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Difficulty: HardSubstance-Related and Addictive Disorders

A metropolitan toxicology service is evaluating several patients with suspected substance use disorders. Correlate the following distinct clinical manifestations with their correct underlying etiology.

  • Rotatory nystagmus, impulsivity, ataxia, and diminished pain perception resulting in combative behavior.Phencyclidine (PCP) intoxication
  • Severe dysphoria, vivid and unpleasant dreams, hypersomnolence, increased appetite, and psychomotor retardation.Cocaine withdrawal
  • Diaphoresis, bruxism, hyperthermia, and confusion complicated by new-onset generalized seizures and hyponatremia.MDMA (Ecstasy) intoxication
  • Mydriasis, piloerection, rhinorrhea, excessive yawning, and diffuse myalgias in an alert and highly distressed patient.Opioid withdrawal
  • Global confusion, prominent visual hallucinations, resting tremor, and autonomic hyperactivity peaking on hospital day 3.Severe alcohol withdrawal

Answer

Phencyclidine (PCP) intoxication matches rotatory nystagmus and combativeness. Cocaine withdrawal matches hypersomnolence, hyperphagia, and vivid dreams. MDMA intoxication matches bruxism, hyperthermia, and hyponatremia. Opioid withdrawal matches piloerection, yawning, and myalgias. Severe alcohol withdrawal matches day 3 delirium and autonomic hyperactivity.
Each substance toxidrome has distinct hallmark features. PCP involves nystagmus and analgesia; cocaine withdrawal involves a depressive 'crash' with hyperphagia and hypersomnolence; MDMA toxicity uniquely causes bruxism and SIADH leading to hyponatremia; opioid withdrawal presents with yawning, piloerection, and myalgias with an intact sensorium; and severe alcohol withdrawal (delirium tremens) features late-onset confusion, hallucinations, and autonomic hyperactivity.

Step-by-Step Solution

1
Analyze the first clinical presentation.
Rotatory nystagmus and analgesia are identified.
These are the hallmark pathognomonic signs of PCP intoxication, distinguishing it from other hallucinogens and stimulants.
2
Analyze the second presentation focusing on behavioral and sleep changes.
The combination of hypersomnolence, increased appetite, and vivid dreams is recognized as a 'crash' state.
This is characteristic of stimulant (e.g., cocaine) withdrawal, which causes neuro-depressive symptoms without significant physical autonomic signs.
3
Evaluate the third presentation noting the specific complications.
Bruxism, hyperthermia, and hyponatremia-induced seizures point directly to MDMA.
MDMA increases serotonin, dopamine, and norepinephrine, and uniquely triggers ADH release leading to severe dilutional hyponatremia.
4
Assess the fourth presentation for classic withdrawal signs.
Piloerection, mydriasis, and yawning in an alert patient indicate opioid withdrawal.
Opioid withdrawal mimics a severe viral prodrome with sympathetic overactivity but crucially does not cause delirium or altered mental status.
5
Review the timeline and symptoms of the fifth presentation.
Delirium and visual hallucinations peaking at 72 hours indicate delirium tremens.
The severe alcohol withdrawal timeline perfectly aligns with these late-stage, life-threatening autonomic and psychotic symptoms.

Key Concept

Differentiation of substance-induced toxidromes and withdrawal syndromes based on unique physical exam findings, such as nystagmus in PCP, hyponatremia in MDMA, and piloerection in opioid withdrawal.
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Topics

Substance-Related and Addictive Disorders

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