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Superior Vena Cava Syndrome

Superior vena cava syndrome (SVCS) is a collection of symptoms that usually occur in patients who have lung cancer, non-Hodgkin lymphoma, or other cancers. It also can occur from noncancer causes. Although serious when it occurs in adults, this syndrome is life-threatening in children. This brief summary describes superior vena cava syndrome and its treatment.

Overview

Superior vena cava syndrome is caused by the partial blockage of the superior vena cava, which is the vein that carries blood from the head, neck, chest, and arms to the heart. Symptoms that may indicate this syndrome include difficulty breathing, coughing, and swelling of the face, neck, upper body, and arms. In rare occasions, patients may complain of hoarseness, chest pain, difficulty swallowing, and coughing up blood. Physical signs of SVCS include swelling of neck or chest veins, collection of fluid in the face or arms, and rapid breathing. Rarely, cyanosis (lack of oxygen in the blood causing a bluish color to the skin), Horner's syndrome (constricted pupil, drooping eyelid, and no sweating on one side of the face), and a paralyzed vocal cord may also be present.

SVCS is usually a sign of locally advanced lung cancer. Survival depends on the status of the patient's disease.

Causes

Most superior vena cava syndrome cases are attributed to cancer, with the most common causes being lung cancer and non-Hodgkin lymphoma. A rare cause of superior vena cava syndrome is an infection of the mediastinum (in the chest), which causes thickening and hardness of the mediastinal tissues. Other rare causes of superior vena cava syndrome include metastatic 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, Hodgkin's disease, and sarcoidosis (a rare inflammatory disease that causes lumps to form in body organs, most often the lungs). Another rare cause is a blood clot in the vein either 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, and 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. Therefore, when the lymph nodes or the aorta of the heart get bigger, the superior vena cava is squeezed, blood flow slows, and complete blockage may occur.

The speed of the blockage and its location determine the seriousness of the syndrome. The more rapidly the obstruction occurs, the more severe the symptoms, since 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, since the veins can swell more easily and handle the increased blood flow. If the blockage occurs below this point, more symptoms are seen, since 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 obstructed, but this takes time.

Diagnosis

Once superior vena cava syndrome is recognized, prompt attention is important.

As long as the trachea (windpipe) is not blocked, superior vena cava syndrome is not usually a life-threatening emergency; therefore, a definite diagnosis should be made before treatment is begun.

A chest X-ray, computed tomography (CT) scanning of the chest, venography (imaging of the veins), magnetic resonance imaging (MRI), and ultrasound (high energy sound waves used to develop a picture) may all be used in determining the site and type of blockage.

If lung cancer is suspected, a sputum specimen should be collected. If the sputum specimen is negative, a biopsy may be taken. The results of the biopsy will help the doctor decide on the best treatment.

Treatment

Treatment of superior vena cava syndrome depends on the cause of the obstruction, 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 in this summary will focus on 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 presents no problem. The following treatments can be used for superior vena cava syndrome.

Watchful waiting

A patient with good blood flow through other veins, and few symptoms may not need treatment, but 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 forego more therapy. Short-term relief for a patient who has symptoms, but who does not want aggressive treatment, may include raising the head, using corticosteroids (drugs that decrease swelling), and increasing elimination of fluids using drugs such as diuretics. Diuretics may help symptoms of swelling, but can cause problems such as dehydration.

Radiation therapy

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

Chemotherapy is the treatment of choice for sensitive tumors such as lymphoma or small cell lung cancer. The presence of superior vena cava syndrome should not change the treatment approach.

Thrombolysis (breaking up blood clots)

Superior vena cava syndrome may come about when a thrombus (blood clot) forms in a partially blocked vein. Patients who have blood clots may need treatment to dissolve or remove the blood clot.

Stent placement

A stent may be used to open up the blocked vein. A stent is a tube-like device that is inserted into the blocked area of a vein to allow blood to pass through. Sometimes, patients may also receive an anticoagulant to prevent more blood clots from forming.

Surgery

Surgical bypass of a blocked superior vena cava is used more often for patients without cancer, although it is used sometimes for cancer patients with blockages caused by cancer.

Social considerations

Patients and family members are often frightened and anxious because of the symptoms of superior vena cava syndrome, particularly 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 patients who develop superior vena cava syndrome have lung cancer, the type of treatment and care prescribed should take into account the patient's prognosis and other symptoms caused by the cancer.

Superior vena cava syndrome occurring in children

Superior vena cava syndrome 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 frequently occur in children with superior vena cava syndrome, the two 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. Therefore, superior vena cava syndrome is different from the syndrome in adults and is a serious medical emergency.

The most common symptoms in children are similar to those in adults and include coughing, hoarseness, difficulty breathing, and chest pain. Other less common but more serious symptoms include anxiety, confusion, tiredness, headache, vision problems, a sense of fullness in the ears, and fainting.

Superior vena cava syndrome is rare in children. The cause, diagnosis, and treatment of superior vena cava syndrome in children is not the same as it is in adults. While the most common cause of superior vena cava syndrome in adults is lung cancer, in children it is non-Hodgkin's lymphoma. As with adults, a possible noncancerous cause is a blood clot associated with an intravenous catheter.

The diagnosis in children is typically made with a physical exam, medical history, and chest X-ray. If lymphoma or another cancer is suspected, a biopsy is helpful for the diagnosis, but may be too dangerous for the child. Children with superior vena cava syndrome do not tolerate general anesthesia well because of its effect on the heart and lungs.

When cancer is the cause of superior vena cava syndrome, the situation may be a medical emergency, with no time to diagnose the cancer with tissue. In most cases, the best approach is to start treatment before a definite diagnosis is made. Radiation therapy is usually used to treat the tumor. After radiation therapy, breathing may become more difficult because of the rapid swelling that narrows the windpipe. In these situations, it may be necessary to give a drug that reduces swelling.

Along with radiation, chemotherapy and steroids may be used. If the tumor does not respond, it may not be cancerous. If necessary, surgery may be performed. Surgery may include a bypass to go around the blocked part of the vein. A stent may also be placed to open the vein.