Chemical Burns


Overview
The classes of burning chemicals include acids, alkalis, oxidizing agents, corrosives, reducing agents, desiccants, vesicants, protoplasmic poisons (see Table 3.14).
  • Acids cause coagulative necrosis, creating a tough eschar preventing deep penetration of burn.
  • Alkalis cause liquefactive necrosis, a poor barrier, so burns travel much deeper. For this reason, alkali burns tend to be worse than acid burns.
  • Cement contains lime, which is converted with water to the alkali calcium hydroxide.
TREATMENT
  • The first line in chemical-burn therapy is ample irrigation to remove the offending agent, except with
    • Dry powder (lime): Brush away before hydration.
    • Sodium metals: Use oil, not water.
    • Phenol (carbolic acid)
  • Be careful of heat production when chemicals react with water or their neutralizing agents.
  • Lacrimators (tear gas and pepper spray) irritate mucosa (eye, nose, and mouth) and are treated with copious water irrigation.
  • Airbag deployment utilizes an exothermic reaction that can cause burns (sodium azide) and keratitis (sodium hydroxide). These are treated with thorough irrigation with water.
Clinical Pearls
Common alkalis ("lyes") include drain and toilet cleaners, detergents, cement, and paint removers. Treat with copious irrigation

Glass etching => hydrofluoric acid burn => treat with calcium gluconate. The skin often looks normal and pain may not begin for hours after exposure.

The primary treatment for almost all chemical exposures except metals, dry powder lime, and phenol is water irrigation.

Chemical burns to the eyes are emergencies and require immediate and copious irrigation to restore ocular pH to 7.3-7.7.

Determinant of injury:
Crush - mass, deformation, yaw Cavitation - velocity, tissue elasticity

Handguns fire low-velocity bullets.

Table - Chemical Burns
  WHERE
FOUND
DAMAGE TREATMENT SPECIAL
Acids
Acetic acid Hair wave neutralizer Partial-thickness burns to scalp Water irrigation Oral abx for persistent bacteria on the scalp
Carbolic acid
(Phenol)
Industrial & medicinal Painless white/brown coagulum - may prevent penetration of water irrigation Polyethylene glycol & industrial methylated spirits or isopropyl alcohol Penetrates more deeply when dilute than when concentrated.
Chromic acid Industrial chromium plating and glass cleaning Chronic penetrating ulcerating lesions Water irrigation & surgical excision to prevent systemic toxicity High systemic toxicity following skin absorption
Formic acid Industrial & agricultural Coagulative necrosis Water Irrigation Acidosis, Hemolysis, Hemoglobinuria
Hydrochloric/ Sulfuric Acid Toilet bowl/Drain cleaners,
Battery acid
Bleach
Industrial
Dark brown or black burns Water Irrigation  
Hydrofluoric Acid High-octane fuel, etching, semiconductors rust remover Deep painful burns with possible blue-gray skin and erythema Irrigation

Calcium gluconate (topical/IM/SQ/intra-arterial)
Treat until pain is gone
Concentration effect not duration effect

Ca↓, Mg↓, K↑, myocardial instability

Pain parallels extent of injury.
Methacrylic acid Nail cosmetics Dermal burns Water Irrigation Preschoolers
Nitric acid Metal work, fertilizers Yellowish burns Water Irrigation  
Oxalic acid Leather and blueprint   Water Irrigation & IV Calcium Binds Ca, inhibits muscle contraction
Alkalis
Lyes
Ammonium
Barium
Ca, Li
KOH, NaOh
Drain cleaners, detergents, paint removers Deep burns Prolonged water irrigation Ingestion can cause airway occlusion &/or esophageal trauma
Lime (calcium oxide) Cement Exothermic rxn when neutralized with water Profuse water via strong stream to prevent burn First, brush away dry particles.
Metals Agricultural Molten metal burns Mineral oil & excision - NO water Metal can ignite when in contact with air or
water.
Hydrocarbons Gasoline and tar Fat-dissolving corrosive injury Decontamination Polysorbate to remove tar Frostbite and dehydration from skin contact
Vesicants DMSO
Cantharides
Mustard gas
Deep penetration, blisters, ulcers Water irrigation or absorbent powder Anoxic Necrosis
Alkyl mercury Disinfectant
Fugicide
Wood preservative
Erythema & Blistering Debride & Drain blisters
Water Irrigation
Blister contain mercury
White phosphorus Explosives
Insecticides
Deep & Superficial Water Irrigation
Copper Sulfate
May ignite when dry, Keep wet