Serotonin syndrome
Background
Serotonin works centrally to modulate attention, behavior, thermoregulation
dx when serotinergic agent/ SSRI recently added to med list
Offending Agents:
SSRIs
MAOIs
TCAs
Drugs of Abuse: Cocaine, Ecstasy, Marijuana
Analgesics: demerol, fentanyl
Antiemetics
OTC: Cough meds, herbal products, St John’s Wort
Triptans
Bromocriptine
Diagnosis
Clinical Triad:
1) Altered Mental Status: Agitated delirium
2) Autonomic Instability: Hyperthermia, Tachycardia
3) Neuromuscular Abnormalities: Clonus, hyperreflexia
Physical Exam
Clonus is most defining feature: Spontaneous or inducible
Ocular clonus (horizontal)
Shivering
Hyperreflexia
Diaphoresis
Nausea
Diagnostic Criteria
Hunter Criteria Decision Rules
(84% Sensitivity; 97% Specificity)
Serotonergic Agent plus 1 of following:
Spontaneous Clonus
Inducible Clonus plus Agitation
Ocular Clonus plus Agitation
Clonus plus Hyperthermia
OR
need 3 of 6
- mental status change
- agitation
- myoclonus
- hyperreflexia
- diaphoresis
- shivering
- tremor
- diarrhea
- incoordination
- fever
Treatment
ABCs
Discontinue offending agent
Supportive Care
Benzos for agitation
Avoid physical restraints
Consider paralysis with non-depolarizing agent
Cyproheptadine
serotonin antagonist (works centrally and peripherally)
An animal model showed that an initial dose (12mg) blocked 85-95% of serotonin receptors
Dose: 8mg PO/NG, then 4mg Q2H;
Max 32mg/day
Clinical Course
Serotonin Syndrome generally presents within 6-24H of exposure to offending agent Resolves within 24H
Mortality < 1%
Source
PANI 6/2009 based on Rosen's