Esophageal corrosive injury (caustic injuries of the esophagus) refers to esophageal mucosal damage caused by the accidental or intentional ingestion of caustic agents. Common caustic agents include acidic and alkaline substances. Strong acids include sulfuric acid, hydrochloric acid, and nitric acid, while alkaline substances include sodium hydroxide (caustic soda, lye), potassium hydroxide, and sodium bicarbonate (baking or cleaning soda).
Pathology
The severity of the injury depends on the nature, concentration, dosage, and duration of exposure to the caustic agent. Alkaline corrosive agents exhibit strong hygroscopic properties and induce fat saponification and protein dissolution, leading to tissue liquefaction necrosis. These injuries often penetrate deeply into tissues due to their strong penetrative ability. Acidic caustic agents generally cause localized mucosal coagulative necrosis with weaker penetration. However, high concentrations of strong acidic agents can also cause severe esophageal damage.
Based on the severity of the injury observed during endoscopy, esophageal corrosive injuries are classified into five grades:
- Grade 0: Normal esophageal mucosa.
- Grade 1: Damage is confined to the mucosal layer, with superficial congestion, swelling, necrosis, and shedding of the mucosa. Healing typically occurs without residual scar formation or stricture.
- Grade 2: Subdivided into Grade IIa and Grade IIb:
- Grade IIa: Mucosal erosion, bleeding, and superficial ulcers, with a low likelihood of stricture formation.
- Grade IIb: In addition to the features of Grade IIa, deeper ulcers are observed, with a higher risk of stricture formation but a lower risk of perforation.
- Grade 3: Subdivided into Grade IIIa and Grade IIIb:
- Grade IIIa: Scattered areas of necrosis on the esophageal mucosa, with a very high risk of stricture formation and a higher risk of perforation compared to Grade IIb.
- Grade IIIb: Extensive mucosal necrosis, with an extremely high risk of both stricture and perforation.
- Grade 4: Esophageal perforation, which is often fatal.
Clinical Manifestations
Acute Phase (approximately 1–2 weeks)
Local symptoms
Pain
Pain in the mouth, throat, retrosternal area, or back may occur immediately after caustic agent ingestion.
Dysphagia
Hesitation or fear of swallowing due to pain, is often accompanied by drooling and nausea.
Hoarseness and Dyspnea
Hoarseness or symptoms of laryngeal obstruction may arise if the caustic agent affects the larynx, leading to laryngeal edema.
Systemic Symptoms
Severe cases may involve systemic toxicity, presenting with fever, dehydration, coma, or shock.
Relief Phase
In 1–2 weeks, systemic symptoms begin to improve, the wounds gradually heal, and pain and dysphagia subside. Mild cases may heal within 2–3 weeks, with restoration of normal dietary intake.
Stricture Phase
In 3–4 weeks or longer, in cases where the injury extends to the muscular layer, local connective tissue proliferation and subsequent scar contraction may lead to esophageal stricture. Dysphagia reappears and progressively worsens. Mild cases may only tolerate liquids, while severe cases may be unable to swallow even small amounts of water, resulting in dehydration, malnutrition, and other systemic symptoms.
Examinations and Diagnosis
Diagnosis is typically straightforward based on a history of caustic agent ingestion and characteristic symptoms. However, detailed information about the nature, concentration, dosage, and time of ingestion of the caustic agent should be obtained.
For emergency patients, examination of the lips, oral cavity, and pharyngeal mucosa can help identify signs such as congestion, swelling, mucosal shedding, ulcers, and pseudomembrane formation. Indirect laryngoscopy may be performed when appropriate to evaluate the condition of the hypopharynx and larynx.
Radiological Examination
When complications are suspected, chest and abdominal X-ray fluoroscopy, imaging, or CT scans may be used. Esophageal barium swallow or iodinated contrast imaging should be performed after the acute phase to assess the nature, location, and extent of the injury. However, barium studies should be avoided or used with caution if esophageal perforation is suspected. Patients at risk for esophageal stricture should undergo regular follow-up examinations within 2–3 months if the initial findings are normal. CT can complement endoscopy by providing additional information and aiding in the grading of esophageal injuries.
Esophagoscopy
This is the primary method for directly observing esophageal injury. It should be performed at the appropriate time, typically around 2 weeks after the injury. Performing an esophagoscopy too early carries a risk of perforation. Flexible esophagoscopy is safer than rigid esophagoscopy. Endoscopic techniques such as ultrasound endoscopy or electronic gastroscopy may also be utilized.
Treatment
Acute Phase
Early Rinsing with Water
For patients who are able to swallow, articulate clearly, and breathe without difficulty, rinsing the oral and pharyngeal cavities or removing corrosive materials adhered to the esophagus with water immediately after ingestion (typically at home) can help mitigate the damage. Early rinsing is particularly useful in cases where powdered corrosive agents have been ingested, as it can wash away adhered particles and delay further injury. While addressing injuries to the airway and digestive tract, consideration must also be given to the potential harm caused by splashing, spilling, or vomiting of corrosive materials, which may damage the skin and eyes. Immediate removal of clothing and thorough skin rinsing with large amounts of water are essential. If eye injury is suspected, immediate irrigation of the eyes should be performed, and consultation with an ophthalmologist is recommended for further guidance and treatment.
Use of Neutralizing Agents
Although the efficacy of neutralizing agents has not been clinically confirmed, they may be used promptly after injury. However, they are generally ineffective if used several hours later. For alkaline corrosive agents, small amounts of vinegar, 2% acetic acid, orange juice, or lemon juice may be used for rinsing or oral intake. For acidic corrosive agents, aluminum hydroxide gel or magnesium oxide suspension may be administered first, followed by milk, egg whites, or vegetable oil. The use of soda water for neutralization is contraindicated, as it produces carbon dioxide gas, which may pose a risk of esophageal perforation. Additionally, heat generated during the neutralization process may cause thermal injuries, and mucosal swelling during the reaction could lead to further tissue damage or vomiting.
Use of Antibiotics
Broad-spectrum antibiotics at sufficient doses are recommended early to prevent infection.
Use of Glucocorticoids
Glucocorticoids may help reduce inflammatory responses, alleviate shock, diminish edema, inhibit fibrogranuloma formation, and prevent scar-related esophageal stricture. However, indications and dosage should be strictly controlled. Excessive dosages may facilitate the spread of infection and increase the risk of esophageal perforation. Therefore, glucocorticoids are not suitable for severe burns or suspected esophageal perforation.
Systemic Treatment
Pain relief, sedation, and anti-shock therapy may be administered, as needed. Intravenous fluids or blood transfusions may help correct electrolyte imbalances and restore blood volume. Once the condition stabilizes slightly, cautious nasogastric tube insertion can support nutritional intake and help maintain esophageal patency to prevent stricture formation.
Sucralfate and Mitomycin C
Clinical studies have suggested that these two drugs may be effective in treating corrosive injuries.
Tracheostomy
For cases with significant laryngeal obstruction symptoms, a tracheostomy may be performed to ensure an open airway.
Recovery Phase
Antibiotics and glucocorticoids may be used for a few weeks, with gradual dosage reduction until discontinuation, depending on the severity of the condition.
After the acute phase, esophageal X-ray imaging with barium contrast or endoscopic examination may be performed to evaluate the extent of damage. Regular follow-ups may be necessary to detect potential esophageal strictures early and address them promptly.
Scar Formation Phase
For patients who develop esophageal strictures due to scar formation, the following treatment methods may be considered:
Endoscopic Dilation with Bougies
This is suitable for patients with mild and localized strictures. Bougies made of materials such as metal or silicone may be inserted under direct endoscopic guidance, starting with smaller sizes and gradually increasing in diameter. The procedure is typically performed once a week until normal swallowing is restored.
String-Guided Esophageal Dilation
This includes antegrade, retrograde, or loop dilatation methods, with the latter two being more commonly used. This approach is suitable for multiple or long-segment strictures. It usually involves a prior gastrostomy. In the retrograde method, a thick thread with a small metal bead is passed through the mouth and retrieved through the gastrostomy site, where it is attached to a cone-shaped dilator of appropriate size. The thread is then pulled upwards through the mouth, guiding the dilator retrogradely from the stomach into the esophagus and through the stricture. In the loop method, both ends of the thread are attached to the dilator, forming a loop. The loop is pulled retrogradely into the mouth and then back down through the gastrostomy site, allowing repeated dilations by moving the dilator back and forth across the stricture. This method is performed 2–3 times a week, with progressively larger dilators.
Endoscopic Esophageal Metallic or Memory Alloy Stent Placement
Techniques involving the use of titanium or memory alloy stents may be employed for stricture dilatation.
Surgical Treatment
In cases of severe esophageal strictures where the above methods prove ineffective, surgical intervention may be necessary. Depending on the condition, options may include resection of the stricture segment with end-to-end esophageal anastomosis, colonic interposition, free jejunal graft transplantation, or esophagogastrostomy.
Prevention
Esophageal corrosive injury is preventable. Proper storage and management of corrosive agents, such as strong acids and alkalis, is essential. Clear labeling on containers and supervised, locked storage are recommended. Corrosive substances intended for household use should be kept out of children’s reach. It is particularly important to avoid storing such substances in beverage bottles or leaving them in random locations to prevent accidental ingestion.