乌鸦传媒

Chasing the dragon, a method of inhaling heroin, is emerging as a global phenomenon and needs better diagnostic criteria, according to a new review.

Chasing the dragon can lead to aggressive toxic leukoencephalopathy, movement disorders, and hydrocephalus, wrote Ciro Ramos-Estebanez, MD, PhD, of University Hospitals Cleveland Medical Center, and colleagues in .

"We believe heroin inhaled via chasing the dragon hurts the brain through a mechanism quite distinct from other routes," Ramos-Estebanez told 乌鸦传媒. "Chasing the dragon damages white matter to the point that eventually the affected brain tissue, when seen under the microscope, look like a sponge, with irregular holes throughout," and may lead to symptoms ranging from long-term cognitive deficits to death.

involves heating heroin on a metal (usually aluminum) foil with a controlled flame to produce a vapor that is inhaled. Although injecting opioids remains the main route of abuse in the U.S., inhaled heroin is a rapidly spreading method. Inhaled heroin was involved in hospital admissions in 2014.

Some heroin users perceive that inhaling is safer than injecting, since it doesn't carry infectious consequences like HIV, or hepatitis B and C, Ramos-Estebanez noted. "Worldwide, this is becoming a lucrative form of heroin abuse, especially among young individuals, and people who transition from pill-based addiction," he said.

To analyze current evidence and characterize chasing the dragon for clinical practice, the authors searched existing literature, defining acute chasing the dragon heroin neurotoxicity as the presence of all the following factors:

Positive heroin testing

• Confirmed report of heroin inhalation by the patient, next of kin, or witness
• Statement or description of chasing the dragon by the author
• Clinical syndrome description to interpret the severity of disease
• Supportive radiological or pathological findings

While the literature did not provide many detailed reports about prognosis and outcomes, the authors observed that 17 of 17 individuals (100%) with mild cases survived and had a modified Rankin score of ≤2. Prognosis in moderate cases was unclear, but 41 of 42 such patients (98%) survived. Only eight of 24 with severe cases (33%) survived. Detailed neuropsychological descriptions in survivors were scarce and confounded by long-term heroin use.

In 11 followed-up cases, nine patients were administered coenzyme Q10; five of them improved and four remained unchanged or deteriorated.

Diagnostic criteria and standard reporting could improve literature limitations and identify patients for therapeutic trials, Ramos-Estebanez's group noted. They , all of which involved the presence of a clinical syndrome suggestive of clinical leukoencephalopathy, positive heroin testing, and a confirmed report of the inhalation method.

"Toxic leukoencephalopathy is an important consideration in the construction of the differential for a 'found down' patient with known or suspected opiate use," observed Natalie Achamallah, MD, of Santa Barbara Cottage Hospital in California, who was not involved in the review. "This is especially true for patients who do not have an identifiable or prolonged apneic time."

"Our institution has experience with a handful of cases of abrupt-onset toxic leukoencephalopathy due to inhaled heroin use," Achamallah told 乌鸦传媒. "While most cases of toxic leukoencephalopathy in the literature describe a slowly progressive course ending in coma or death, it is possible that with increasing recognition and testing, a new sub-population of acute toxic leukoencephalopathy cases may be identified." In two of three cases, patients had dramatic, but slow, recoveries, Achamallah and colleagues reported.

Review limitations included inconsistencies in the literature; outcome measures were scarce and lacked details. But while their recommendations are subject to interobserver variation, spectrum bias, and reference bias, "the risk of not recognizing chasing the dragon leukoencephalopathy exceeds the demerit of a false-positive diagnosis in patients who otherwise might have benefited from targeted therapy," the authors wrote.

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