Superior Vena Cava Syndrome: Definition, Causes, Symptoms, Diagnosis and Treatment

It is caused by a partial blockage in the superior vena cava.

This is the vein that supplies blood to the head, neck, chest, and arms to the heart.

Superior vena cava syndrome 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 can also occur from non-cancerous causes. Superior Vena Cava Syndrome is serious when it occurs in adults and is life-threatening in children.

Superior Vena Cava

The main 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 blood from the lower body.

The superior vena cava has thin walls and the blood is under pressure. It is located near the lymph nodes in the chest. Therefore, when the heart’s lymph nodes or aorta become enlarged, the superior vena cava is squeezed, blood flow slows, and complete blockage can occur.

The speed of the blockage and its location determine the severity of the syndrome.

If the blockage occurs above, where the superior vena cava and inferior vena cava meet, the syndrome is less obvious, as the veins can swell more easily and handle the increased blood flow.

If the blockage occurs below this point, more symptoms are seen, as blood must be returned to the heart through the veins in the upper abdomen and the inferior vena cava, requiring increased pressure.

Sometimes the other veins can take over the superior vena cava if it is blocked, but this takes time.

Superior Vena Cava Syndrome is usually a sign of locally advanced lung cancer. Survival will depend on the degree of the disease.

Causes of Superior Vena Cava Syndrome

Superior Vena Cava Syndrome in most cases are attributed to cancer, with the most common causes being lung cancer and non-Hodgkin’s lymphoma.

A rare cause of Superior Vena Cava Syndrome is an infection that occurs in the mediastinum causing thickening and hardness of the mediastinal tissues.

Other rare causes of superior vena cava syndrome include:

  • Germ cell tumors.
  • Metastatic breast cancer.
  • Colon cancer.
  • Sarcoma de Kaposi.
  • Esophagus cancer.
  • Behcet’s syndrome (a disease of the immune system).
  • Thymus tumor.
  • Thyroid tumor
  • Sarcoidosis (a rare inflammatory disease that causes lumps to form in the body’s organs, most often the lungs).
  • Blood clot in the vein caused by an IV catheter or pacemaker lead.


Superior Vena Cava Syndrome can cause the following symptoms:

  • Difficulty breathing.
  • Fast breathing.
  • Tos.
  • Swelling that occurs on the face, neck, upper body, and arms.

In rare cases, people may have these signs or symptoms:

  • Ronquera.
  • Chest pain.
  • Difficulty swallowing
  • Cough with bloody sputum.
  • Cyanosis (lack of oxygen in the blood).
  • Horner syndrome (constricted pupil, drooping eyelid and no sweating on one side of the face).
  • Paralyzed vocal cords.


Once Superior Vena Cava Syndrome is diagnosed, immediate care is important.

As long as the windpipe is not blocked, Superior Vena Cava Syndrome is not usually a life-threatening emergency. Therefore, a definitive diagnosis must be made before starting treatment.

These tests can be used to find out the site and the type of blocking:

  • Chest X-ray.
  • Computed tomography.
  • Venography (imaging of the veins).
  • Magnetic resonance.
  • 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 the best treatment.


The treatment of superior vena cava syndrome will depend on the cause that produces the blockage, the severity of the symptoms and the prognosis of the patient.

Radiation therapy and chemotherapy should not be started until the cause of the blockage is determined. Treatments focus on an upper vena cava blockage caused by cancer.

Since the treatment of blockage may depend on the type of cancer, this diagnosis should be made before starting treatment.

When the airways are not blocked or the brain is not inflamed, you can wait to start treatment.

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 they must be closely monitored for new symptoms or changes.

In many cases, Superior Vena Cava Syndrome 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 meet, and other veins can replace the superior vena cava, symptoms may stabilize and the patient may feel comfortable enough not to need further therapy.

Relief without resorting to aggressive treatment may include:

  • Keep your head up.
  • Using corticosteroids (medications that decrease swelling)
  • Increase fluid elimination with medications such as diuretics. Diuretics can help with symptoms of bloating. Although they can cause problems like dehydration.

Radiation therapy

When superior vena cava blockage is caused by a tumor that cannot be controlled with chemotherapy, radiation therapy may be given.


Chemotherapy is the treatment of choice for sensitive tumors such as lymphoma or small cell lung cancer.

Thrombolysis (breakdown of blood clots)

Superior Vena Cava Syndrome can appear when a thrombus (blood clot) forms. People who have blood clots may need treatment to dissolve or remove the blood clot.

Stent placement

A stent can be used to open the blocked vein. A stent is a tube-shaped device that is placed in the blocked part of a vein to allow blood to pass through.

Anticoagulant treatments are also being done to prevent more blood clots from forming.


Surgical bypass of a blocked superior vena cava is also used for patients with blockages caused by cancer.

Social considerations

Patients and their families should receive as much information as possible about the cause, symptoms, and their short-term treatment.

When aggressive treatment is deferred due to terminal cancer, patients and their families can be taught to treat the symptoms.

Because most adults who develop Superior Vena Cava Syndrome have lung cancer, the type of treatment and care prescribed must take into account the person’s prognosis and other symptoms caused by the cancer.

Superior vena cava syndrome in children

Superior vena cava syndrome refers to blockage of the superior vena cava, while compression of the trachea (windpipe) is called superior mediastinal syndrome. Since upper mediastinal syndrome and the resulting respiratory problems often occur in children with Superior Vena Cava Syndrome, the 2 syndromes are considered the same in children.

Since in children, the windpipe is smoother and the diameter of the windpipe is smaller, it is more likely to be reduced. Therefore, any swelling of the trachea can cause severe breathing problems.

Superior Vena Cava Syndrome in children is a serious medical emergency.

The most common symptoms in children are like those in adults. They include:

  • Tos.
  • Ronquera.
  • Difficulty breathing.
  • Chest pain.
  • Anxiety.
  • Confusion.
  • Fatigue.
  • Headache.
  • Vision problems.
  • Feeling of fullness in the ears.
  • Fainting.

The cause, diagnosis and treatment of Superior Vena Cava Syndrome in children are not the same as in adults.

The most common cause of superior vena cava syndrome in children is non-Hodgkin lymphoma. As with adults, a possible non-cancerous cause is a blood clot from an IV catheter.

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 Superior Vena Cava Syndrome, the situation can be a medical emergency, with no time to diagnose cancer with tissue. In some cases, the best approach is to start treatment before making a definitive diagnosis.

Radiation therapy is generally the initial treatment to treat the tumor. Once the condition stabilizes, a biopsy may be safer. Along with radiation, chemotherapy and steroids can be used.

Surgery may be necessary which may include a bypass to divert blood flow from the blocked part of the vein, or the placement of a stent to widen the vein at the obstruction and regain blood flow through it.