Soft Palate and Uvula Thermal Burn Injury in an Adolescent Following Recreational Inhalation of Nitrous Oxide.

Thermal injury refers to trauma to tissues as a result of exposure to a source of sufficiently high or low temperature. This mechanism of trauma may arise from direct contact with a heat source, e.g., scalding of skin secondary to immersion in hot water or following exposure to a stimulus below freezing temperature. Gases stored under pressure in a liquid state undergo adiabatic expansion upon decompression, which results in a rapid and significant decrease in temperature. Nitrous oxide is an example of a gas typically stored as a liquid in canisters prior to use. Tissue exposed to decompressed nitrous oxide undergoing adiabatic cooling can experience significant thermal injury, resulting in inflammation and, in severe cases, necrosis. A 16-year-old girl presented to the Pediatric Emergency Department (ED) with marked dysphagia, odynophagia, and dysphonia, three days following recreational inhalation of nitrous oxide (N2O) gas from a canister. The patient reported on assessment that she had recreationally inhaled directly from a canister of compressed N2O during a recent party. She experienced diffuse throat pain following one breath and immediately stopped. Worsening dysphagia and dysphonia persisted over the following three days, and she attended the pediatric ED with her mother. The patient was otherwise healthy with no relevant medical history. Examination demonstrated a stable airway with ulceration and slough tissue at the soft palate and base of the uvula, secondary to thermal burn injury. She was apyrexic and observations were reassuring. Blood tests revealed a mildly elevated C-reactive protein (CRP) of 21 mg/L with otherwise unremarkable markers. A decision was made to admit under the Ear, Nose, and Throat (ENT) team. Regular intravenous dexamethasone, co-amoxiclav, and analgesia were subsequently initiated. Following an expeditious recovery, the patient had improved quality of voice, tolerated a soft diet, and was discharged with a course of antibiotics and betamethasone mouthwash. Nitrous oxide, abused recreationally for its euphoric effects, is one of the most widespread illicit substances in the United Kingdom. While systemic sequelae, such as N2O-induced subacute spinal cord degeneration, are well-documented, there are few reports in the literature of localised thermal trauma to airway structures upon inhalation. This case aims to raise awareness of such complications, especially in adolescents, and to discuss ENT approaches to management.