Dextromethorphan-induced neurologic illness in a patient with negative toxicology findings

Abstract

Neurologists are frequently asked to evaluate patients who are suspected of occult drug use. The standard toxicology screening test obtained in the emergency department will not pick up many drugs of abuse. We present a case of dextromethorphan abuse, not identified on an emergency department visit, explicitly obtained to evaluate suspected dextromethorphan abuse. A 28-year-old man with a history of drug abuse (heroin, crack, alcohol) was referred for evaluation of episodes of abnormal behavior. He was attending an outpatient drug rehabilitation program. Over the preceding month he had experienced five spells during which he felt “flushed, wiped out, tired.” He then experienced light-headedness on standing, headaches, and disorientation, “like being drunk, uncoordinated.” The feeling peaked at about 2 hours and resolved over the next 2 hours. After the onset of one episode his parents noted that he became profoundly sleepy, with psychomotor retardation, and appeared intoxicated. Suspecting drug abuse, they took him to a hospital emergency department (ED). The toxicology screen of urine and blood was negative. He was then brought to a neurologist (J.H.F.). He had a normal neurologic examination and adamantly denied drug use. About 9 hours later …