SEROTONIN  SYNROME

 

Overview:

  1. The syndrome is characterized by the triad of  AMS, Autonomic dysfunction, Neuromuscular  abnormalities.
     
  2. The triad, being similar to neuroleptic malignant syndrome (NMS),  may lead to misdiagnosis.
     
  3. Serotonin syndrome is usually the result of drug interaction. Stimulation of  5-HT1 by serotonin precursors  or agonists (LSD, Lithium, L-dopa), or agents that release serotonin , like methylenedioxy-methamphetamine (MDMA= "ecstasy") and  non-specific inhibitors of  5-HT metabolism (cocaine, MAOIs) can all precipitate serotonin syndrome.
                                                                                    
  4. Many SSRIs have long  T1/2 and  S & S can occur 1-6 wk. after SSRI is discontinued if precipitating drug is  introduced.
     
  5. Most pts recover with supportive care only.

SSRI & Use:

The common SSRIs are:

Clinical uses of SSRIs:

Zoloft (Sertraline)

Bulimia

Prozac (Fluoxetine)

Depression

Paxil (Paroxetine)

Panic Disorder

Luvox (Fluvoxamine)

Headache
 

 

 

 

 

S & S :

  1. The triad c/o:                                                                
    1. Altered Mental Status that can present with any of the following:
                                                                  
      • Agitation  
      • Coma
      • Confusion
      • Delirium 
      • Hallucination
         
    2. Autonomic dysfunction that can present with  any of the following:
       
      • BP fluctuation
      • Diaphoresis
      • Diarrhea
      • Tachycardia
      • ­ temp
      • Mydriasis (pupils remain reactive)
         
    3. Neuromuscular abnormalities that can present with  any of the following:
       
      • Akathisia
      • Clonus
      • Rigidity
      • Rhabdo
      • Opistotonus
      • Hyperriflexia
      • Chorea
      • Seizures
         
  2. Laboratory  Findings:
      • Diagnosis is clinical since no confirmatory  test exists.
      • Hypermetabolic state
      • ­ WBC
      • ­ CPK
      • ¯ HCO3
      • QRS/QT prolongation has been reported with some SSRIs. It is unknown if the are associated with  serious adverse effects and so far no treatments are advocated except for  observation

Differential   DX:

  1. The BIG in differential is NMS. Several authors suggested  looking  for  lead-pipe rigidity and the absence of  mydriasis, both favoring NMS.
     
  2. Others in a differential are: Catatonia, Dystonia, Encephalitis, Hyperthyroidism, Tetanus,  Anticholinergics, Cocaine, Amphetamine, LSD, PCP, Strychnine

Management:

  • Mild and moderate cases usually resolve in 24-72 hrs.
    1. Supportive care. This consists of:
       
        •  cooling
        • sedatives
        • mechanical ventilation prn
        • anticonvulsants
           
    2. 5-HT antagonists such as chlorpromazine ,  cyproheptadine,  methysergide and propranolol   may be effective.

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