UMEM Educational Pearls

Category: Neurology

Title: Serotonin Syndrome (Part 1) - What is It?

Keywords: serotonin syndrome, SSRI, autonomic hyperactivity, hyperreflexia, clonus, Hunter Criteria (PubMed Search)

Posted: 9/9/2015 by WanTsu Wendy Chang, MD
Click here to contact WanTsu Wendy Chang, MD

 

Serotonin Syndrome - What is It?

  • Potentially life-threatening condition associated with increased serotonergic activity in the CNS.
  • Selective serotonin reuptake inhibitors (SSRIs) are the most commonly implicated class of medications.  However, other medications can also be involved.
  • It is a clinical diagnosis!
  • Classic triad: mental status change, autonomic hyperactivity, and neuromuscular abnormalities
    • Mental status change - anxiety, agitation, restlessness, disorientation
    • Autonomic hyperactivity - diaphoresis, tachycardia, hypertension, hyperthermia, nausea, vomiting, diarrhea
    • Neuromuscular abnormalities - tremor, muscle rigidity, myoclonus, hyperreflexia, clonus, Babinski sign (abnormal plantar reflex)
  • Hunter Criteria is the most accurate diagnostic rule:
    • Serotonergic agent + one of the following:
      • Spontaneous clonus
      • Inducible clonus + agitation or diaphoresis
      • Ocular clonus + agitation or diaphoresis
      • Tremor + hyperreflexia
      • Hypertonia + temperature above 38C + ocular clonus or inducible clonus
  • Majority of cases present within 24 hours, most within 6 hours, of a change in dose or initiation of a medication.

 

** Stay tuned for part 2 on what causes serotonin syndrome **

 

References

  • Boyer EW, Shannon M. The serotonin syndrome. N Engl J Med. 2005;352:1112-1120.
  • 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(9):635.

 

Follow me on Twitter @EM_NCC