Where Is the Bubble: Atypical and Unusual Thoracic Air D
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WHERE IS THE BUBBLE: ATYPICAL AND UNUSUAL THORACIC AIR D. Varona Porres*, O. Persiva*, E. Pallisa*, J. Andreu* Vall de Hebrón Hospital. Barcelona (Spain) *No relevant financial disclosures. LEARNING OBJECTIVES . To review unusual and atypical conditions with presence of air in the thorax. To describe the radiological findings that allows diagnosis on chest radiography and multislice CT in these patients. To emphasize the importance of diagnosis for management of these patients and its clinical impact. CONTENT: Location of the thoracic air MEDIASTINAL: PERICARDIAL: related CARDIOVASCULAR: PLEURAL: related to CHEST WALL: spontaneous (with to progression of air embolism. interstitial lung intercostal hernias pneumorrhachis and lung neoplasm or disease, lung with pulmonary or related to interstitial lung transplantation. neoplasm or gastrointestinal lung disease), mesothelioma, content, infections, pneumoperitoneum infections, and and subcutaneous wiith bilateral emphysema of pneumomediastinum, pneumothorax post- unusual causes bronchial or lung biopsy. (post-pulmonary esophageal fistula biopsy). post-lymph node perforation. MEDIASTINAL: Pneumomediastinum PNEUMOMEDIASTINUM (PM) CONCEPT AND PATHOGENESIS: Free air or gas in mediastinum. Spontaneous PM pathogenesis by “Macklin Effect”: Air ruptures from the alveolus to the perivascular and peribronchial fascial sheath (due to pressure gradient between alveoli and interstitium). Continued insufflation causes air overflow into the retroperitoneum, anterior mediastinum, and subcutaneous tissues of the neck and chest wall. ANATOMY: Communication of mediastinum with: 1.Neck: Submandibular space, retropharyngeal space, and vascular sheaths. 2.Retroperitoneum: Sternocostal attachment of the diaphragm (continous with flanks and pelvis), and periaortic and periesophageal plane. CAUSES: Spontaneous or secondary. Potential sources: 1.Intrathoracic: Trachea and main bronchi, esophagus, lung, pleural space, or gas-forming bacterias. 2.Extrathoracic: Head and neck, and intraperitoneum and retroperitoneum. DIAGNOSTIC IMAGING: 1.Chest radiograph: Pneumoprecardium, ring around the artery sign (air surrounding right pulmonary artery), tubular artery sign, double bronchial wall sign, continuous diaphragm sign, or extrapleural sign. 2.CT: Specially useful in central airways or esophageal injuries. MEDIASTINAL SPECIAL CONDITIONS OF MEDIASTINAL AIR SPONTANEOUS PM WITH PNEUMORRHACHIS: Pneumorrhachis consists on air within spinal canal. Most often from trauma or spine surgery, but also with spontaneous PM (9.5% pediatric patients with spontaneous PM). Extension of the air along the fascial planes of the submandibular and retropharyngeal spaces through the neural foramina into the epidural space. Usually, asymptomatic and self-limited. SPONTANEOUS PM RELATED TO INTERSTITIAL LUNG DISEASE: 11,2% of extra-alveolar air in CT (pneumothorax and PM) in one series of patients with idiopathic pulmonary fibrosis. Clinical manifestations from asymptomatic to severe respiratory insufficiency. PM WITH PNEUMORETROPERITONEUM: Dissection of the air into mediastinum from the retroperitoneal space following perforation of a hollow viscus. TRACHEAL RUPTURE: 15-27% of all tracheobronchial injury. High morbidity and mortality. Causes: blunt chest trauma or intubation. Diagnosis delayed as a result of rare incidence, and nonspecific clinical and radiologic manifestations. Predominantly, membranous portion of the intrathoracic trachea involved. Diagnostic imaging: 1.Chest radiograph: Pneumomediastinum, pneumothorax and progressive extrapulmonary soft-tissue air. 2.CT: Focal defect or circunferential absence of tracheal wall, contour deformity, abnormal communication with other mediastinal structures, overdistention of the endotracheal tube balloon or herniation of endotracheal tube balloon, and extraluminal position of endotracheal tube. MEDIASTINAL: Spontaneous PM with pneumorrhachis Fig. 1. 63 y.o. woman with dyspnoea. Chest radiograph showed air delimiting the aortic knob and subcutaneous emphysema in frontal projection (white arrows). Lateral projection of the chest radiograph demonstrated air outlining the anterior wall of the intrathoracic trachea and bronchi and the anterior cardiac border (pneumoprecardium) (white arrows). CT clearly depicts the extension of air into the spinal canal (black arrows). This patient was diagnosed of spontaneous PM with pneumorrhachis. Follow-up CT demonstrated resolution of all of these radiological findings. MEDIASTINAL: PM related to interstitial lung disease Fig. 2. 68 y.o. woman with UIP (Usual Interstitial Pneumonia) diagnosis 5 years ago. Worsening of respiratory symptoms with small efforts dyspnoea. Spontaneous PREVIOUS CT (2 months ago) pneumomediastinum (black arrows) and increase in the extension of ground glass opacities in relation to interstitial pneumonia progression with respect to previous CT 2 months ago. MEDIASTINAL: PM related of perforation of sigma Fig. 3. 70 y.o. man with fever and abdominal pain on the left flank. CT showed bilateral pulmonary nodules and PM (black arrows). Multiplanar reconstruction on sagital and coronal planes clearly demonstrated the passage of intra-abdominal air through the esophageal hiatus (white arrows). CT also demonstrated pneumoperitoneum caused by sigma perforation probably related to diverticulitis (white arrows). MEDIASTINAL: Tracheal rupture post-intubation Fig 4. 36 y.o. woman. Autolysis attempt with benzodiazepines intake. Acute respiratory insufficiency with progressive respiratory deterioration and chest and cervicofacial subcutaneous emphysema after intubation. Chest radiograph showed massive subcutaneous emphysema, endotracheal tube balloon overdistention (white arrows) with distal end located into proximal segment of the left main bronchus (black arrow). CT showed bilateral pneumothorax, endotracheal tube balloon overdistention (white arrow) and posterior tracheal wall deformity due to tracheal rupture, specially evident on MinIP reformatted images (black arrow). Treatment consisted in double chest tube insertion for bilateral pneumothorax and selective intubation of right main bronchus with succesful extubation after 36 hours. MEDIASTINAL SPECIAL CONDITIONS OF MEDIASTINAL AIR DEHISCENCE OF BRONCHIAL ANASTOMOSIS IN LUNG TRANSPLANTATION: Risks factors of bronchial anastomotic complications (overall prevalence approx. 15%): donor bronchus ischemia caused by disruption of the native bronchial circulation, recurrent infection, and rejection. First month after lung transplantation. CT findings: bronchial wall defect, bronchial narrowing, bronchial wall irregularity, extraluminal air, PM, pneumothorax, and ipsilateral lung volume loss. Bronchospcopy may identify mucosal necrosis, the earliest sign and a useful predictor of this complication. Clinical evolution: no sequelae, stricture that requires stent, or fatal. INTRAMUCOSAL ESOPHAGEAL DISSECTION (IED): Separation of mucosa and/or submucosa from deeper muscular layers due to abrupt increases in intraesophageal pressure. Causes: Spontaneous (women in their 7th or 8th decade, often with anticoagulation), iatrogenic (endoscopy), foreign body, and repeated episodes of retching or vomiting. Diagnosis: esophagography, CT (submucosal air and no extravasation of oral contrast in contained perforation; subcutaneous emphysema and PM in perforation), endoscopic ultrasound and/or standard endoscopy. Conservative management. BOERHAAVE SYNDROME: Complete transmural laceration of the esophagus from violent straining or vomiting (increase in intraesophageal pressure). High mortality and morbidity. Middle-aged men with history of alcoholism (50%). Mackler triad of symptoms: vomiting, sudden chest pain, and subcutaneous emphysema. Location: left posterior wall of the lower one-third of the esophagus, about 2 m long and 3-6 c m a b o v e the diaphragm. Chest radiograph: widening of mediastinum, PM, subcutaneous emphysema, pleural effusion (left side), hydropneumothorax, and patchy pulmonary opacities. Esofagography: extravasation of contrast. CT: esophageal wall thickening, periesophageal air, PM, and esophagopelural fistula (left side). Treatment: conservative, endoscopic or surgical. MEDIASTINAL: Dehiscence of bronchial anastomosis in lung transplantation Fig 5. 67 y.o. man with right lung transplantation. Coronal MinIP reformatted images revealed mediastinal air in the vicinity of bronchial anastomosis probably due to surgical suture failure (white arrows) and right pneumothorax. Treatment consisted in right main bronchus endoprosthesis placement. Fig 6. Forms of presentation of bronchial anastomosis suture failure. A. Localized pneumomediastinum near surgical suture. B. Massive pneumomediastinum. C. Bronchopleural fistula. White line: Bronchial anastomosis surgical suture. Black areas: Air. MEDIASTINAL: Intramucosal esophageal dissection Fig 7. 20 y.o. man with previous endoscopy to assess esophageal alimentary impaction. CT showed pneumomediastinum and air images probably within the submucosal esophageal layer (white arrows) along with pneumoperitoneum and pneumoretroperitoneum (black arrows). After administration of oral contrast, CT did not demonstrate contrast leaking, localized in submucosa (black arrows). Esophagography showed no oral contrast leaking. Conservative management was carried out with complete resolution of the radiological findings on follow-up. MEDIASTINAL: Boerhaave Syndrome Fig. 8. 36 y.o. woman presenting with abdominal pain after vomiting. CT reveals pneumomediastinum