Serotonin Syndrome


Background

Etiology 

Risk Factors/ Predisposition

History

Physical Examination

Diagnostic Tests

Differential Diagnosis

Treatment

  1. Discontinue offending agent
  2. ABCs, IV, O2, monitor (supportive care)
  3. Antidote (consider in selected cases)
  4. Decrease absorption
  5. Increase elimination
  6. Muscle rigidity (cause of hyperpyrexia)
  7. Seizures: benzodiazepines or barbiturates
  8. Hypertension
  9. Hypotension: norepinephrine is preferred

Follow Up

  1. ICU admission
  2. Admit other patients to the ward and manage accordingly

Prognosis

  1. Overall good prognosis
  2. May be fatal
  3. Features associated with life threatening disease include

Prevention

  1. Increasing clinician's awareness of serotonergic drugs & their side effects
  2. Avoiding combination drugs that may cause SS if possible
  3. Teaching patients about the disease & possible causes

 

Serotonin Syndrome Anti-cholinergic Syndrome Neuroleptic malignant syndrome (NMS)
Temp, HR, BP, Tachypnea Temp, HR, BP, Tachypnea Temp, HR, BP, Tachypnea
Pupils: Dilated Pupils: Dilated Pupils: Normal
Skin: Diaphoretic Skin: flushed Skin: Diaphoretic
Mucous Membrane: Drooling/ Salivation Mucous Membrane: Dry Mucous Membrane: Drooling/ Salivation
Tone in extremities, w/ hyper-reflexia & clonus Normal muscle tone  reflexes "lead-pipe" rigidity & reflexes
Treatment Treatment Treatment
Emergency/Severe:
- Midazolam 1-5mg/hr IV infusion and Morphine sulfate 1-5mg/hr IV infusion

Moderate:
- Diazepam 5-10 mg po x1, may repeat in 30-60 min
OR
- Cyproheptadine 12 mg PO x1, may repeat x1.

PLUS
Chlorpromazine 12.5-50mg IV ove 30-60 min. May repeat 4-8 hr according to response.
PLUS/Minus
Muscle paralysis (if rhabdo present)
GI symptoms:
 - Zofran + Bismuth, +/- IV Fluids

Tachycardia:
 - Lorazepam

Bradycardia:
- Atropine 0.5 mg IM/IV

Seizure:
- Lorazepam




 
Acute:
- Stop anti-psychotic meds
- IV Fluids
- Hyperthermia: Physical measures. (Tylenol, IBU do not work)
- Dysphasia: NG Tube.

Pharmacologic Therapy:
- Lorazepam 1-4 mg PO/IV x1
- Dandroline:
 Load: 2.5mg/kg IV Bolus, repeat PRN.
 Maintenance: 0.25mg/kg/hr IV infusion x36 hr.

 

Serotonin Vs Anticholinergic Syndromes VS NMS
  Skin Muscular Tone Reflexes
Serotonin syndrome Diaphoretic Increased Hyperreflexia
Anticholinergic Dry Normal Normal
Neuroleptic malignant syndrome Diaphoretic
pallor
“Lead pipe” rigid Bradyreflexia