Abstract
Toxic leukoencephalopathy associated with heroin inhalation has been extensively described in the literature. This syndrome is characterized by progressive motor symptoms and dysautonomia that develop over weeks to months. We present three cases of abrupt-onset inhaled heroin-associated toxic leukoencephalopathy, a previously undescribed entity. These likely represent a subset of "found down" patients with acute neurologic changes not attributable to hypoxemic encephalopathy. All three had magnetic resonance imaging findings characteristic of toxic leukoencephalopathy, which has a relatively favorable prognosis. Prolonged unresponsiveness in patients "found down" after heroin overdose is often attributed to hypoxic brain injury. Brain magnetic resonance imaging is not generally included as part of routine workup. It should, however, be considered in patients with suspected inhaled heroin use due to the relatively favorable prognosis of toxic leukoencephalopathy. This is especially relevant in the setting of the current opioid epidemic and related increase in overdose-related intensive care unit admissions. The result may have significant impact on decisions about therapeutic options or continuation of care.