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Zorluk: OrtaSubstance-Related and Addictive Disorders

A 20-year-old male university student is brought to the emergency department by his roommate due to severe agitation and confusion. The roommate reports that the patient has been acting increasingly bizarre over the last six hours. When questioned, the roommate admits the patient ingested multiple bottles of over-the-counter dextromethorphan-containing cough syrup earlier today in an attempt to experience hallucinations. The patient has a history of major depressive disorder, for which he takes daily fluoxetine. Vital signs show a temperature of 39.4∘C39.4^\circ\text{C} (102.9∘F102.9^\circ\text{F}), pulse of 134/min134/\text{min}, blood pressure of 172/105 mmHg172/105\text{ mmHg}, and respiratory rate of 22/min22/\text{min}. Physical examination reveals a diaphoretic, flushed young man who is disoriented to time and place. He exhibits spontaneous muscle twitching and a coarse bilateral tremor. Neurologic examination is notable for marked hyperreflexia in the lower extremities and sustained ocular clonus. In addition to providing intravenous fluids and supportive care, which of the following is the most appropriate next step in management?

  1. A
    Administer empirical intravenous ceftriaxone and vancomycin
  2. B
    Transfer the patient to radiology for a non-contrast head computed tomography scan
  3. C
    Admit the patient to the psychiatric unit for treatment of brief psychotic disorder
  4. D
    Disclose the illicit substance abuse to university law enforcement
  5. Administer cyproheptadineCevap

Cevap

Administer cyproheptadine
The correct answer is administering cyproheptadine. This patient is exhibiting classic signs of Serotonin Syndrome (SS), a potentially life-threatening condition caused by excessive serotonergic activity in the central and peripheral nervous systems. The syndrome is classically characterized by a triad of altered mental status (agitation, confusion), autonomic instability (hyperthermia, tachycardia, diaphoresis, hypertension), and neuromuscular hyperactivity (tremor, hyperreflexia, and ocular or spontaneous clonus). The patient's recreational ingestion of large amounts of dextromethorphan (an NMDA receptor antagonist that also blocks serotonin reuptake) while on a maintenance dose of fluoxetine (an SSRI) precipitated this crisis. Management of SS involves discontinuing the offending agents, providing supportive care (intravenous fluids, cooling measures), and administering benzodiazepines for agitation and tremor. If symptoms are severe or refractory, the specific antidote cyproheptadine (a 5-HT2A receptor antagonist) is indicated.

Adım Adım Çözüm

1
Identify the primary toxidrome based on clinical presentation and history.
The patient presents with autonomic instability (hyperthermia, tachycardia, hypertension), altered mental status, and neuromuscular hyperactivity (hyperreflexia, ocular clonus) following ingestion of dextromethorphan while on fluoxetine.
Recognizing the classic triad of Serotonin Syndrome is essential for distinguishing it from other causes of fever and altered mental status.
2
Determine the pharmacological mechanism causing the syndrome.
Fluoxetine is a selective serotonin reuptake inhibitor (SSRI). Dextromethorphan, commonly abused for its dissociative effects, also possesses significant serotonin reuptake inhibition properties.
The combination of multiple serotonergic agents precipitates a life-threatening excess of serotonin in the central nervous system.
3
Select the most appropriate targeted pharmacotherapy.
Cyproheptadine is chosen as the definitive antidote.
Cyproheptadine is a histamine-1 receptor antagonist with non-specific 5-HT1A and 5-HT2A antagonistic properties, directly reversing the serotonergic excess when supportive care and benzodiazepines are insufficient.

Anahtar Kavram

Serotonin syndrome can be precipitated by the combination of prescribed SSRIs and recreational substances with serotonergic activity, such as dextromethorphan. It presents with autonomic instability, altered mental status, and neuromuscular hyperactivity (e.g., clonus), and is treated with cyproheptadine.
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