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

Diagnosis

• 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

Work-Up

Labs

Only necessary in patients with significant injury or volume of ingestion

Consider:

• CBC
• Chemistry
• Lactic Acid
• Lactate
• Calcium level (if Hydrofluoric Acid exposure)
• ECG
  • May show QT-prolongation if hypocalcemic secondary to HF acid
• Screens for tylenol levels in suicidal patients at risk for congestions

Imaging

• Upright CXR
  • Look for free air under the diaphragm indicating a perforation or mediastinal air
• CT
  • Consider when perforated viscus is suspected based on severity of ingestion or peritoneal signs on exam

Treatment

First prevent personal exposure to the caustic agent by removing all clothing and decontaminating the patient

Airway Management

• First-line is awake oral intubation with direct visualization
  • Should be considered as a difficult airway
  • Blind nasotracheal intubation is contraindicated due to the potential for perforations and false passages
  • LMAs, combitubes, bougies are probably may be safe depending on the type of caustic ingestion
  • Consider surgical back-up

Steroids

• Some toxicologists recommend single dose of dexamethasone 10mg IV (0.06mg/kg in peds) with the thought of decreasing esophageal stricture formation
• Steroids may potentiate mortality in more severe esophageal caustic injuries
• Only administer under direction from a medical toxicologist

Endoscopy

Should be performed <12hr after ingestion and no later than >24hr after ingestion

Indications

1. Intentional ingestion
2. Unintentional ingestion with signs of:
   1. Stridor
   2. Significant oropharyngeal burns
   3. Vomiting
   4. Drooling
   5. Food refusal

Surgical intervention

• Indicated for perforations, peritoneal signs, free intraperitoneal or mediastinal air

=Controversial or Contraindicated

• Antibiotics
  • No evidence to support or reject the use of prophylactic antibiotics
• 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

Disposition

• All patients with symptomatic from a caustic ingestion should be admitted

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

Source

• Riffat F, Cheng A. Pediatric caustic ingestion: 50 consecutive cases and a review of the literature. Dis Esophagus. 2009;22(1):89-94. 2008 Oct 1. PMID: 18847446
• Zargar S et al. Ingestion of strong corrosive alkalis: spectrum of injury to upper gastrointestinal tract and natural history. The American Journal of Gastroenterology. 1992 87 (3), 337-41 PMID: 1539568