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A3936 - Spontaneous Pneumomediastinum and Pneumoperitoneum as a Complication of Severe Asthma Exacerbation
Author Block: P. Shah1, A. Chauhan2, A. Sharma2; 1Department of Internal Medicine, University of Connecticut, Farmington, CT, United States, 2University of Connecticut, Farmington, CT, United States.
Asthma remains one of the most prevalent respiratory diseases worldwide and in the United States. It accounts for more than 2 million emergency room visits annually for exacerbations or related complications. Rare, but life-threatening, complications of severe asthma exacerbation include spontaneous pneumomediastinum (SPM) and subcutaneous emphysema (SE), with an incidence of less than 1 percent. Even more uncommon is the co-occurrence of pneumoperitoneum. Here we present a case of severe asthma exacerbation complicated by SPM and pneumoperitoneum. A 38-year-old male with a history of moderate persistent asthma presented with acute respiratory distress due to severe asthma exacerbation. He was found to be in acute hypoxic hypercarbic failure with an ABG showing a pH of 6.8, pCO2 of >150 and pO2 of 48 and he was intubated. Initial chest radiograph showed potential pneumothorax in the medial left hemithorax and subcutaneous emphysema. There also was difficulty ventilating him requiring a reduction in PEEP from 10 to 5. Subsequently, a CT of the chest, abdomen, and pelvis was performed, which showed extensive SPM and pneumoperitoneum without evidence of trauma or organ perforation. A bedside chest tube was placed in the mediastinum with near resolution of the SPM. Concomitantly, he was also maintained on intravenous corticosteroids, continuous bronchodilators, and sedation for optimal mechanical ventilation. A follow-up abdominal ultrasound within 24-36 hours was negative for any intra-peritoneal free air. The patient showed steady improvement in his respiratory status and was discharged home after 1 week. Spontaneous pneumomediastinum is an uncommon and self-limiting condition. Some well-described triggers include severe asthma, cough, inhaled drugs, physical exercise, Valsalva etc and infrequently esophageal and tracheal injury. A likely mechanism is rupture of overly distended alveoli under high pressure in the presence of a sufficient alveolar-interstitial gradient. The free air then dissects along the bronchovascular sheaths toward the mediastinum and can further pass through the diaphragm via hiatus aorticus, hiatus esophagus, or sternocostal triangle, resulting in pneumoperitoneum, what is called the Macklin effect. CT scan is required for diagnosis and management is usually conservative. However, patients with Macklin effect involving peribronchovascular air and pneumatocele have prolonged SPM often requiring invasive intervention. However, more data is required to extrapolate that complicated SPM, such as our case with concomitant SPM and pneumoperitoneum, may benefit from early chest tube placement.