Pharyngeal burns can occur due to accidental ingestion of high-temperature liquids or chemical corrosive agents. In addition to causing local mucosal damage, severe cases may result in serious systemic pathological changes and toxic symptoms, potentially leading to asphyxia, heart failure, or death.
Etiology
Pharyngeal burns are categorized into two major types: thermal burns and chemical burns.
Thermal burns are caused by flames, high-temperature steam, boiling food or liquids, and are more common in young children.
Chemical burns are often the result of accidental ingestion of strong acids, strong alkalis, heavy metal salts, or solutions like phenol.
Pathology
The severity of pharyngeal tissue burns depends on factors such as the temperature, concentration, nature, quantity, and exposure duration of the injuring substances. Generally, burns are classified into three degrees of severity:
- First degree (Mild): The damage is confined to the mucosal layer, characterized by mucosal congestion and edema without significant damage. Healing occurs without residual scar formation or stenosis.
- Second degree (Moderate): The burn affects both the mucosal and muscle layers, often causing local ulceration with exudation or formation of pseudomembranes. Scar formation is common during the healing process.
- Third degree (Severe): The mucosal injury is most severe, leading to deep necrosis, where necrotic pseudomembranes may take 3–4 weeks to resolve. Scar formation and adhesions may result in pharyngeal stenosis or even complete obstruction.
Clinical Manifestations
Symptoms include immediate oral and pharyngeal pain, swallowing pain, and difficulty swallowing. These may be accompanied by drooling and coughing. Hoarseness and respiratory distress may occur if laryngeal edema is present. Severe burns are often associated with fever and other signs of intoxication.
Examinations
The oral and pharyngeal mucosa may show blistering, erosion, or white membrane formation on the surface. In cases of mild burns without secondary infection, the white membrane typically resolves, and the wound heals within a week. Severe burns may result in scar adhesion and pharyngeal-laryngeal stenosis or even complete obstruction within 2–3 weeks.
Treatment
Severe burns with progressively worsening respiratory distress may necessitate a tracheotomy.
For burns caused by strong acids or alkalis, immediate neutralization therapy may be administered. Vinegar, orange juice, lemon juice, or egg white may neutralize alkalis, while milk of magnesia, aluminum hydroxide gel, or milk may neutralize acids. Sodium bicarbonate (baking soda) is avoided due to the risk of carbon dioxide production, which may increase the danger of esophageal or gastric perforation.
Antibiotics may be used for infection control.
Glucocorticoids can help prevent and reduce laryngeal edema and inhibit connective tissue proliferation.
Mild burns may be treated with topical application of 3% tannic acid, liquid paraffin, lithospermum oil, or bismuth subcarbonate powder to protect the wound surface.