Anticholinergic Syndrome

Summary

Anticholinergic syndrome is a clinical condition caused by excessively low levels of acetylcholine signaling, most often caused by anticholinergic medications. Clinically, anticholinergic syndrome manifests as urinary retention, dry mouth, pupil dilation, constipation, tachycardia, and altered mental status. The best antidote to treat anticholinergic syndrome is physostigmine.

Key Points

• Anticholinergic Syndrome
  • Cause
    • Decreased acetylcholine
      • Usually caused by drugs with anticholinergic properties (atropine, antipsychotics, TCAs, etc.)
  • Symptoms
    • Think reduced “rest and digest”
    • Tachycardia
    • Dry mouth
      • Caused by decreased secretions (e.g. saliva)
    • Constipation
    • Urinary retention
    • Blurry vision / Mydriasis (pupil dilation)
      • Caused by pupil dilation and cycloplegia (inhibited lens focusing)
    • Altered mental status (confusion)
      • Delirium/hallucinations and confusion may be seen in elderly patients due to reduced acetylcholine signaling in the central nervous system
      • This is the rationale for using Beer’s criteria to avoid medications in at-risk patients
  • Treatment
    • Physostigmine