Sections View Full Chapter Figures Tables Videos Annotate Full Chapter Figures Tables Videos Supplementary Content + Download Section PDF Listen ++ For further information, see CMDT Part 12-16: Superior Vena Caval Obstruction + Key Features Download Section PDF Listen +++ ++ A rare disorder caused by partial or complete obstruction of the superior vena cava Most frequent causes Neoplasms, such as lymphomas, primary malignant mediastinal tumors, or carcinoma of the lung with direct extension (over 80%) Chronic fibrotic mediastinitis, either of unknown origin or secondary to tuberculosis, histoplasmosis, pyogenic infections, or drugs (especially methysergide) Deep venous thrombosis Aneurysm of the aortic arch Constrictive pericarditis + Clinical Findings Download Section PDF Listen +++ ++ Swelling of the neck and face and upper extremities Headache Dizziness, stupor, syncope Visual disturbances Bending over or lying down accentuates symptoms Dilated anterior chest wall veins and/or collateral veins Facial flushing Brawny edema and cyanosis of the face, neck, and arms Cerebral and laryngeal edema Venous pressure Elevated in the arm (often > 20 cm H2O) Normal in the leg + Diagnosis Download Section PDF Listen +++ ++ Venous pressure Elevated (often more than 20 cm H2O) in the arm Normal in the leg Bronchoscopy is often performed, since lung cancer is a common cause Transbronchial biopsy is relatively contraindicated because of venous hypertension and the risk of bleeding Chest radiographs and a CT scan will define the location and often the nature of the obstructive process Contrast venography or magnetic resonance venography (MRV) will map out the extent and degree of the venous obstruction and the collateral circulation Brachial venography or radionuclide scanning following intravenous injection of technetium Tc-99m pertechnetate demonstrates a block to the flow of contrast material into the right heart and enlarged collateral veins These techniques also allow estimation of blood flow around the occlusion as well as serial evaluation of the response to therapy. + Treatment Download Section PDF Listen +++ ++ Conservative measures such as elevation of the head of the bed and lifestyle modification to avoid bending over are useful Occasionally, anticoagulation is needed, while thrombolysis is rarely needed Balloon angioplasty of the obstructed caval segment combined with stent placement Procedure of choice Provides prompt relief of symptoms Urgent treatment for neoplasm consists of Cautious use of intravenous diuretics Mediastinal irradiation Chemotherapy added for lymphoma or small-cell carcinoma In cases where the thrombosis is secondary to an indwelling catheter, thrombolysis may be attempted