Superior vena caval (SVC) obstruction is usually due to compression or invasion by tumor, with or without secondary thrombus formation.
Primary lung cancer accounts for two-thirds of cases, but it can occur with any tumor involving the mediastinum. Less commonly, thrombosis occurs secondary to a centrally placed catheter. Occasionally, there is a benign cause such as fibrosis caused by previous mediastinal irradiation.

The common presenting symptoms are dyspnea, facial swelling, and a feeling of fullness in the head. There may be other symptoms related to mediastinal disease, including cough, dysphagia, chest pain, or hoarseness. Neurological symptoms include headache, dizziness, blurred vision, and syncope, all of which are aggravated or precipitated by leaning forward or stooping. Examination shows venous distention in the neck and on the chest wall; there are dilated veins on the backs of the hands that do not collapse when the arm is elevated. There is edema of the face, neck, and upper limbs as well as conjunctival edema and retinal vein dilatation. The diagnosis can usually be made on clinical grounds. A CT scan should be performed to determine the cause and location of the obstruction.

SVCS is a medical emergency that requires immediate diagnostic evaluation and therapy.
In the management of SVCS the goals are to relieve symptoms and to attempt cure of the primary malignant process.
Patients with clinical SVCS often gain significant symptomatic improvement from conservative treatment measures, including elevation of the head of the bed and supplemental oxygen. Emergency treatment is indicated when brain edema, decreased cardiac output, or upper airway edema is present. Corticosteroids and diuretics are often used to relieve laryngeal or cerebral edema.

Radiotherapy has been advocated as a standard treatment for most patients with SVCS: it is used as the initial treatment if a histologic diagnosis cannot be established and the clinical status of the patient is deteriorating.

Chemotherapy may be preferable to radiation for patients with chemosensitive tumors.

Surgical bypass of the SVC may be a useful way to palliate symptoms in carefully selected patients with SVCS.

The principal options for endovascular therapy today are stenting, percutaneous transluminal angioplasty, thrombolysis, or some combination thereof. In most patients with SVCS, stenting of the SVC provides rapid symptomatic relief within a few days.

See reference for more information.

Woodruff R. Palliative medicine evidence-based symptomatic and supportive care for patients with advanced cancer. 4th ed. Oxford University Press, 2004. p. 304.

Adapted from Medscape Drugs & Diseases. Superior Vena Cava Syndrome. Available at http://emedicine.medscape.com/article/460865-overview. Accessed on July 14, 2017. To view the entire article and all other content on the Medscape Drugs & Diseases site, a free, one-time registration is required.