Caustic ingestion

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)
    • Lye present in drain cleaners, hair relaxers, grease remover
  • Bleach (sodium hypochlorite) and Ammonia (NH3)
    • Cleaning products such as oven cleaners, swimming pool chlorinator
    • Household bleach ingestion (4-6% sodium hypochlorite) rarely causes significant esophageal injury

Acids

• Proton donor → free hydrogen ion → cell death via denatured protein → coagulation necrosis 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), Phosphoric acid, Oxalic Acid, Acetic acid
    • Found in: auto batteries, drain openers, toilet bowl, metal cleaners, swimming pool cleaners, rust remover, nail primer

Clinical Features

• All pts w/ serious esophageal injuries have some initial sign or symptom
  • E.g. stridor, drooling, vomiting
• 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

Diagnosis

Labs

Only necessary in patients with significant injury or volume of ingestion

• CBC
• Chemistry
• Lactic Acid
• ECG
• Calcium level (if Hydrofluoric Acid exposure)
• Acetaminophen and Salicylate levels (in pts with concern for intentional ingestion)

Imaging

• 3-View CXR CXR
  • Look for free air under the diaphragm or signs of mediastinal air
• CT
  • Consider when perforated viscus is suspected but CXR is negative
• Button battery XR - two rings, will likely need to remove it no matter where it is, whether post-pyloric or pre-pyloric

Treatment

• Prevent provider and continued patient exposure to the caustic agent by removing all clothing and decontaminating the patient

Airway Management

• Monitor closely for stridor, airway edema, hoarseness, or other signs of airway injury
• Intubate early if signs of airway injury exist, before airway becomes more difficult to manage.
• Consider awake fiberoptic or video laryngoscopy if concern for difficult airway
• Blind nasotracheal intubation is contraindicated due to the potential for perforations and false passages

Endoscopy

Should be performed within 12-24 hours of ingestion (too early can underestimate extent of injury, too late increases risk of wound softening and perforation).

Indications

• Intentional ingestion (higher likelihood of high volume ingestion)
• Unintentional ingestion with signs of:
  • Stridor
  • Significant oropharyngeal burns
  • Vomiting
  • Drooling
  • Food refusal

Esophageal Stricture Mitigation

• Discuss with GI or medical toxicologist
• For grade IIb or higher esophageal burns:
  • Methylprednisolone (1 g/1.73 m2 per day for 3 days)
  • Ranitidine
  • Ceftriaxone
  • Total parenteral nutrition

Surgical Intervention

• Indicated for:
  • Perforation
  • Peritoneal signs

Controversial or Contraindicated

• Antibiotics
  • No evidence to support or reject the use of prophylactic antibiotics
  • Only indicated if also giving steriods (see stricture mitigation above)
• Activated charcoal
  • Only consider when coingestants pose a risk for severe systemic toxicity
• Gastric lavage
  • Contraindicated due to potential to cause reflux of caustic agent into esophagus, creating more damage
• Dilution with water or milk causes vomiting, elevating risk for perforation
  • Possible benefit only for solid alkali ingestions
• Neutralization generates excess heat
  • Milk or magnesium citrate only for hydrofluoric acid ingestion

Disposition

• All patients with symptomats from a caustic ingestion should be admitted
• All patients with intentional ingestion should be evaluated by psych prior to discharge

Prognosis

• depending severity may have full return of mobility and function or can progress to perforation followed by stricture formation
• Days 2-14 post-injury are associated with highest tissue friability / risk of perforation
• High-grade caustic burns associated with 1000x increase in esophageal SCC

See Also

• Caustic burns