Transudative pleural effusions may result from the superior vena cava (SVC) syndrome. The most frequent benign etiology of the SVC syndrome is fibrosing mediastinitis, which is often related to previous histoplasma infection. Herein, we describe a case of a woman who developed the SVC syndrome 24 years after she was diagnosed with fibrosing mediastinitis, and her excellent response to surgical therapy.
An otherwise healthy 53 year-old woman, non-smoker, presented in late 2002 with progressive dyspnea and hypoxemia related to recurrent bilateral pleural effusions over the previous six months. In 1978, because of an abnormality on a routine chest x-ray, she was diagnosed with fibrosing mediastinitis based upon an open lung biopsy. She remained asymptomatic, however, until her current presentation 24 years later. Over this six month period, she underwent multiple thoracenteses, which revealed transudative effusions. The pleural taps temporarily relieved her symptoms, only for the effusions to quickly recur. Physical examination revealed dilated veins along the anterior chest and upper extremities. CT chest demonstrated calcified mediastinal thickening and right hilar lymph nodes, obliteration of the SVC, and venous collateral circulation along the chest wall. Upper extremity venography (see Figure) showed obliteration of the SVC at the junction of the innominate veins and a large caliber azygous vein with collaterals. To exclude chronic pericardial disease as a cause of transudative pleural effusions, a right and left heart catheterization was performed, which revealed pulmonary hypertension and otherwise normal chamber pressures and function. Due to worsening symptoms and hypoxemia, the patient underwent surgical reconstruction of the SVC via a left innominate vein to right atrium bypass using a spiral saphenous vein graft. Ten months later, the patient is asymptomatic, chest and abdominal wall veins have regressed in size, and pleural effusions have not recurred.DISCUSSION: Although rare, particularly in cases associated with a non-malignant origin, SVC syndrome can cause transudative pleural effusions. It should be considered in atypical presentations, such as in patients without a history of cardiac, renal or hepatic disease. Suspicion should be high in cases of pre-existing fibrosing mediastinitis, which may precede the syndrome by several years. The pathophysiology of transudative pleural effusions secondary to SVC syndrome is thought to be related to elevated central venous pressures, despite often well-developed collateral circulation.Symptomatic SVC syndrome due to long standing fibrosing mediastinitis may present a difficult treatment problem. However, in cases with resultant transudative pleural effusions, large vein bypass graft surgery may be an effective method of central venous decompression. This case reports the excellent response to surgical therapy in relieving symptoms, and preventing recurrence, of pleural effusions secondary to the SVC syndrome.
SVC syndrome resulting from fibrosing mediastinitis is a relatively uncommon cause of transudative pleural effusions. Venous bypass surgery may be a very effective form of symptomatic treatment.
S.M. Caples, None.