Clinical Scenario:
15-year-old boy is brought to the emergency department by his parents because of sudden agitation and unusual behavior. He is restless, has dilated pupils, dry flushed skin, tachycardia (132/min), hypertension and hyperthermia (39.2°C). He is confused and intermittently hallucinating. There is no history of trauma or fever before presentation. His parents report that he has recently been associating with a new group of friends.
Which substance is the most likely cause of this presentation?
A. Cannabis
B. Cocaine
C. Heroin
D. Opioids
E. Sedative-hypnotics
Correct answer & Explanation:
Explanation
Correct answer: B. Cocaine
The adolescent has a classic sympathomimetic toxidrome characterized by:
- Agitation and confusion
- Hallucinations
- Mydriasis
- Tachycardia
- Hypertension
- Hyperthermia
- Dry, flushed skin
Cocaine blocks the reuptake of norepinephrine, dopamine and serotonin, producing marked sympathetic stimulation. Severe toxicity can lead to seizures, arrhythmias, myocardial ischemia, hyperthermia and intracranial hemorrhage.
The combination of agitation + mydriasis + hypertension + tachycardia + hyperthermia should suggest a sympathomimetic drug such as cocaine or an amphetamine.
Exam pearl:
Mydriasis + agitation + tachycardia + hypertension + hyperthermia → sympathomimetic toxicity.
Cocaine toxicity is primarily managed with supportive care and benzodiazepines, particularly for severe agitation, seizures and sympathetic overactivity. External cooling is important for significant hyperthermia.
You can practice another MCQ on Substance Abuse.
References
- Merck Manual Professional – Cocaine Toxicity
- Merck Manual Professional Edition. Common Toxic Syndromes – Sympathomimetic toxidrome.
