Serotonin syndrome

Hunter criteria

• Must have a serotonergic exposure

graph TD;

spont["spontaneous clonus"] --Y--> ss["serotonin syndrome"]
spont --N--> ind["inducible clonus &<br/>agitation or diaphoresis"]
ind --Y--> ss
ind --N--> oc["ocular clonus &<br/>agitation or diaphoresis"]
oc --Y--> ss
oc --N--> trem["tremor & hyperreflexia"]
trem --Y--> ss
trem --N--> hyper["hypertonic & temp >38C &<br/>ocular clonus or inducible clonus"]
hyper --Y--> ss
hyper --N--> nss["not serotonin syndrome"]

• 84% sensitive and 97% specific

Clinical Presentation

• Fever, rigidity, clonus, diaphoresis, tremor, and agitation
• Compared to NMS, SS is more likely to have:
  • Acute onset
  • Sialorrhea, hyperactive bowel sounds
  • Hyperreflexia and clonus
  • Mydriasis

Management

• Stop all serotonergic drugs
• Supportive therapy
  • Aggressive cooling
• Sometimes can use
  • Cyproheptadine but is PO and takes 24-48h
  • Olanzapine 10mg IV BID