Cardiovascular collapse induced by position-dependent pulmonary vein occlusion in a patient with fibrosing mediastinitis.

FIBROSING mediastinitis is a rare disease characterized by an abnormal proliferation of fibrous tissue and acellular collagen within the mediastinum. Most cases of fibrosing mediastinitis in the United States are caused by an exaggerated granulomatous immunologic response to Histoplasma capsulatum infection. However, other possible etiologic conditions include tuberculosis, mediastinal malignancy, and autoimmune diseases. In advanced stages of the disease, these patients may have signs and symptoms of extrinsic compression of airways, intrathoracic vessels, or the esophagus. We describe a patient with fibrosing mediastinitis who, after sedation, awake tracheal intubation, and being positioned supine, experienced acute cardiovascular collapse due to occlusions of the pulmonary veins. It is well known that patients with anterior mediastinal mass can experience posture-dependent compression of airways, vascular structures, or both. However, our case is the first report of position-dependent occlusion of pulmonary venous outflow associated with a disease that is primarily distributed throughout the middle mediastinal compartment.