Superior vena cava syndrome (SVCS)By mahyar
History: 48 Y/O Male with dyspnea
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Superior vena cava syndrome (SVCS) is obstruction of blood flow through the superior vena cava (SVC). It is a medical emergency and most often manifests in patients with a malignant disease process within the thorax. A patient with superior vena cava syndrome (SVCS) requires immediate diagnostic evaluation and therapy.
William Hunter first described the syndrome in 1757 in a patient with syphilitic aortic aneurysm. In 1954, Schechter reviewed 274 well-documented cases of superior vena cava syndrome (SVCS) reported in the literature; 40% of them were due to syphilitic aneurysms or tuberculous mediastinitis. In more recent times, these infections have gradually decreased as the primary cause of superior vena cava (SVC) obstruction. Lung cancer, particularly adenocarcinoma, is now the underlying process in approximately 70% of the patients with superior vena cava syndrome (SVCS). However, up to 40% of the causes are due to nonmalignant causes.
The superior vena cava (SVC) is the major drainage vessel for venous blood from the head, neck, upper extremities, and upper thorax. It is located in the middle mediastinum and is surrounded by relatively rigid structures such as the sternum, trachea, right bronchus, aorta, pulmonary artery, and the perihilar and paratracheal lymph nodes. It extends from the junction of the right and left innominate veins to the right atrium, a distance of 6-8 cm. It is a thin-walled, low-pressure, vascular structure. This wall is easily compressed as it traverses the right side of the mediastinum.
Obstruction of the superior vena cava (SVC) may be caused by neoplastic invasion of the venous wall associated with intravascular thrombosis or, more simply, by extrinsic pressure of a tumor mass against the relatively fixed thin-walled superior vena cava (SVC). Postmortem examinations reveal that complete superior vena cava (SVC) obstruction is the result of intravascular thrombosis in combination with extrinsic pressure. Incomplete superior vena cava (SVC) obstruction is more often secondary to extrinsic compression without thrombosis. Other causes include compression by intravascular arterial devices. The incidence is on the rise in line with the increased usage of endovascular devices.
An obstructed superior vena cava (SVC) initiates collateral venous return to the heart from the upper half of the body through 4 principal pathways. The first and most important pathway is the azygous venous system, which includes the azygous vein, the hemiazygous vein, and the connecting intercostal veins. The second pathway is the internal mammary venous system plus tributaries and secondary communications to the superior and inferior epigastric veins. The long thoracic venous system, with its connections to the femoral veins and vertebral veins, provides the third and fourth collateral routes, respectively.
Despite these collateral pathways, venous pressure is almost always elevated in the upper compartment if obstruction of the superior vena cava (SVC) is present. Venous pressure as high as 200-500 cm H2 O has been recorded in patients with severe superior vena cava syndrome (SVCS).
Superior vena cava syndrome (SVCS) develops in 5-10% of patients with a right-sided malignant intrathoracic mass lesion. In 1969, Salsali and Cliffton observed superior vena cava syndrome (SVCS) in 4.2% of 4960 patients with lung cancer; 80% of the tumors inducing superior vena cava syndrome (SVCS) were of the right lung. In 5 large series of small cell lung cancer, 9-19% of patients demonstrated superior vena cava syndrome (SVCS). In 1987, Armstrong and Perez found superior vena cava syndrome (SVCS) in 1.9% of 952 patients with lymphoma.
1. Survival in patients with superior vena cava syndrome (SVCS) depends mainly on the course of the underlying disease. No mortality, per se, results directly from mild venous congestion.
2. In patients with benign superior vena cava syndrome (SVCS), life expectancy is unchanged.
3. If superior vena cava syndrome (SVCS) is secondary to a malignant process, patient survival correlates with the histology of the tumor. Patients with signs and symptoms of laryngeal and cerebral edema have the most life-threatening manifestations of this syndrome and are in danger of sudden death. Clinical observations show that approximately 10% of patients with a bronchogenic carcinoma and 45% of patients with lymphoma treated with irradiation live at least 30 months. In contrast, patients with untreated malignant superior vena cava syndrome (SVCS) survive only approximately 30 days.
The frequency of superior vena cava syndrome (SVCS) in different races depends largely on the frequency of lung cancer and lymphomas in these populations.
1. Malignant causes of superior vena cava syndrome (SVCS) are most commonly observed in males because of the high incidence of lung cancer in this population.
2. In contrast, no sex difference is observed in cases related to benign causes.
1. Malignant causes of superior vena cava syndrome (SVCS) are predominantly observed in individuals aged 40-60 years.
2. Benign causes account for most of the cases diagnosed in individuals aged 30-40 years.
3. Obstruction of the superior vena cava (SVC) in the pediatric age group is rare and has a different etiologic spectrum.
1. Early in the clinical course, partial superior vena cava (SVC) obstruction may be asymptomatic, but more often, minor symptoms and signs are overlooked.
2. As the syndrome advances toward total superior vena cava (SVC) obstruction, the classic symptoms and signs become more obvious.
1. Dyspnea is the most common symptom and is observed in 63% of patients with superior vena cava syndrome (SVCS).
2. Other symptoms include facial swelling, head fullness, cough, arm swelling, chest pain, dysphagia, orthopnea, distorted vision, hoarseness, stridor, headache, nasal stuffiness, nausea, pleural effusions, and light-headedness.
1. The characteristic physical findings of superior vena cava syndrome (SVCS) include venous distension of the neck and chest wall, facial edema, upper extremity edema, mental changes, plethora, cyanosis, papilledema, stupor, and even coma.
2. Bending forward or lying down may aggravate the symptoms and signs.
1. More than 80% of cases of superior vena cava syndrome (SVCS) are caused by malignant mediastinal tumors.
1. Bronchogenic carcinomas account for 75-80% of all these cases, with most of these being small-cell carcinomas.
2. Non-Hodgkin lymphoma (especially the large cell type) represents 10-15% of cases.
2. Causes of superior vena cava syndrome (SVCS) appear similar to the relative incidence of primary lung and mediastinal tumors.
3. Rare malignant diagnoses include Hodgkin disease, metastatic cancers, primary leiomyosarcomas of the mediastinal vessels, and plasmocytomas.
4. Nonmalignant conditions causing superior vena cava syndrome (SVCS) include mediastinal fibrosis; vascular diseases such as aortic aneurysm, vasculitis, and arteriovenous fistulas; infections such as histoplasmosis, tuberculosis, syphilis, and actinomycosis; benign mediastinal tumors such as teratoma, cystic hygroma, thymoma, and dermoid cyst; cardiac causes, such as pericarditis and atrial myxoma; and thrombosis related to the presence of central vein catheters. These account for approximately 22% of the causes of superior vena cava syndrome (SVCS)
1. Patients presenting with overt superior vena cava syndrome (SVCS) may be diagnosed by means of physical examination alone. However, subtle presentations require diagnostic imaging. Chest radiography may reveal a widened mediastinum or a mass in the right side of the chest. Only 16% of the patients studied by Parish and colleagues in 1981 had normal findings on chest radiography.
2. CT has the advantage of providing more accurate information on the location of the obstruction and may guide attempts at biopsy by mediastinoscopy, bronchoscopy, or percutaneous fine-needle aspiration.
I. It also provides information on other critical structures such as the bronchi and the vocal cords.
II. The additional information is necessary because the involvement of these structures requires prompt action for relief of pressure.
3. MRI has not been sufficiently investigated, but it appears promising.
I. It has several potential advantages over CT scanning, including the fact that it provides images in several planes of view and allows direct visualization of blood flow. Furthermore, MRI does not require iodinated contrast material. This is especially important when stenting is anticipated.
II. Disadvantages may include increased scanning time with attendant problems in patient compliance and increased cost.
4. Invasive contrast venography is the most conclusive diagnostic tool.
I. It precisely defines the etiology of obstruction.
II. It is especially important if surgical management is being considered for the obstructed vena cava.
5. Radionuclide technetium-99m venography is an alternative minimally invasive method of imaging the venous system. Although images obtained by this method are not as well defined as those achieved with contrast venography, they demonstrate potency and flow patterns.
6. Gallium single-proton emission CT scanning may be of value in select cases.
1. Most patients with superior vena cava syndrome (SVCS) present before the primary diagnosis is established.
2. Controversy often arises in the treatment of a patient with superior vena cava syndrome (SVCS) in regard to the need for pathologic confirmation of malignancy before the start of therapy.
3. Treatment without an established diagnosis should be initiated only in patients with rapidly progressive symptoms or those in whom multiple attempts to obtain a tissue diagnosis have been unsuccessful.
4. Fortunately, relatively noninvasive measures establish the diagnosis in a high percentage of patients with superior vena cava syndrome (SVCS).
1. Sputum cytologic results are diagnostic in 68% of the cases, whereas biopsy of a palpable supraclavicular node is positive in 87%.
2. Bronchoscopy has a 60% success rate, while thoracotomy is 100% successful.
3. Open biopsy is rarely needed for diagnosis. Dosios et al showed that cervical mediastinoscopy and anterior mediastinoscopy are effective in establishing a histiologic diagnosis
Differential diagnosis: Lung cancer, particularly adenocarcinoma, is now the underlying process in approximately 70% of the patients with superior vena cava syndrome (SVCS). However, up to 40% of the causes are due to nonmalignant causes
Diagnosis confirmation: Surgery / Histo
Region / Organ: Thorax-Vessels
Todd A Nickloes, DO, et al, Superior Vena Cava Syndrom, emedicine.medscape
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