The Case Files

Abstract

Figure: Pneumomediastinum and subcutaneous emphysema at the base of the neck.FigureFigureAn 18-year-old healthy man presented to the ED with a sore throat. He said the pain had started a day earlier when he took three capsules of Molly and drank heavily at a music festival. The patient reported pain while swallowing, shortness of breath, and pain in his left rib cage after playing basketball a few days earlier. The patient had no jaw or neck pain, coughing, fever, chills, nausea, vomiting, and diarrhea. He had a blood pressure of 126/76 mm Hg, temperature of 98.2°F (orally), heart rate of 70 bpm, respirations of 18 bpm, and oxygen saturation of 100% on room air. The physical exam demonstrated an alert, awake, and oriented patient with evidence of tenderness in the left rib cage. There were no signs of abdominal tenderness, respiratory distress, or asymmetrical breath sounds. The lungs were clear bilaterally, and the heart sounds were normal. The chest x-ray showed some linear air density streaks in the mediastinum. A CT with and without contrast revealed an extensive pneumomediastinum and considerable subcutaneous emphysema at the base of the neck, posterior right thoracic region, and left axillary area. The results were reviewed with the patient, but he signed out against medical advice after being told of the seriousness of his condition. The patient was advised to return if the condition worsened. Methylenedioxymethamphetamine (MDMA) is an amphetamine derivative commonly abused by young adults. It is also known as Ecstasy, Molly, Adam, Doves, and Skittles. MDMA promotes social closeness, increases energy, alters sensations, and induces euphoria. The drug has a strong affinity for serotonin receptors and transporters, causing a release of serotonin and a decrease in its uptake at the synaptic clefts. Onset is 30-60 minutes with a duration of action of eight to 24 hours. As a sympathomimetic, the initial onset can produce an elevated heart rate and anxiety. The National Institute of Drug Abuse reported that 11.6 percent of adults 18-25 have taken MDMA at least once. (Sept. 26, 2017; http://bit.ly/2RByI2H.)Figure: CT of pneumomediastinum and subcutaneous emphysema.Spontaneous pneumomediastinum can be seen in patients with underlying lung disease due to the rupture of a bleb. Other conditions that can contribute to pneumomediastinum include choking, the Valsalva maneuver, cough, extreme exertion, barotrauma, and helium gas inhalation. Fifty-five percent of spontaneous pneumomediastinum cases present with chest pain, and 40 percent present with dyspnea. Neck pain, odynophagia, and dysphagia are present in less than 20 percent of cases. Sore throat is an uncommon initial presentation that must also be taken into consideration.Figure: CT of pneumomediastinum.Ordinarily, the mean pressure in the mediastinum is more negative than the pressure in the pulmonary alveoli. In spontaneous pneumomediastinum, pressure differences rupture the alveoli, allowing free air to travel through the hilum. Air then spreads into the mediastinum by way of loose fascia. Rare Complications Pneumomediastinum and subcutaneous emphysema are rare complications of amphetamine use. The pathophysiology of pneumomediastinum after the use of amphetamines is unclear. Pharmacologically the link is yet to be determined between the stimulant and the leakage of air into the mediastinum. It is theorized that initially various mechanisms change the transmural pressure in the alveoli, which can cause rupture of the alveoli, leading to subcutaneous emphysema. The free air then reaches the mediastinum by dissecting along the bronchovascular layers and fascial planes. Commonly the transmural pressure is changed in cases that involve mechanical ventilation, the Valsalva maneuver, or an extreme straining that occurs during strenuous coughing or vomiting. In this case, an initial increase in alveolar pressure could have arisen from strenuous dancing and vigorous activity and compounded by the surge in activity due to prolonged use of MDMA. A 2011 case report found a previously healthy military trainee developed spontaneous pneumomediastinum after repeatedly yelling “hooah” in a squad competition event. (Mil Med 2011;176[3]:352.) The workup should begin with a chest x-ray to provide a definitive quantification of pneumomediastinum. It does not need to include a CBC, BNP, or CMP. Mild spontaneous pneumomediastinum is self-limiting. Patients can be managed conservatively with analgesia, rest, and by avoiding increased pulmonary pressure. Moderate to severe symptoms are treated with high-concentration oxygen, which will increase the nitrogen washout. A patient with underlying lung disease, however, should receive more aggressive measures to avoid absorptive atelectasis. It is important to understand the multifaceted presentation, pathophysiology, management, and treatment of MDMA-induced subcutaneous emphysema and pneumomediastinum.