Clinical Assessment

Assessment requires a careful history to elicit any history of ingestion of possible causative agents and examination looking for features outlined previously.


Key features to look for include:

  • Cerebral agitation
  • Pupil size and eye movements
  • Limb movements
  • Muscle movements (induced or constant)
  • Muscle tone
  • Skin signs (sweating, dry, warm)
  • Mucous membrane (moist, dry)
  • Cardiovascular features (tachycardia, hypertension)
  • Other features (fitting, urinary retention)

Features suggesting other causes:

  • Obvious source of symptoms of infection (sepsis)
  • Signs of thyrotoxicosis

Hunter serotonin toxicity criteriea

Some decision tools exist to help diagnose less common conditions against certain diagnostic criteria such as the Hunter Serotonin Toxicity Criteria [8]:

Hunter serotonin toxicity criteriea: decison rules
In the presence of a serotonergic agent:
1 IF (spontaneous clonus = yes) THEN serotonin toxicity = YES
2 ELSE IF (inducible clonus = yes) AND [(agitation = yes) OR (diaphoresis = yes)] THEN serotonin toxicity = YES
3 ELSE IF (ocular clonus = yes) AND [(agitation = yes) OR (diaphoresis = yes)] THEN serotonin toxicity = YES
4 ELSE IF (tremor = yes) AND (hyperreflexia = yes) THEN serotonin toxicity = YES
5 ELSE IF (hypertonic = yes) AND (temperature > 38ºC) AND [(ocular clonus = yes) OR (inducible clonus = yes)] then serotonin toxicity = YES
6 ELSE serotonin toxicity = NO

Learning bite

The symptoms associated with the drug induced hyperthermia syndromes are very similar. Details of the medication history might point towards the diagnosis. Differential diagnoses of the symptoms such as infection and thyrotoxicosis also need to be considered before assuming the symptoms are due to a drug induced hyperthermia syndrome.

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