Hydrofluoric acid (HF)

Background

• Hydrofluoric acid (HF) is found in industrial cleaning agent for metals / glass or in household rust removing agents
• HF is an extremely caustic inorganic acid

Pathophysiology

• Fluoride ion penetrates skin and permeates deep tissues (incl. bone)
• Fluoride binds calcium forming insoluble salts
• ↓↓Ca⁺⁺ in local tissues → cell necrosis
• Local tissue death → local K⁺release irritating nerve endings = pain ++

Clinical

• HF burns may present early (severe pain, HF conc. usually >20%) or late
• Typically, very intense (± delayed) pain
• Systemic toxicity due to ↓Ca⁺⁺, ↓Mg⁺⁺, ↑K⁺ → arrhythmia

Management

1. Manage systemic toxicity
2. Local pain control
3. Prevention of progressive tissue damage

Systemic toxicity

• IV calcium gluconate

Local toxicity / burn

• Wash (repeatedly) with Diphoterine (cylinder in decontamination room in CUH ED)
• Topical calcium gluconate
• Local Ca⁺⁺ gluconate infiltration
• "Biers block"
  • 10-20 ml Ca⁺⁺ gluconate diluted to 40ml
  • Leave cuff inflated for 15 minutes
  • Early release of cuff may cause flushing, headache & arrhythmia
• Intra-arterial Ca⁺⁺ gluconate

Links

• Diphoterine brochure