SUPERIOR VENA CAVA SYNDROME:

Obstruction of the superior vena cava produces a distinctive clinical syndrome. Over 90% of patients have obstruction from a malignant process. The most common neoplasm is a bronchogenic carcinoma invading the mediastinum. Less commonly include thymoma or lymphoma. Benign causes are infrequent but can be produced by granulomatous disease, aortic aneurysm, and central venous catheters.

Pathophysiology:

With obstruction of the SVC there is an increase in venous pressure. The degree to which is influenced by the rate of development and site of obstruction. Collateral circulations are formed to provide venous decompression. Five major routes of collateral flow are as follows: 1) azygos/hemiazygos, 2) internal thoracic, 3) lateral thoracic and thoracoepigastric, 4) paravertebral, 5) anterior jugular venous system.

Acute obstruction of the vena cava can produce fatal cerebral edema within minutes. The other extreme is if the obstruction develops slowly collateral circulation has time to develop and symptoms are mild.

Symptoms:

With mild obstruction, symptoms include headache, swelling of the eyes, face and neck. Symptoms may be aggravated by positional changes. Edema of the vocal cords can produce hoarseness. Pulmonary symptoms of cough and hemoptysis are also present.

Diagnostic Studies:

Computed tomography is frequently used to evaluate patients as it can show the site and degree of obstruction. Other advantages are the ability to reliably depict an etiology. Venography also outlines the location and extent of obstruction.

Treatment:

With a malignant process, involvement of the SVC precludes surgical intervention. The standard therapy is intensive radiation with or without chemotherapy. With radiation, most patients have improvement in symptoms within two weeks. Death however is virtually inevitable within several months.