Clinical Features
Diagnosis
Clinical
On physical exam, the sufferer of 5-HT toxicity may appear uncomfortable and twitchy.
Deep tendon reflexes may be very brisk.
Try to elicit clonus by flexing the patient’s foot and watching for rhythmic contractions of the ankle.
Assess for ataxia through observation of gait, Romberg testing, and point-to-point testing.
Hunter Serotonin Toxicity Criteria
In presence of serotonergic medication:
1. Spontaneous clonus? Yes = serotonin toxicity
2. Inducible clonus + agitation? [OR] inducible clonus + diaphoresis? Yes = serotonin toxicity
3. Ocular clonus + agitation? [OR] ocular clonus + diaphoresis? Yes = serotonin toxicity
4. Tremor + hyperreflexia? Yes = serotonin toxicity
5. Hypertonia + hyperthermia [>38 ℃] + ocular/inducible clonus? Yes = serotonin toxicity
6. None of the above = no serotonin toxicity
Treatment
- Stop offending agent(s)
- Aggressive temperature management
- Consider medications with anti-serotonergic activity: cyproheptadine (Periactin) or the antipsychotic chlorpromazine (Thorazine).