Wednesday Wrap-up: ICU Conference 3/28/2012

ICU Conference 3/28/12 Follow-Up: Serotonin Syndrome and NMS

Pt on “multiple psychiatric medications” presents to the ER “acting strangely”… after doing a physical exam and excluding other potential causes, your primary differential includes…

Serotonin Syndrome

Epidemiology: Occurs in 15% of patients who overdose on SSRI’s

Pathophys: Excess serotonergic activity due to inhibition of reuptake and metabolism of serotonin

Most common causes: SSRI’s/ SNRI’s, TCA’s, MAO-I’s, MDMA, Lithium, anti-emetics

Presentation: Clinical Triad – AMS, autonomic instability/ hyperactivity, neuromuscular rigidity. “Wet dog shakes”

Making the Diagnosis: Primarily clinical; Can also use Hunter criteria

Treatment: Benzodiazepines and cooling if necessary! Also consider: Cyproheptadine and Chlorpromazine (serotonin antagonist). Consider paralyitcs for severe cases.

NMS

Epidemiology: Typically occurs in the first month of treatment with anti-psychotics; Approximately .02% incidence in all pts on anti-psychotics. Highest risk with high doses and high potency medications and parenteral administration.

Pathophys: Dopamine antagonism

Symptoms: Altered mental status, muscle rigidity, hyperthermia, autonomic instability. Typically develop over hours to days

Treatment: Treat the hyperthermia aggressively – cooling blankets, ice packs, cooled saline, ice bath. Dantrolene (muscle relaxant), Bromocriptine, and Benzodiazepines for agitation.

Serotonin Syndrome	NMS
Hyperkinetic	Bradykinetic
Lower extremities primarily	All muscle groups involved
Clonus, Hyperreflexia	Rigidity
Excess serotonin	Dopamine antagonism
<12 hrs onset after agents	1-2 days onset

Primary treatments for both: Withdraw offending agensts, supportive care with benzodiazepines and cooling! (Always call the tox center)

References:

(You will need your Downstate library passwords to access some of these articles)

Boyer et al. The Serotonin Syndrome. NEJM 352;11. March 17, 2005.

Hoffman RJ. Chapter 41. The Critically Ill Poisoned Patient. In: Farcy DA, Flaxman A, Marshall JP, Chiu WC, eds. Critical Care Emergency Medicine. New York: McGraw-Hill; 2012.

Juurlink DN. Chapter 69. Antipsychotics. In: Hoffman RS, Nelson LS, Goldfrank LR, et al, eds. Goldfrank’s Toxicologic Emergencies. 9th ed. New York: McGraw-Hill; 2011.

Emedicine – Neuroleptic Malignant Syndrome

Emedicine – Serotonin Syndrome