Superior Vena Cava Syndrome
Superior vena cava syndrome (SVCS) is a group of symptoms that can occur in people who have lung cancer, lymphoma, or other cancers that involve the center of the chest. It also can occur from noncancer causes. SVCS is serious when it occurs in adults. It is life-threatening in children.
SVCS is caused by the partial blockage of the superior vena cava. This is the vein that carries blood from the head, neck, chest, and arms to the heart. SVCS may cause these symptoms:
- Trouble breathing
- Rapid breathing
- Swelling of the face, neck, upper body, and arms
In rare cases, people may have these signs or symptoms:
- Chest pain
- Trouble swallowing
- Coughing up blood
- Bluish color to the skin from cyanosis (a lack of oxygen in the blood)
- Horner's syndrome (constricted pupil, drooping eyelid, and no sweating on one side of the face)
- Paralyzed vocal cord
SVCS is usually a sign of locally advanced lung cancer. Survival depends on the status of the patient's disease.
SVCS is most often caused by cancer, specifically lung cancer and lymphoma. A rare cause of SVCS is an infection of the mediastinum (in the chest). This infection causes thickening and hardness of the mediastinal tissues. Other rare causes of SVCS are:
- Germ cell tumors
- Metastatic breast cancer
- Colon cancer
- Kaposi sarcoma
- Cancer of the esophagus
- Behcet's syndrome (a disease of the immune system)
- Thymus tumor
- Thyroid tumor
- Sarcoidosis (a rare inflammatory disease that causes lumps to form in body organs, most often the lungs)
- Blood clot in the vein caused by an intravenous catheter or pacemaker wire
The major veins connected to the right atrium (a chamber of the heart) are the superior vena cava and the inferior vena cava. The superior vena cava returns blood from the upper body to the heart. The inferior vena cava returns the blood from the lower part of the body. The superior vena cava is thin-walled, and the blood is under low pressure. It lies near lymph nodes in the chest. So when the lymph nodes or the aorta of the heart get bigger, the superior vena cava is squeezed, blood flow slows, and blockage may occur.
The speed of the blockage and its location determine the seriousness of the syndrome. The more rapidly the block occurs, the more severe the symptoms. The other veins do not have time to widen to adjust to the increased blood flow. If the blockage occurs above where the superior vena cava and inferior vena cava meet, the syndrome is less obvious. The veins can swell more easily and handle the increased blood flow. If the blockage occurs below this point, more symptoms are seen. That's because the blood must be returned to the heart by the veins in the upper abdomen and the inferior vena cava, which requires higher pressure.
Sometimes, the other veins can take over for the superior vena cava if it is blocked. But this takes time.
Once SVCS is diagnosed, prompt care is important.
As long as the trachea (windpipe) is not blocked, SVCS is not usually a life-threatening emergency. So a definite diagnosis should be made before treatment is started. These tests may be used to find out the site and type of blockage:
- Chest X-ray
- CT scan of the chest
- Venography (imaging of the veins)
- Ultrasound (high energy sound waves used to make a picture)
If cancer is suspected, a biopsy will be needed. The results of the biopsy will help the healthcare provider decide on the best treatment.
Treatment of SVCS depends on the cause of the blockage, the seriousness of the symptoms, the prognosis of the patient, and the patient's preferences. Radiation therapy and chemotherapy should not be started until the cause of the blockage is determined. The treatments discussed below focus on a superior vena cava blockage caused by cancer. Since the treatment of the blockage may depend on the type of cancer, this diagnosis should be made before treatment is started. Unless the airway is blocked or the brain is swelling, waiting to start treatment usually isn't a problem. The following treatments can be used for SVCS:
A patient with good blood flow through other veins and few symptoms may not need treatment. But he or she will be closely monitored for new symptoms or changes. In many cases, SVCS is managed by treating the cancer that is causing the blockage. If the blockage is above the area where the superior and inferior vena cava veins join, and other veins are able to take over for the superior vena cava, the symptoms may stabilize and the patient may be comfortable enough to not need more therapy. Short-term relief for someone who has symptoms, but who does not want aggressive treatment, may include:
- Raising the head
- Using corticosteroids (medicines that decrease swelling)
- Increasing the removal of fluids with medicines such as diuretics. Diuretics may help symptoms of swelling. But they can cause problems such as dehydration.
If the blockage of the superior vena cava is caused by a tumor that is not sensitive to chemotherapy, radiation therapy may be given.
Chemotherapy is the treatment of choice for sensitive tumors such as lymphoma or small cell lung cancer. The presence of SVCS should not change the treatment approach.
Thrombolysis (breaking up blood clots)
SVCS may come about when a thrombus (blood clot) forms. People who have blood clots may need treatment to dissolve or remove the blood clot.
A stent may be used to open up the blocked vein. A stent is a tube-like device that is put into the blocked part of a vein to allow blood to pass through. Sometimes, patients may also receive an anticoagulant to prevent more blood clots from forming.
Surgical bypass of a blocked superior vena cava is used more often for patients without cancer. But it is used sometimes for cancer patients with blockages caused by cancer.
Patients and family members are often frightened and anxious because of the symptoms of SVCS, mainly swelling, trouble swallowing, coughing, and hoarseness. Patients and their families should receive information about the cause of symptoms and their short-term treatment. When aggressive treatment is deferred because of terminal cancer, patients and family members can be taught to treat symptoms.
Because most adult who develop SVCS have lung cancer, the type of treatment and care prescribed should take into account the person's prognosis and other symptoms caused by the cancer.
Superior vena cava syndrome occurring in children
SVCS refers to blockage of the superior vena cava, while the squeezing of the trachea (windpipe) is called superior mediastinal syndrome. Since superior mediastinal syndrome and the resulting breathing problems often occur in children with SVCS, the 2 syndromes are considered to be the same in children. In adults, the windpipe is fairly rigid. But in children, it is softer and more likely to be squeezed shut. Also, the diameter of a child's windpipe is smaller. So any amount of swelling can cause breathing problems. SVCS in children is different from the syndrome in adults. It is a serious medical emergency.
The most common symptoms in children are like those in adults. They include:
- Trouble breathing
- Chest pain
- Vision problems
- Sense of fullness in the ears
SVCS is rare in children. The cause, diagnosis, and treatment of SVCS in children is not the same as it is in adults. The most common cause of SVCS in children is non-Hodgkin's lymphoma. As with adults, a possible noncancerous cause is a blood clot from an intravenous catheter.
The diagnosis in children is often made with a physical exam, medical history, and chest X-ray. If lymphoma or another cancer is suspected, a biopsy is needed.
When cancer is the cause of SVCS, the situation may be a medical emergency, with no time to diagnose the cancer with tissue. In some cases, the best approach is to start treatment before a definite diagnosis is made. Radiation therapy is usually used to treat the tumor. Once the condition is stabilized, a biopsy may be safer.
Along with radiation, chemotherapy and steroids may be used. If the tumor does not respond, it may not be cancerous. If needed, surgery may be done. Surgery may include a bypass to go around the blocked part of the vein. A stent may also be placed to open the vein.