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Superior Vena Cava Syndrome

Superior Vena Cava Syndrome

1. SVC Obstruction and Collateral

A. Obstruction below azygous vein
1) Azygous - hemiazygous, lumbar veins to IVC
B. Obstruction above azygous vein
1) Venous collateral in neck to azygous to SVC
C. Obstruction includes azygous vein
1) Internal mammary, paraspinous, esophageal and subcutaneous vein to IVC
D. Cerebral decompression through a single jugular vein via midline intracranial venous sinuses

2. Pathogenesis

A. Extrinsic compression of SVC
1) Gradual SVC obstruction
B. Invasion of SVC
1) Obstruction develops rapidly
C. Thrombosis of SVC
1) Acute obstruction
D. Venous hypertension and lymphatic obstruction - all empty into the subclavian veins

3. Causes

A. Benign 10%
1) Inflammatory - histoplasmosis, idiopathic fibrosing mediastinitis
2) Iatrogenic - pacemaker electrode, hyperalimentation or other CV line
B. Malignant 90%
1) Bronchogenic, epidermoid 65-80%
2) Small cell 12-30%
3) Lymphoma 12-20%

4. Symptoms and Signs

A. Swelling face, neck, arms
B. Shortness of breath, orthopnea, cough and chest pain suggest upper airway obstruction
C. Hoarseness, stridor, tongue swelling, nasal congestion
D. Headaches, syncope and lethargy are caused by cerebral edema from venous hypertension
E. Symptoms worse lying down, bending forward
F. Symptoms of cerebral or laryngeal edema is associated witha reduced life expectancy of about 6 weeks, demanding urgent intervention
G. Caval obstruction may be the life-limiting problem of patients with underlying malignancy

5. Diagnosis

A. Chest x-ray
1) Right hilar mass - bronchogenic carcinoma
2) Anterior mediastinal mass - lymphoma
3) Calcification - histoplasmosis
B. Simultaneous bilateral arm venogram
1) Defines obstruction and collateral circulation
2) Identifies thrombus
C. Computerized axial tomography
1) Assessment of mediastinum
2) Determine patency of jugular veins
3) Directed needle biopsy

6. Radiation Therapy

A. Since most cases due to malignancy, nearly all patients receive radiation
B. 80-90% relieved of SVC Syndrome
C. 50% of patients relapse
D. Relapse occurs in benign disease as well; although collaterals develop, thrombosis will continue to propogate and occlude these collaterals over time

7. Medical Therapy

A. Chemotherapy for lymphomas and small cell carcinoma
B. Diuretics and corticosteroids reduce cerebral edema
C. Anticoagulants in selected cases to prevent clot propagation
D. Thrombolytic therapy for selected acute thrombosis

8. Surgery

A. Severe SVC Syndrome associated with thrombosis of caval tributaries and inadequate collateral circulation
B. SVC bypass with composite autogenous vein grafts or PTFE 6-12 months after onset in benign causes or for palliation in malignant causes with severe or acute onset SVC syndrome