Examkin

Question

Difficulty: EasySubstance-Related and Addictive Disorders

An emergency department physician is evaluating four patients who were brought in overnight with suspected substance intoxication. Match each patient's predominant physical examination findings to the most likely intoxicating substance.

  • Somnolence, pinpoint pupils, and a respiratory rate of 6 breaths/minuteOpioid
  • Tachycardia, prominent conjunctival injection, and increased appetiteCannabis
  • Combativeness, multidirectional nystagmus, and reduced perception of painPhencyclidine (PCP)
  • Psychomotor agitation, dilated pupils, and acute substernal chest painCocaine

Answer

Somnolence/miosis matches Opioid; Conjunctival injection/appetite matches Cannabis; Nystagmus/combativeness matches Phencyclidine (PCP); Agitation/chest pain matches Cocaine.
Each substance produces a specific clinical toxidrome based on its unique receptor pharmacology. Opioids stimulate mu receptors causing miosis and respiratory depression. Cannabinoid receptor activation leads to conjunctival injection. PCP acts as an NMDA receptor antagonist causing nystagmus and dissociative anesthesia. Cocaine blocks monoamine reuptake, resulting in sympathomimetic excess and vasoconstriction.

Step-by-Step Solution

1
Analyze the first patient's presentation of somnolence, pinpoint pupils, and hypoventilation.
Matches opioid intoxication.
These findings represent the classic opioid toxidrome.
2
Analyze the second patient's presentation of red eyes, rapid heart rate, and hunger.
Matches cannabis intoxication.
Conjunctival injection is a highly specific physical finding for acute cannabis use in this context.
3
Analyze the third patient's presentation of combativeness, nystagmus, and lack of pain.
Matches phencyclidine (PCP) intoxication.
Multidirectional or rotary nystagmus in an agitated patient is the hallmark of PCP toxicity.
4
Analyze the fourth patient's presentation of agitation, dilated pupils, and chest pain.
Matches cocaine intoxication.
Sympathomimetic excess combined with myocardial ischemia strongly points to cocaine.

Key Concept

Substance-Related and Addictive Disorders
Rate this question

Topics

Substance-Related and Addictive Disorders

More questions from this topic