A young teenage boy with a history of drug abuse had been instilled with a shot of intravenous cocaine at a party. He is rushed to the emergency room by his friends. Some of the symptoms were diaphoresis, headache, and acute coronary spasm. Which of the following symptoms noted would go against the likely diagnosis of cocaine poisoning?

Explanation

## Correct Answer: A. Bradycardia Cocaine is a potent sympathomimetic agent that causes acute catecholamine excess through inhibition of monoamine reuptake (dopamine, norepinephrine, serotonin). The cardinal cardiovascular and neurological manifestations are **tachycardia, hypertension, hyperthermia, agitation, and coronary vasospasm** leading to acute myocardial ischemia. Bradycardia is fundamentally incompatible with acute cocaine toxicity because cocaine's mechanism of action is entirely sympathomimetic—it increases circulating catecholamines and directly stimulates α- and β-adrenergic receptors. A bradycardic response would indicate parasympathomimetic or vagal dominance, which is the opposite of cocaine's pharmacological profile. In the clinical scenario presented, the patient exhibits diaphoresis (sympathetic activation), headache (hypertensive crisis), and acute coronary spasm (catecholamine-induced vasospasm)—all classic cocaine toxidrome features. Bradycardia would be an atypical and contradictory finding that should prompt reconsideration of the diagnosis. This question tests understanding of cocaine's mechanism as a sympathomimetic and recognition that tachycardia (not bradycardia) is a hallmark sign of acute cocaine poisoning in Indian emergency medicine practice. ## Why the other options are wrong **B. Agitation** — Agitation is a classic and expected manifestation of acute cocaine toxicity. Cocaine stimulates the central nervous system via dopamine and norepinephrine excess, producing restlessness, anxiety, tremor, and agitation. This is a cardinal feature of the cocaine toxidrome and would be consistent with the diagnosis, not against it. NBE includes this as a trap for students who confuse sympathomimetic CNS effects with parasympathomimetic effects. **C. Hyperthermia** — Hyperthermia is an expected and dangerous complication of acute cocaine poisoning. Cocaine increases metabolic rate, causes intense sympathomimetic stimulation, and impairs heat dissipation through vasoconstriction. Hyperthermia is a hallmark sign of severe cocaine toxicity and may progress to life-threatening rhabdomyolysis and disseminated intravascular coagulation. This finding supports, not contradicts, the diagnosis of cocaine poisoning. **D. Myocardial ischemia** — Myocardial ischemia is a direct consequence of cocaine's dual mechanism: increased myocardial oxygen demand (via tachycardia and hypertension) combined with coronary vasospasm (via α-adrenergic stimulation). Acute coronary spasm is explicitly mentioned in the stem as already present. Myocardial ischemia is a hallmark cardiac complication of cocaine abuse and is entirely consistent with the diagnosis, not contradictory to it. ## High-Yield Facts - **Cocaine toxidrome**: tachycardia (not bradycardia), hypertension, hyperthermia, mydriasis, agitation, diaphoresis, and coronary vasospasm. - **Mechanism**: cocaine blocks reuptake of dopamine, norepinephrine, and serotonin → sympathomimetic excess → α- and β-adrenergic overstimulation. - **Bradycardia is pathognomonic for parasympathomimetic or vagal toxidromes** (organophosphates, carbamates, cholinergic agents)—never cocaine. - **Acute coronary syndrome in cocaine abuse**: caused by increased myocardial O₂ demand + coronary vasospasm; can occur even in young patients with normal coronaries. - **Management**: benzodiazepines (diazepam/lorazepam) for agitation; calcium channel blockers (nifedipine) or nitrates for coronary vasospasm; avoid β-blockers (unopposed α-adrenergic effects). ## Mnemonics **COCAINE Toxidrome (Sympathomimetic)** **C**ardiac tachycardia, **O**ver-stimulation, **C**oronary spasm, **A**gitation, **I**schemia, **N**eurological hyperactivity, **E**levated temperature. Remember: all sympathomimetic—never bradycardia. **Bradycardia = WRONG for Cocaine** **SLOW** = Sympathomimetic Lacks Opposite (bradycardia) With cocaine. Bradycardia = parasympathomimetic (organophosphates, muscarine). Cocaine = FAST heart. ## NBE Trap NBE pairs cocaine with "acute coronary spasm" and "diaphoresis" in the stem to anchor students in the correct diagnosis, then tests whether they understand that **tachycardia (not bradycardia) is the expected cardiovascular response**. The trap is including bradycardia as an option to catch students who confuse sympathomimetic with parasympathomimetic toxidromes or who fail to recognize that bradycardia contradicts cocaine's mechanism. ## Clinical Pearl In Indian emergency departments, cocaine-induced acute coronary syndrome is increasingly recognized in young urban patients presenting with chest pain, diaphoresis, and normal or minimal coronary atherosclerosis on angiography. Recognition of the sympathomimetic toxidrome (tachycardia, hypertension, agitation) is critical to avoid misdiagnosis and to guide safe management—β-blockers alone are contraindicated and may worsen coronary vasospasm due to unopposed α-adrenergic effects. _Reference: Robbins Ch. 9 (Cellular Injury & Adaptation); KD Tripathi Ch. 12 (Sympathomimetic Amines); Harrison Ch. 396 (Poisoning & Drug Overdose)_