Serotonin syndrome
Background
- Can be produced by any serotonergic medication
- Vast majority of cases occur with therapeutic dosages
- Most common cause of death is severe hyperthermia
Causative Agents
- SSRIs
- MAOIs
- TCAs
- Drugs of Abuse: Cocaine, Ecstasy, Marijuana
- Analgesics: Demerol, fentanyl
- Antiemetics
- Triptans
- Bromocriptine
- OTC: Cough meds like Dextromethorphan, herbal products, St John’s Wort
Clinical Features
- Altered mental status: Agitated delirium
- Autonomic Instability: Hyperthermia, Tachycardia, hypertension, diaphoresis [1]
- Often labile blood pressure, HR
- Neuromuscular Abnormalities: Myoclonus, ocular clonus, rigidity, hyperreflexia, tremor
- More pronounced in the lower extremities
- Myoclonus: most common finding
- Important to identify because it does not occur in other conditions that mimic serotonin syndrome
Differential Diagnosis
Altered mental status and fever
- Infectious
- Sepsis
- Meningitis
- Encephalitis
- Cerebral malaria
- Brain abscess
- Other
Diagnosis
Hunter Toxicity Criteria Decision Rules
Serotonergic agent plus 1 of the following[2]:
- Spontaneous clonus
- Inducible clonus AND (agitation or diaphoresis)
- Ocular Clonus AND (agitation or diaphoresis)
- Tremor AND hyperreflexia
- Hypertonia AND temp >38 AND (ocular clonus or inducible clonus)
84% Sn, 97% Sp
Management
- Discontinue all serotonergic drugs
- Aggressive supportive care
- If pressors required, direct acting (e.g. norepi, epi) preferred, MAO inhibition causes erratic response to dopamine
- Benzos
- Goal is to eliminate agitation, neuromuscular abnormalities, elevations in HR/BP
- Cyproheptadine[3]
- Give if benzos and supportive care fail to improve agitation and abnormal vitals
- Serotonin antagonist
- Give 12mg PO/NG; repeat with 2mg q2hr until clinical response is seen (max 32mg/d)
- Give 4mg q6hr x48hr if pt is responsive to initial dose
- Chlorpromazine[4]
- Phenothiazine with antiserotonergic effects
- 50mg to 100mg IM
- Can consider in severe cases
- Dexmedetomidine[5]
- Small case series found this helpful in adolescent cases refractory to benzos
- Treat hyperthermia
- Hyperthermia due to increase in muscular activity, not change in set point
- Intubate and paralyze if temp > 41.1
- Standard cooling measures
Disposition
See Also
References
- ↑ Boyer, E. W. and Shannon, M. (2005) ‘The Serotonin Syndrome’, New England Journal of Medicine, 352(11), pp. 1112–1120. doi: 10.1056/nejmra041867
- ↑ Dunkley EJ, Isbister GK, Sibbritt D, Dawson AH, Whyte IM. The Hunter Serotonin Toxicity Criteria: simple and accurate diagnostic decision rules for serotonin toxicity. QJM 2003;96:635-642
- ↑ Graudins, A., Stearman, A. and Chan, B. (1998) ‘Treatment of the serotonin syndrome with cyproheptadine’, The Journal of Emergency Medicine, 16(4), pp. 615–619. doi: 10.1016/s0736-4679(98)00057-2
- ↑ Gillman PK. The serotonin syndrome and its treatment. J Psychopharmacol 1999;13:100-109
- ↑ Rushton WF, Charlton NP. Dexmedetomidine in the treatment of serotonin syndrome. Ann Pharmacother. 2014; 48(12):1651-1654.