Toxin

Hydrofluoric Acid Toxicity

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Hydrofluoric Acid Toxicity, Hydrofluoric Acid Poisoning, Hydrofluoric Acid, Hydrofluoric Acid Antidote

  • Background
  1. Hydrofluoric Acid Industrial Uses
    1. Electroplating
    2. Glass Etching
    3. Rust Removal
    4. Brick Cleaning
    5. Semiconductor Manufacturing
  2. Mechanism of Injury
    1. Skin contact injury results in both local Burn Injury from Hydrogen Ions
    2. Systemic effects occur due to fluoride ion movement from weak surface acids to deep spaces (subcutaneous fat, vessels, nerves)
      1. Results in liquefaction necrosis
      2. Myocardial toxicity via increased cAMP (risk of refractory Ventricular Fibrillation)
    3. Fluoride chelates Calcium and Magnesium
      1. Results in Hypocalcemia and Hypomagnesemia
    4. Other Electrolyte abnormalities
      1. Hyperkalemia
  • Symptoms
  1. Onset of symptoms within hours to 24 hours after exposure
  2. Local vasospasm (pallor)
  3. Pain out of proportion
  • Signs
  1. Cardiovascular
    1. Cardiac Arrhythmia
    2. Hypotension
  2. Neurologic
    1. Confusion
    2. Cerebral edema
    3. Tetany
    4. Seizures
    5. Paresis
  • Grading
  • Indications of Significant Hydrofluoric Acid Exposure
  1. Hydrofluoric Acid concentration >50% and burn of any size
  2. Hydrofluoric Acid burn affecting >5% Body Surface Area (BSA)
  3. Hydrofluoric Acid injury to the eyes, face, genitalia or mucosa
  4. Ingestion of Hydrofluoric Acid
  5. Inhalation Injury associated with Hydrofluoric Acid
  • Labs
  1. Basic Metabolic Panel
    1. Hypocalcemia
    2. Hyperkalemia
    3. Acute Kidney Injury
  2. Serum Magnesium and Serum Phosphorus
    1. Hypomagnesemia
  3. Suspected myocardial injury
    1. Serum Troponin
    2. N-Terminal BNP
  • Diagnostics
  1. Electrocardiogram (EKG) Findings of HFA-related Myocardial Effects (esp. Electrolyte abnormalities)
    1. Prolonged QRS interval
    2. Prolonged PR Interval (first degree AV Block)
    3. QTc Prolongation
    4. T Wave Inversion or Peaked T Waves
    5. ST Segment Elevation or depression
  • Management
  1. General
    1. Personal Protective Equipment for all with patient contact
    2. ABC Management and evaluate for hemodynamic stability
    3. Early Consultation with poison control
    4. Burn Center coordination for any significant Burn Injury
  2. Decontamination
    1. Remove all clothing
    2. Copious Irrigation of contaminated regions
      1. Use saline or water for continuous 20 minute flush of burn area
      2. Saline and water have equivalent efficacy to chelating agents
  3. Antidote
    1. Topical Calcium Gluconate 2.5% gel
      1. Preprepared or mix 1 gram of 10% Calcium Gluconate IV solution in lubricant jelly
      2. Apply to all areas of Burn Injury to neutralize acid
      3. Calcium Gluconate in contact with Hydrofluoric Acid will form white Calcium fluoride crystals
      4. Replace the topical solution or gel every 15-30 minutes (after it has turned to a white color)
      5. Hand burns may be inserted into a Calcium Gluconate filled HFA-resistant glove
      6. Expect pain relief after serial applications of Calcium Gluconate (except in severe deep burns)
    2. Advanced measures for severe refractory cases
      1. Parenteral Calcium Gluconate (controversial)
        1. Subcutaneous into affected region
        2. Intravenously via regional block at affected area
        3. Distal arterial injection (e.g. radial artery, dorsalis pedis artery)
      2. Burn Center or Surgical Interventions
        1. Vasodilator infusion (e.g. alprostadil)
        2. Escharotomy
  4. Monitoring of severe exposure
    1. Vital Signs for hemodynamic instability
    2. Telemetry and serial EKG as needed
    3. Electrolyte abnormalities
    4. Renal dysfunction
      1. Hemodialysis may be needed in severe Poisonings for Renal Failure (not for HFA removal)
  • Complications
  1. Congestive Heart Failure
  2. Chronic Kidney Disease
  3. Fluoride-induced osteolysis
  • References
  1. Kinker and Glauser (2021) Crit Dec Emerg Med 35(9): 19-27