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.