform leukoencephalopathy is a rare complication of inhaling heated heroin vapor, known as "chasing the dragon."
• Magnetic Resonance Imaging (MRI) findings are crucial for diagnosing this condition, especially in emergency settings with obtunded patients.
• While MR patterns of "chasing" toxicity are often pathognomonic, mimickers exist, necessitating careful evaluation.

Observation:

• This study compares MRI findings in two cases of heroin-induced spongiform leukoencephalopathy with one case of cocaine-induced leukoencephalopathy.
• All three cases presented with diffuse, symmetrical white matter changes on MRI.
• Magnetic Resonance Spectroscopy (MRS) revealed distinct metabolic profiles: heroin users showed increased lactic acid and myo-inositol, decreased N-acetyl aspartate and creatine, and normal choline/lipids, while cocaine users had markedly increased lactic acid and lipids.

Findings:

• MRI findings in all three cases were suggestive of spongiform leukoencephalopathy.
• MRS profiles can help differentiate heroin-induced toxicity from other inhaled substance toxicities.
• Discordance between MR perfusion and MRS in one case suggests impaired cellular energy metabolism in heroin toxicity.
• MR changes in spongiform leukoencephalopathy from heroin use can progress even with abstinence and clinical improvement, indicating an evolving injury process.

Implications:

• Accurate diagnosis of spongiform leukoencephalopathy is vital in emergency medicine, particularly for patients unable to provide a history.
• MRS serves as a valuable tool in distinguishing heroin toxicity from other causes of leukoencephalopathy.
• Understanding the evolving nature of MR findings is important for patient management and prognosis.