Criteria

Hunter Serotonin Toxicity Criteria (HSTC)[4]

A number of clinical diagnostic criteria have been used to diagnose serotonin toxicity. The Sternbach criteria were the first suggested, but they were developed from the literature, did not include some of the most important diagnostic features (e.g., clonus), and included a number of nonspecific features.[9] This has led to a number of medications being associated with serotonin toxicity without sufficient evidence: in particular, several antipsychotic drugs.[15][19] These criteria are generally not used any more.[21]

The best diagnostic criteria, with good sensitivity (84%) and specificity (97%), are the Hunter Serotonin Toxicity Criteria (HSTC).[4] These criteria were developed from a large series of overdoses of serotonergic drugs and have now been used in a number of other studies of therapeutic drug use.[5][17] These criteria rely on a good focused neurologic exam, including assessing tone, clonus, and reflexes.

In the presence of a serotonergic agent, serotonin toxicity exists:

  • If spontaneous clonus is present OR

  • If inducible clonus AND agitation or diaphoresis are present OR

  • If ocular clonus AND agitation or diaphoresis are present OR

  • If tremor AND hyperreflexia are present OR

  • If hypertonia AND pyrexia (temperature >100.4°F [>38°C]) AND ocular clonus or inducible clonus are present.

[Figure caption and citation for the preceding image starts]: Hunter Serotonin Toxicity Criteria (HSTC) algorithmFrom the collection of Dr Geoffrey Isbister [Citation ends].com.bmj.content.model.Caption@7e4fdd5c

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