Serotonin syndrome is caused by the excess of serotonin and presents classically as:
- Altered mental status
- Autonomic instability
- Neuromuscular hyperactivity
Fortunately, there’s a nice algorithm (Hunter’s decision rule) which helps you decide whether it is serotonin syndrome or not. I also include a table, which I adapted from a New England Journal of Medicine review article, which helps you to differentiate it from its mimickers, such as anticholinergic syndrome, neuroleptic malignant syndrome, and malignant hyperthermia.
PV Card: Serotonin Syndrome
Adapted from [1, 2] Go to ALiEM (PV) Cards for more resources.
A video to remind you what clonus looks like:
Thanks to Dr. Steve MacDade (Univ of Florida, Jacksonville EM resident) for the idea!