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?
- Acute?
-
- Chronic?
- Index of suspicion
- Trigger?
- Chronic?
- Lab Studies
- Digoxin Level
- 6 hour level
- Earlier levels don’t reflect steady state
- Potassium
- Marker of acute toxicity
- Prognostic value
- Digoxin Level
- 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
- Bowel decontamination
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
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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