Superior vena cava syndrome is characterized by disruption of blood flow from the arms and head portions to the heart. Anything like a blood clot or thrombus or compression on the vein can cause this disruption. There is a large vein present in the chest for collecting impure blood from the head, arms and other upper part of the body to the right atrium. When there is disruption in the blood flow to the heart, the blood stays back in these regions causing edema or swelling in face and arms, this condition is called as superior vena cava syndrome.
Abnormalities in heart, trachea, esophagus and big blood vessels can cause compression on the veins causing this syndrome. This condition is a medical emergency and needs immediate treatment.
Cancer can cause superior vena cava syndrome. Any type of cancer like lymphoma, metastatic cancer can compress the veins of superior vena cava. Tumors, blood clots and thrombus in the mediastinum can cause compression. It can occur as a side effect of pacemaker wiring or dialysis procedure and usage of intravenous catheters. Performing invasive procedure on the individual often increases the risk of developing SVCS.
It can occur due to infectious diseases like syphilis or lupus or tuberculosis and due to sarcoidosis. It is reported that mediastinal tumor is the major contributing factor (more than 80%) for SVCS. Bronchial cancer is the next factor that affects superior vena cava. Very less case (10-15%) are caused due to Non Hodgkin lymphoma. In rare cases, superior vena cava syndrome can develop due to aortic aneurysm, fistulas in the artery or veins, cystic hygroma or dermoid cyst and pericarditis.
The signs of SVCS do not show immediately it develops rather slowly. Some of the symptoms of mild compression on the superior vena cava are shortness of breath, swelling or edema (building up of fluids) on face and arms. In the condition of blood not getting back to the heart, it becomes difficult for the heart to pump fresh oxygenated blood for meeting the demands of metabolism. Chest pain, hoarseness, shortness of breath and dilation of veins in the skin are less common symptoms. One should not bend forward or lie down having these symptoms since it will make the condition worse.
Your doctor will order for chest X-ray to detect enlargement of mediastinum, ultrasound scan for checking the blood clots and CT scan for diagnosing superior vena cava syndrome. In rare cases, a biopsy is done by taking small tissue sample to test for tumor.
Your doctor will identify the exact cause of the disruption of blood flow before giving treatment. He will check the health condition of the patient, his symptoms to decide on the course of treatment. If the causative factor is tumor or cancer on the superior vena cava then depending on the intensity of tumor, your doctor will first wait for change in symptoms. Unless the airway is completely blocked due to tumor, surgery will not be done.
Your doctor will closely monitor the symptoms and treat the cancer that causes the compression. In most of the cases, if the underlying cancer is treated, SVCS symptoms will disappear. The patient will be asked to keep his head in elevated position and medications like corticosteroids are given for reducing swelling. Diuretics are injected intravenously for eliminating the accumulated fluids inside the vein. These are temporary methods of treating SVCS caused due to cancer.
Chemotherapy and radiation therapy are given in combined form for shrinking the cancer cells like lymphoma. In case of blood clots, thrombolysis is done for dissolving the blood clots easily. For some patients, a stent is placed to open the blocked vein to facilitate easy flow of blood. Anticoagulants like warfarin are given to prevent blood clotting. Stenting provides great relief from the symptoms for many patients. Bypass surgery is done for patients without cancer for clearing the blockage in superior vena cava vein. Very often surgery is done for patients without any trace of cancer.
Some doctors believe the thumb rule of ABC for treating SVCS :-
A stands for maintaining or clearing the airway.
B stands for giving supplemental oxygen for breathing.
C stands for maintaining circulation of blood in the heart.