Superior vena cava syndrome overview
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Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]Associate Editor(s)-in-Chief: Maria Fernanda Villarreal, M.D. [2]
Overview
Superior vena cava (SVC) syndrome arises from the obstruction of venous blood drainage of the superior vena cava, which is normally is involved in the major blood flow return from head, neck, upper extremities, and upper thorax to the heart. Superior vena cava syndrome is a complication from a partial or complete obstruction due to malignant causes (60%) or benign causes (20%). This syndrome may be caused by the invasion of the venous wall associated with intravascular thrombosis, enlarged nodes, enlarged ascending aorta, or more simply, by extrinsic pressure of a tumor mass against the thin-walled superior vena cava (SVC) which leads to the development of SVC syndrome. SVC syndrome is associated with a number of conditions that include malignant tumors, tuberculosis, histoplasmosis, and syphilis.[1]
Historical Perspective
Superior vena cava syndrome was first discovered by William Hunter (1718-1783), a Scottish obstetrician, in 1757 following as a complication of a syphilitic aortic aneurysm. [2]
Pathophysiology
The superior vena cava (SVC) is the major blood vessel for drainage of venous blood from the head, neck, upper extremities, and upper thorax to the heart. Obstruction of the superior vena cava (SVC) may be caused by neoplastic invasion of the venous wall associated with intravascular thrombosis, enlarged nodes, enlarged ascending aorta, or more simply, by extrinsic pressure of a tumor mass against the thin-walled superior vena cava (SVC) which leads to the development of SVC syndrome.
Causes
Superior vena cava syndrome may be caused by obstruction of the superior vena cava (SVC) by neoplastic invasion of the venous wall associated with intravascular thrombosis, enlarged nodes, enlarged ascending aorta, or more simply, by extrinsic pressure of a tumor mass against the thin-walled superior vena cava (SVC).
Differentiating Superior Vena Cava Syndrome from other Diseases
Superior vena cava syndrome should be differentiated from other causes of dyspnea and jugular venous distention, such as, cardiac tamponade, chronic obstructive pulmonary disease, mediastinitis, pneumonia, acute respiratory distress syndrome, syphilis, and tuberculosis.
Epidemiology and Demographics
Most SVC syndromes in the present day are related to malignancy. An underlying malignancy is found in approximately 90% of patients.
Natural History, Complications and Prognosis
Complications of superior vena cava syndrome include airway obstruction and increased ICP. The prognosis will vary depending on the cause of the syndrome, and the amount of blockage that has already occurred.
Diagnosis
History and Symptoms
SVC syndrome usually presents more gradually with an increase in symptoms over time as malignancies increase in size or invasiveness.[3] Symptoms occur when something blocks the blood flowing back to the heart. They may begin suddenly or gradually, and may worsen when you bend over or lie down. The most common symptoms are shortness of breath (dyspnea) and swelling of the face, neck, trunk, and arms.
Physical Examination
Physical examination findings include swelling and redness of the face, bluish coloration to the skin over time, visibly distended veins, drooping of the eyelid, and swelling around the eye.
Chest X Ray
Blockage of the SVC may be visible on chest x ray and it is also useful to detect lung cancer.
CT
Blockage of the SVC may be visible precisely on CT scan of the chest and it is also useful in evaluating source and extent of a neoplasm.
MRI
Blockage of the SVC may be visible precisely on MRI of the chest and it is also useful in evaluating source and extent of a neoplasm.
Ultrasound
Doppler ultrasound may be valuable in assessing the site and nature of the obstruction in SVC syndrome. Venous patency and the presence of thrombi can also be assessed by using contrast and rapid scanning techniques.
Other Imaging Findings
SVC syndrome may also affect the findings of radionuclide ventriculography and liver scan.
Treatment
Medical Therapy
The treatment of SVC syndrome depends on the etiology of the obstruction, the severity of the symptoms, the prognosis of the patient, and patient preferences and goals for therapy.
Surgery
Surgical options include stent placement and surgical bypass.
Radiation Therapy
If the obstruction of the SVC is caused by a tumor that is not sensitive to chemotherapy, radiation therapy should be given. Treatment with larger fractions of radiation is thought to be beneficial in developing a rapid response. One study shows, however, that there is no obvious need for large radiation fraction sizes for the first few radiation treatments as was previously believed. Many fractionation schemes have been used, with doses ranging from 30 Gy in 10 fractions to 50 Gy in 25 fractions. Relief of symptoms in small cell lung cancer is reported to be 62% to 80%, whereas in non-small cell lung cancer, approximately 46% of the patients experienced symptomatic relief. In one study, more than 90% of the patients achieved a partial or complete response with a 3-week regimen of 8 Gy given once a week for a total dose of 24 Gy.
Primary Prevention
Prompt treatment of other medical disorders may reduce the risk of developing SVC obstruction.
References
- ↑ Menon A, Gupta A (2015). "Superior vena cava syndrome". Indian J. Med. Res. 142 (3): 350. doi:10.4103/0971-5916.166606. PMC 4669875. PMID 26458355.
- ↑ William Hunter. https://en.wikipedia.org/wiki/William_Hunter_%28anatomist%29 Accessed on December 11, 2016
- ↑ Beeson, Michael S. "Superior Vena Cava Syndrome". Retrieved 2008-03-24.
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