What is the difference between Extrapyramidal Symptoms (EPS) and Tardive Dyskinesia?

Extrapyramidal Symptoms vs. Tardive Dyskinesia: Key Differences

Extrapyramidal symptoms (EPS) are acute movement disorders that occur during antipsychotic treatment, while tardive dyskinesia (TD) is a chronic involuntary movement disorder that typically develops after prolonged antipsychotic use and may persist even after medication discontinuation. 1

Extrapyramidal Symptoms (EPS)

EPS refers to a group of acute movement disorders that occur as side effects of antipsychotic medications, typically appearing shortly after starting treatment or increasing dosage:

• Types of EPS:

  • Acute dystonia: Involuntary muscle contractions causing abnormal postures or movements
  • Drug-induced parkinsonism: Rigidity, tremor, bradykinesia
  • Akathisia: Subjective feeling of restlessness with compelling need to move
  • Akinesia: Reduced spontaneous movement

• Key characteristics:

  • Appear early in treatment (hours to weeks)
  • Often respond to anticholinergic medications
  • Usually reversible when medication is reduced or discontinued
  • Primarily caused by dopamine blockade in the basal ganglia 2

Tardive Dyskinesia (TD)

TD is characterized by involuntary, repetitive movements that typically develop after prolonged exposure to antipsychotics:

• Key characteristics:
  • Presentation: Athetoid or choreiform movements, primarily in the orofacial region (lip smacking, tongue protrusion, facial grimacing), but can affect any body part 1
  • Timing: "Tardive" means late-appearing - typically develops after months or years of antipsychotic use
  • Persistence: May persist or even worsen after discontinuation of the causative medication
  • Treatment resistance: Often does not respond to anticholinergic medications (may worsen with them) 1
  • Treatment options: VMAT2 inhibitors like valbenazine may be effective 1, 3

Critical Distinctions

1. Timing:

   • EPS: Acute onset (hours to weeks after starting medication)
   • TD: Delayed onset (months to years of treatment)

2. Reversibility:

   • EPS: Usually reversible when medication is adjusted or discontinued
   • TD: Often persistent even after medication discontinuation

3. Response to anticholinergics:

   • EPS: Often improves with anticholinergic medications
   • TD: May worsen with anticholinergic medications 1

4. Movement characteristics:

   • EPS: Includes rigidity, tremor, restlessness
   • TD: Characterized by choreiform/athetoid movements, particularly in orofacial region

5. Pathophysiology:

   • EPS: Primarily due to acute dopamine blockade
   • TD: Thought to involve dopamine receptor supersensitivity after prolonged blockade 4, 5

Management Considerations

• For EPS:

  • Reduce antipsychotic dose if possible
  • Consider anticholinergics (benztropine 1-2 mg daily) for acute symptoms
  • Beta-blockers may help for akathisia 1

• For TD:

  • Prevention is critical - use minimum effective doses of antipsychotics
  • Regular monitoring with standardized scales (AIMS every 3-6 months)
  • Consider VMAT2 inhibitors (valbenazine) for established TD 1, 3
  • Avoid anticholinergics as they may worsen TD 1

Clinical Pitfalls

• Akathisia can be misdiagnosed as anxiety or agitation 6
• Anticholinergics may help EPS but worsen TD 1
• Parkinsonism from antipsychotics can be mistaken for primary Parkinson's disease 2
• Up to 50% of elderly patients may develop TD after 2 years of typical antipsychotic use 1
• Neuroleptic Malignant Syndrome is a rare but potentially fatal complication that requires immediate discontinuation of the antipsychotic 3

Understanding these distinctions is crucial for proper diagnosis and management of movement disorders in patients taking antipsychotic medications.