Hydrochloric acid

Background

• Strong acid, causes coagulation necrosis due to denaturation of proteins
• Most household bleaches are only 3-6% hydrochlorite solutions, but patients may have occupational exposures if working in steel picking, chemical manufacturing, oil/gas-well acidizing, and food processing
• HCl is combustion product of polyvinyl chloride (PVC), can cause chemical inhalation injury, can persist in air for up to an hour after fire extinguished

Clinical Features

• Can be systemically absorbed and → metabolic acidosis, hemolysis, AKI
• Dermal caustic burns
• Ingestion
  • All patients with serious esophageal injuries have some initial sign/symptom
  • Dysphagia, odynophagia, epigastric pain, vomiting
  • Laryngotracheal injury: dysphonia, stridor, respiratory distress
    • Occurs via aspiration of caustic or vomitus or inhalation of acidic fumes
• inhalation injury
  • PVCs and other arrhythmias
  • Delayed onset (2-12 hours) pulmonary edema
  • Dyspnea, chest pain
• Caustic keratoconjunctivitis
  • Severe eye pain, blepharospasm, reduced visual acuity
  • Altered ocular pH (normal = 7.0-7.2)
  • Conjunctival injection OR blanching, chemosis, hemorrhage, epithelial defects, corneal loss OR edema, perilimbal ischemia (white ring around iris)

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
• CBC, metabolic panel, lactate, serum calcium (if concern for hydrofluoric acid exposure
• ECG
• Tylenol/ASA levels if concerned about coingestion (suicidal patients)
• Ingestion, consider:
  • 3-View CXR: look for free air under diaphragm or mediastinal free air
  • CT: if suspect perforation but CXR negative

Management

• Decontaminate first: use appropriate personal protective equipment, remove all patient's clothing, decontaminate patient
• Irrigate areas of dermal or ocular exposure, early and copiously!
• 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 in caustic ingestion due to the potential for perforations and false passages
  • Bronchodilators for bronchospasm if concern for inhalational injury

Systemic Exposure

• Metabolic acidosis: consider bicarbonate for severe acidosis
• Severe hemolysis may require exchange transfusion

Ingestion

• Airway management especially important!
• Endoscopy
  • Indications:
    • All intentional ingestions (higher likelihood of high volume ingestion)
    • Any ingestion with stridor, drooling, significant oropharyngeal burns, vomiting, food refusal
  • Perform within 12-24 hours of ingestion (too early can underestimate extent of injury, too late increases risk of wound softening and perforation)
• Esophageal stricture mitigation
  • Discuss with GI or toxicologist
  • 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 if perforation or peritoneal signs
• Contraindicated (or controversial) therapies:
  • Antibiotics (unless giving steroids]]
  • Activated charcoal (may 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
  • Neutralization (e.g. with milk or mag citrate): generates excess heat

Ocular exposure

• Irrigate, immediately and copiously!
  • NS, LR, or BSS (Buffered Saline Solution) preferred in the hospital setting, but tap water is acceptable, especially in pre-hospital setting
  • Use of morgan lens or eyelid speculum will assist with getting more fluid in contact with cornea
  • Goal is to remove caustic agent and restore normal ocular pH (7.0-7.2)
  • Do NOT attempt to neutralize pH by adding base to an acidic burn or acid to an alkali burn
• Remove particulate matter
  • Evert both lids, remove any visible particulate matter with cotton-tipped applicator
• Anesthesia
  • Topical anesthetic (e.g. tetracaine) to help with discomfort.
  • Other options include cycloplegics (e.g. atropine, cyclopentolate), IV/IM/PO analgesics
• Antibiotics
  • Erythromycin ophthalmic ointment QID for minor burns
  • Topical fluoroquinolone for more severe burns
• Control inflammation
  • Topical steroids - prednisolone 1% ophthalmic QID for 1 week
  • Limit topical steroid use to 10 days to avoid corneal breakdown.
• Ophtho consultation for all but minor burns (Severe exposures may require debridement or other surgical intervention)

Disposition

• Dependant on severity of exposure and complications

See Also

• Caustic burns, Caustic ingestion, Caustic keratoconjunctivitis, Inhalation exposure

References

Authors

Claire, Michael O'Brien, MD