Use the toxidrome and imaging pattern to separate stimulant toxicity from structural neurologic disease. MDMA, ketamine, and cocaine adulterants each have distinct clues that should guide the next step.

Levamisole is a common cocaine adulterant that can trigger patchy demyelination and sudden neurologic deficits; It can also cause ANCA-positive vasculitis with systemic inflammatory features; MDMA toxicity can cause serotonin syndrome, hyponatremia, hyperthermia, liver injury, and dystonia; Ketamine causes rapid-onset dissociation, hallucinations, agitation, or sedation; Cocaine adulterants and synthetic club drugs can have unpredictable neurologic toxicity