Chapter 112. Caustics

Caustics are substances that can cause histological and functional damage on contact and include both alkalis (pH >7) and acids (pH <7). The most common alkali exposure is household bleach (sodium hypochlorite with hydroxide), which is usually benign except in intentional ingestions. The most common acid exposures are sulfuric acid (drain cleaners) and hydrochloric acid (automobile batteries and masonry cleaners).

Common features of caustic ingestions include dysphagia, odynophagia, epigastric pain, and vomiting with gastrointestinal (GI) tract injuries. Dysphonia, stridor, and respiratory distress can be seen with laryngotracheal injury. Esophageal injuries are graded by direct visualization: (1) edema and hyperemia; (2) ulcerations, blisters and exudates (2a-noncircumferential; 2b-circumferential); (3) deep ulceration and necrosis. Intentional ingestions are associated with higher-grade injury that can lead to the development of strictures. Most ingestions with serious injury are symptomatic with stridor, drooling, or vomiting, although distal GI injury without oral or facial burns is possible. Disc battery ingestions may be asymptomatic, though batteries >15 mm in diameter can become lodged in the esophagus and cause pressure necrosis.

Caustic exposures to the cornea are particularly serious if they involve alkalis. Dermal exposures to caustics usually produce only local pain and irritation. However, alkali and sodium hydrofluoric acid burns can penetrate deeply and lead to liquefactive necrosis. Hydrofluoric acid can cause systemic hypocalcemia, hypomagnesemia, and hyperkalemia with subsequent ventricular dysrhythmias.

The diagnosis is clinical. Routine laboratory tests are recommended for severely affected patients and include electrolytes, assessment of acid-base status, and monitoring for potential gastrointestinal blood loss. Monitor serum calcium and magnesium levels and perform an ECG in patients with hydrofluoric acid exposures, especially ingestions. Consider chest and/or abdominal radiographs in symptomatic caustic ingestions to assess for free air or to investigate for foreign body in cases of suspected disc battery ingestion. Noncontrast CT of the chest and abdomen may be useful if perforated viscus is suspected, especially after ingestion of strong acids. Early endoscopic evaluation (<12 to 24 hours post ingestion) is indicated for intentional caustic ingestions, and unintentional cases presenting with stridor, oral burns, vomiting, drooling, or inability to tolerate oral intake.

Focus treatment on decontamination, early anticipatory airway management, stabilization of hemodynamic status, and delineation of extent of injury.

Decontamination

1. Remove contaminated clothing and irrigate exposed skin with copious amounts of water. Alkali burns may require local debridement and removal of devitalized tissue followed by additional irrigation.

2. Perform aggressive ocular decontamination with normal saline for a minimum of 15 min with frequent monitoring of ocular pH until a pH of 7.5 to 8.0 is achieved.

3. Gastric decontamination in the form of activated charcoal, ipecac, or gastric lavage is contraindicated. Intentional strong acid ingestions may benefit from gastric decontamination with a nasogastric tube if performed within 30 min of ingestion.

4. Dilution or neutralization is generally reserved for immediate prehospital or home care of the unintentional pediatric ingestion and is not recommended more than 30 min post-ingestion.

Supportive Care

1. Perform early awake oral intubation with direct visualization in symptomatic patients with stridor, significant drooling, or dysphonia. Blind nasotracheal intubation is contraindicated.

2. Obtain IV access and administer isotonic IV fluids for hypotension.

3. Obtain surgical consultation for suspected or confirmed peritonitis or free air.

Special Considerations

1. Treat hydrofluoric acid dermal exposures with topical calcium gluconate gel (3.5 grams mixed with 150 mL water-soluble lubricant). Consider intradermal 5% calcium gluconate for large burns and calcium gluconate infusion into the radial artery over 4 hours or given as a Bier block (10 mL of 10% calcium gluconate in 40 mL saline or 5% dextrose) for refractory distal extremity burns.

2. Oral ingestions of hydrofluoric acid within an hour can be suctioned via nasogastric tube followed by instillation of up to 300 mL of 10% calcium gluconate. High doses of IV calcium and magnesium may be needed to treat systemic deficiencies and dysrhythmias.

3. Disc batteries lodged in the esophagus require emergent endoscopic removal.