Disorders of the Mediastinum

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The region between the pleural sacs. It is separated into three compartments: »

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extends from the sternum anteriorly to the pericardium and brachio- cephalic vessels posteriorly. It contains the thymus gland, the anterior mediastinal lymph nodes, and the internal mammary arteries and veins. lies between the anterior and posterior mediastina contains the heart; the ascending and transverse arches of the aorta; the venae cavae; the brachiocephalic arteries and veins; the phrenic nerves; the trachea, the main bronchi, and their contiguous lymph nodes; and the pulmonary arteries and veins. is bounded by the pericardium and trachea anteriorly and the vertebral column posteriorly. It contains the descending thoracic aorta, the esophagus, the thoracic duct, the azygos and hemiazygos veins, and the posterior group of mediastinal lymph nodes.

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first step in evaluating a mediastinal mass is to »

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The most common lesions in the : o Thymomas Lymphomas o o Teratomatous neoplasms o thyroid masses The most common masses in the : o vascular masses o lymph node enlargement from metastases or granulomatous disease, o pleuropericardial o bronchogenic cysts. In the : neurogenic tumors o meningoceles o o meningomyeloceles o gastroenteric cysts o esophageal diverticula  is the most valuable imaging technique for evaluating mediastinal masses and is the only imaging technique that should be done in most instances.  of the gastrointestinal tract are indicated in many patients with posterior mediastinal lesions, because hernias, diverticula, and achalasia are readily diagnosed in this manner. An  can efficiently establish the diagnosis of intrathoracic goiter. A definite diagnosis can be obtained with  in many patients with masses in the anterior or middle mediastinal compartments. A diagnosis can be established otomy via or endoscopic transesophageal or endobronchial ultrasound-guided biopsy of mediastinal masses in most cases.

Most cases are due to , but sarcoidosis, silicosis, and other fungal diseases are at times causative. Most pxs are asymptomatic Those with  usually have signs of  of a mediastinal structure

 in the interstices of the mediastinum. The  are: (1) alveolar rupture with dissection of air into the mediastinum; (2) perforation or rupture of the esophagus, trachea, or main bronchi; and (3) dissection of air from the neck or the abdomen into the mediastinum. : severe substernal chest pain with or without radiation into the neck and arms  subcutaneous emphysema in the suprasternal notch and Hamman’s sign, which is a crunching or clicking noise synchronous with the heartbeat and is best heard in the left lateral decubitus position : confirmed with the chest radiograph. Usually  is required

Most cases of acute mediastinitis either are

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: includes immediate drainage, debridement, and parenteral antibiotic therapy, but the mortality rate still exceeds 20%.

 for cardiac surgery. : wound drainage . Other presentations include sepsis and a widened mediastinum. : mediastinal needle aspiration. 1