Caustic burns

Background

Caustics

• Substances that cause damage on contact with body surfaces
• Degree of injury determined by pH, concentration, volume, duration of contact
• Acidic agents cause coagulative necrosis
• Alkaline agents cause liquefactive necrosis (considered more damaging to most tissues)
• Corrosive agents have reducing, oxidising, denaturing or defatting potential

Alkalis

• Accepts protons → free hydroxide ion, which easily penetrates tissue → cellular destruction
  • Liquefactive necrosis and protein disruption may allow for deep penetration into surrounding tissues
• Examples
  • Sodium hydroxide (NaOH), potassium hydroxide (KOH), ammonia (NH3)
  • Found in: bleach, drain openers, oven cleaners, toilet cleaner, hair relaxers

Acids

• Proton donor → free hydrogen ion → cell death and eschar formation, which limits deeper involvement
  • However, due to pylorospasm and pooling of acid, high-grade gastric injuries are common
    • Mortality rate is higher compared to strong alkali ingestions
• Can be systemically absorbed and → metabolic acidosis, hemolysis, AKI
• Examples
  • Hydrochloric acid (HCl), hydrofluoric acid (HF), Sulfuric acid (H2SO4)
  • Found in: auto batteries, drain openers, metal cleaners, swimming pool products, rust remover, nail primer

Clinical Features

• Signs and symptoms are inadequate to predict presence or severity of injury after caustic ingestion
• Exam eyes and skin (splash and dribble injuries may easily be missed)
• GI tract injury
  • Dysphagia, odynophagia, epigastric pain, vomiting
• Laryngotracheal injury
  • Dysphonia, stridor, respiratory distress
  • Occurs via aspiration of caustic or vomitus or inhalation of acidic fumes

Differential Diagnosis

Caustic Burns

• Caustic ingestion
• Caustic eye exposure (Caustic keratoconjunctivitis)
• Caustic dermal burn
• Airbag-related burns
• Hydrofluoric acid
• Tar burn
• Cement burn

Evaluation

• Clinical diagnosis

Work-up

Only necessary in patients with significant injury or volume of ingestion

Consider:

• CBC
• Metabolic panel
• Lactate
• Calcium level (if Hydrofluoric acid exposure)
• ECG
  • May show QT-prolongation if hypocalcemic secondary to Hydrofluoric acid
• APAP/ASA levels if concerned about coingestion (suicidal patients)

Management

• First prevent personal exposure to the caustic agent by removing all clothing and decontaminating the patient
• Brush any dry chemicals off the patient
• Irrigate all wounds and areas of exposure with copious amounts of water
  • Exception: dry lime, phenol, metals such as potassium and sodium, causes harmful exothermic reaction

Acidic injuries (except Hydrofluoric acid)

• May also have non-anion gap acidosis (e.g. HCl)
• Respond well to copious saline or water irrigation

Alkali injuries

• May appear superficial but often are deeper with ongoing burn
• Treat with copious irrigation and local wound debridement to remove residual compound

Disposition

• Admit the following:
  • Injuries that cross flexor or extensor surfaces
  • Facial injuries
  • Perineum injuries
  • Partial-thickness injuries >10-15% of BSA
  • All full-thickness burns

See Also

• Burns

References

Authors

Ross Donaldson, Michael Holtz