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

1. Intentional ingestion (higher likelihood of high volume ingestion)
2. Unintentional ingestion with signs of:
   1. Stridor
   2. Significant oropharyngeal burns
   3. Vomiting
   4. Drooling
   5. 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