Lecture Notes: Serotonin Syndrome and Neuroleptic Malignant Syndrome

Overview

• Serotonin Syndrome: Over-activation of the serotonergic system, associated with serotonergic medications.
• Neuroleptic Malignant Syndrome (NMS): Life-threatening condition linked to dopamine receptor antagonist medications.

Serotonin Syndrome

• Pathophysiology: High levels of serotonin lead to changes in mood, appetite, sleep, attention, gastrointestinal motility, thermoregulation, and platelet functioning.
• Medications Involved:
  • SSRIs (Selective Serotonin Reuptake Inhibitors)
  • MAOIs (Monoamine Oxidase Inhibitors) - highest risk
  • TCA (Tricyclic Antidepressants)
  • Combination of serotonergic medications (e.g., SSRI + TCA)
  • St. John's Wort, Linezolid, Ciprofloxacin, Dextromethorphan, Tramadol, Meperidine
• Symptoms:
  • Triad: Mental status changes, autonomic hyperactivity (fever, hypertension, tachycardia), neuromuscular abnormalities (clonus), gastrointestinal issues (diarrhea, nausea, vomiting).
• Mnemonic: MAN (Mental status changes, Autonomic hyperactivity, Neuromuscular abnormalities)

Neuroleptic Malignant Syndrome (NMS)

• Pathophysiology: Excessive dopamine or D2 receptor antagonism impacting the nigrostriatal pathway (movement), hypothalamus (temperature set point), and spinal cord.
• Medications Involved:
  • Typical antipsychotics (e.g., Haloperidol)
  • Atypical antipsychotics (e.g., Clozapine, Risperidone, Quetiapine)
  • Anti-dopaminergic antiemetics
  • Withdrawal from dopamine antagonist medications (e.g., Levodopa)
• Symptoms:
  • Fever, autonomic hyperactivity (hypertension, tachycardia), rigidity (lead pipe), mental status changes
  • Laboratory findings: Elevated creatine kinase, leukocytosis (increased white blood cell count)
• Mnemonic: FARM (Fever, Autonomic dysfunction, Rigidity, Mental status changes)

Key Differences

• Serotonin Syndrome:
  • Presence of clonus
  • Gastrointestinal symptoms (diarrhea)
• Neuroleptic Malignant Syndrome:
  • Rigidity (lead pipe)
  • Laboratory findings (elevated creatine kinase, AST, ALT, and white blood cell count)

Summary

• Serotonin syndrome and NMS share symptoms like fever, autonomic dysfunction, and mental status changes but differ in neuromuscular abnormalities and laboratory findings.
• Mnemonics help in distinguishing the conditions: MAN for serotonin syndrome and FARM for neuroleptic malignant syndrome.

---

• For more detailed lessons, refer to the full lessons on these topics. Remember to subscribe for more lessons.