Thanks to Dr. Freedman for today’s Morning Report!

 

Digoxin Toxicity

Background:

  • Naturally occurring chemical compounds
  • Na+/ATPase Channel blockers
  • Prone to poisoning
    • Large volume of distribution
    • Long half-life, ~36 hours
    • Narrow therapeutic window, 0.6 – 1.3 ng/mL

Digoxin:

  • An Old Drug: CHF, A fib
    • ~2% of all international patients.
    • One of the 50 most commonly prescribed in U.S.
    • 1,601 acute ingestions in U.S. in 2011
    • In U.S., 1% of outpatients and ~18% of NH patients will develop toxicity
    • 0.4% of all U.S hospital admissions

Plant Cardiac Glycosides:

  • Many different flowering plants
    • Foxglove, oleander, lily of the valley et al.
  • 2.6% of all toxic plant exposures
  • 1,336 in U.S. in 2011

 

Acute Ingestions

Epidemiology: the young (one pill kill)

  • Adults: LD50 10mg
  • Pediatrics: LD 50 0.3mgkg

Presentation: Cardiac symptoms

  • Bradycardia +/- hypotension
  • Dysrhythmias
    • Sinus
    • Junctional
    • AV block
    • Slow a fib/flutter
    • Bidirectional V tach

 

Chronic Toxicity

Epidemiology: Elderly, chronically ill

  • Normal or sub-therapeutic levels
  • Triggered by:
    • Electrolyte disturbance
    • Hypovolemia
    • Drug-drug interactions

Presentation: Often non-specific

  • Altered mental status, weakness, fatigue
  • Nausea/vomiting, abdominal pain
  • Visual complaints

ECG findings:

  • “Scooped” ST segment, Digitalis Effect
  • Any of the acute dysrhythmias

 

ED Management

  • ABCs
    • Supportive care
    • Correction of electrolyte disturbance
  • H+P
    • Acute?
      • When, how much?
    • Chronic?
      • Index of suspicion
      • Trigger?
  • Lab Studies
    • Digoxin Level
      • 6 hour level
      • Earlier levels don’t reflect steady state
    • Potassium
      • Marker of acute toxicity
      • Prognostic value
  • Interventions
    • Bowel decontamination
      • Consider if <1-2 hours
    • Atropine
      • Not contra-indicated….
    • Pacing
      • Not recommended
    • Dialysis
      • Not plausible
    • Digi-Fab
      • Ingestion of 10 mg in adults, or 0.3 mg/kg in children
      • Acute ingestion with steady-state level > 10ng/mL
      • Chronic ingestion with steady-state level > 6ng/mL
      • Any dysrhythmia, irrespective of level
      • Serum potassium > 5.5 in acute ingestion
      • Any plant toxicity

Emergency Medicine Mythology:

Intravenous calcium is contraindicated in digoxin toxicity. “Stone Heart” Syndrome. Based on case studies. No data to support theory. Weak data exist to suggest calcium is safe in dig-toxic. Bottom-line: Give IV calcium if you suspect hyperkalemia.

 

Bidirectional V tach

mr07292014p1

 

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Jay Khadpe MD

  • Editor in Chief of "The Original Kings of County"
  • Assistant Professor of Emergency Medicine
  • Assistant Residency Director
  • SUNY Downstate / Kings County Hospital

Latest posts by Jay Khadpe MD (see all)


Jay Khadpe MD

  • Editor in Chief of “The Original Kings of County”
  • Assistant Professor of Emergency Medicine
  • Assistant Residency Director
  • SUNY Downstate / Kings County Hospital

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