5.3 Differential diagnosis
Relevant differential diagnoses for serotonin syndrome includes neuroleptic malignant syndrome, anticholinergic toxicity, serotonergic discontinuation syndrome, sympathomimetic drug intoxication, malignant hyperthermia, meningitis and encephalitis 16.
Neuroleptic malignant syndrome, a life-threatening neurological disorder most often caused by an adverse reaction to antipsychotic drugs24, may be confused with serotonin syndrome, especially in patients taking multiple psychiatric drugs. Neuroleptic malignant syndrome progresses more slowly and is associated with rigidity, but not hyperreflexia or clonus, compared to serotonin syndrome 4,8,11,16. As shown in table 44,8,11, clinical features, drug usage and time course provides useful information for distinguishing between the syndromes.