Pathogenesis of superior vena cava syndrome

By | April 9, 2012

Superior vena cava syndrome refers to the superior vena cava and its branches stenosis or obstruction, causing head and neck swelling, cyanosis, chest wall, venous engorgement, and dyspnea, one for cancer of the common emergency should normally be dealt with expeditiously to alleviate the symptoms. Because of effective antibiotic treatment, so the superior vena cava syndrome caused by a benign reason for less, but should pay attention to the identification of mediastinal tuberculosis.
Superior vena cava syndrome, pathogenesis and diagnosis
Superior vena cava syndrome usually occurs as the latent nature, then there are special symptoms and signs, it is the basis of the pathophysiology of venous drainage and the upper thoracic obstruction.Superior vena cava is the main vein pipeline, bringing together head, neck, upper limbs, chest, regurgitation of blood into the right atrium, with the increasing pressure on the vena cava, collateral veins, superficial vein dilation, there may be facial congestion, conjunctival edema and various neurological symptoms such as headaches, visual disturbances and altered consciousness. Neurological symptoms can be secondary to superior vena cava obstruction caused by increased intracranial pressure caused by or aggravated.
The reason why the superior vena cava obstruction more easily because of its thin wall, low pressure. Because the superior vena cava in the mediastinum is fixed right in front of, behind the breastbone near the right main bronchus and the ascending aorta, completely surrounded by lymph node chain – the superior vena cava in front of mediastinal lymph nodes, followed by the right or paratracheal lymph nodes – the main branches of azygos vein can easily be enlarged paratracheal lymph node compression, depending on clinical symptoms and the degree of venous compression speed. If not treated, the symptoms must continue to develop superior vena cava obstruction often leads to irreversible long-term vein thrombosis, central nervous system damage and pulmonary complications.
Superior vena cava syndrome, clinical diagnosis is relatively easy expansion of the superior vena cava appears to have diagnostic significance is the signs. Associated with hilar lymphadenopathy or lung disease accounts for about 50%, 20% – 25% may be associated with pleural effusion (mostly right). X-ray examination to determine the primary lesion of help, usually in the mediastinum (right lateral lobe 75%) showed the tumor.
Pathogenesis of superior vena cava syndrome, sputum cytology, lymph node biopsy and bone marrow examination helps to confirm the diagnosis. CT examination of mediastinal lymph nodes, but not significantly superior vena cava syndrome were useful. Bronchoscopy, esophageal examination, mediastinal examination, scalene lymph node biopsy and / or thoracic surgical exploration histopathological diagnosis can be made, but there is a certain risk, should be used with caution. Where there is no history of primary tumor, pulmonary lesions can not see, should pay attention to differential diagnosis, rule out the rare, but important benign lesions, such as tuberculosis, thrombus formation, while actively symptomatic treatment for the cause of creating the necessary examination conditions.

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