In the emergency department setting, rapid identification of specific substance toxidromes is critical for guiding appropriate acute management and supportive care. Match each substance-related clinical state with its most characteristic physical examination findings and clinical presentation.
- Phencyclidine (PCP) intoxicationProminent multidirectional (horizontal and vertical) nystagmus, extreme psychomotor agitation, diminished pain perception, and autonomic instability
- MDMA (Ecstasy) intoxicationSevere bruxism, hyperthermia, tachycardia, increased sociability, and risk of life-threatening hyponatremia
- Opioid withdrawalMydriasis, rhinorrhea, excessive yawning, piloerection, and severe gastrointestinal distress (nausea, vomiting, diarrhea)
- Inhalant intoxicationBrief duration of euphoria followed by lethargy, ataxia, and a characteristic erythematous perioral or perinasal rash
Answer
Phencyclidine (PCP) intoxication matches with multidirectional nystagmus and diminished pain perception; MDMA intoxication matches with bruxism, hyperthermia, and hyponatremia; Opioid withdrawal matches with mydriasis, rhinorrhea, and piloerection; Inhalant intoxication matches with brief euphoria, lethargy, and a perioral rash.
Each substance produces a highly specific toxidrome. PCP acts as an NMDA receptor antagonist, uniquely causing multidirectional nystagmus. MDMA enhances serotonin, dopamine, and norepinephrine release, leading to sympathetic arousal, bruxism, and hyponatremia. Opioid withdrawal triggers an uninhibited locus coeruleus, causing severe sympathetic hyperactivity (mydriasis, piloerection, rhinorrhea). Inhalants act quickly as CNS depressants, and the chemical exposure directly damages perioral skin.
Step-by-Step Solution
Key Concept
Clinical recognition of specific substance intoxication and withdrawal toxidromes based on characteristic physical examination findings.
Estimated Time:1m 30s