Superior vena cava syndrome

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The superior vena cava is the large vein that carries blood from the head, neck, arms and chest to the heart. Superior vena cava syndrome (SVCS) is a group of symptoms that occur when there is pressure on the superior vena cava, or it is partially blocked and blood can’t flow back to the heart normally. This causes more pressure in the veins and face, which leads to a buildup of fluid or swelling.

SVCS most commonly occurs in people with lung cancer or lymphoma. SVCS is rare in children, but if it does happen it is a medical emergency because the swelling can block their windpipe, or trachea, so they can’t breathe. In adults, how quickly the superior vena cava becomes blocked determines how serious SVCS is.


SVCS is usually caused by cancer in the chest that is near the superior vena cava or surrounding lymph nodes. There are a few different ways that cancer can cause SVCS:

  • A tumour in the chest can press on the superior vena cava.
  • A tumour can grow into the superior vena cava and block it.
  • Cancer can spread to the lymph nodes near the superior vena cava. The lymph nodes can get larger and press on or block the vein.
  • Cancer can cause a blood clot in the vein.

SVCS can also be caused by benign, or non-cancerous, factors. Having a pacemaker or catheter can increase your chances of developing a blood clot in the superior vena cava, which could lead to SVCS. Approximately 30% of SVCS cases are caused by benign factors.


Symptoms of SVCS can vary depending on the cause and other factors. SVCS may develop slowly or suddenly, depending on how quickly the superior vena cava is affected.

Common symptoms include:

  • shortness of breath (dyspnea) or difficulty breathing
  • coughing
  • swelling of the face, neck, upper body and arms
  • changes to vision

Other symptoms include:

  • a feeling of fullness in the head or ears
  • a hoarse voice or trouble swallowing or talking
  • chest pain
  • coughing up blood
  • swollen veins in the chest or neck
  • blue lips or skin
  • a small pupil, a drooping eyelid and no sweating on one side of the face (Horner's syndrome)
  • headache
  • feeling dizzy or lightheaded

Report any symptoms to your doctor or healthcare team right away.


Your doctor will try to find the cause of SVCS. It is usually diagnosed by:

  • a physical exam
  • a chest x-ray
  • a CT scan
  • an ultrasound
  • a venogram, which is an x-ray of veins in the upper body

A physical exam and chest x-ray are usually all that are needed to diagnose SVCS in children. A biopsy may not be done even if the doctor thinks cancer is causing SVCS because the child’s heart and lungs may not be able to handle anesthesia.

Find out more about these tests and procedures.

Treating SVCS

Once SVCS is diagnosed, your healthcare team will treat it. If you have good blood flow through other veins, few symptoms or an open airway, you may not need treatment right away. If the trachea becomes blocked or you have serious problems caused by pressure on the nerves, SVCS can become life-threatening and must be treated right away.​

​​SVCS is usually managed by treating the cancer that is causing it. You may have chemotherapy, immunotherapy, radiation therapy or a combination of therapies.

You may also be given other short-term treatments to reduce your symptoms and improve blood flow. You may need to have one or more of the following treatments.


Depending on your symptoms and the severity of SVCS, you may be given one or more of the following:

  • corticosteroids to reduce swelling
  • diuretics to help your body make more urine, which removes extra fluid from the body
  • blood thinners to stop blood clots from forming
  • bronchodilators to widen the tubes (called bronchi and bronchioles), or airways, in your lungs and help you breathe easier

Oxygen therapy

Oxygen therapy is oxygen given through a mask or tubes in your nostrils to give you extra oxygen.

Stent placement

A stent is a tube-like device that is placed in the blocked area of the superior vena cava. It opens up the vein and allows blood to pass through.


Surgery to bypass (go around) the blocked part of the vein can help re-route blood, allowing it to flow better. Surgery for SVCS is usually used for people without cancer, but sometimes it is used for people with cancer.

Treating SVCS in children

SVCS in children is usually treated before the cancer causing it is diagnosed. The following treatments may be used for SVCS in children:

  • radiation therapy if a tumour is blocking the vein
  • corticosteroids to reduce swelling
  • chemotherapy
  • stent placement
  • surgery so blood can flow around the blocked part of the vein

Expert review and references

  • Donna Maziak, MD, MSc, FRCPC
  • American Society of Clinical Oncology (ASCO) . Superior Vena Cava Syndrome . 2020 :
  • National Cancer Institute . Cardiopulmonary Syndromes (PDQ®)–Patient Version . National Institutes of Health ; 2019 :
  • Azizi, A, Shafi, I, Shah, N. et al.. Superior Vena Cava Syndrome. Journal of the American College of Cardiology. Superior Vena Cava Syndrome. 2020: 13 (24) 2896–2910..
  • Cedars-Sinai. Superior Vena Cava Syndrome. Los Angeles, CA: Tuesday, December 05, 2023.
  • Gupta V, Ambati SR, Pant P, Bhatia B. . Superior vena cava syndrome in children. National Institute of Health (NIH). Superior Vena Cava Syndrome in Children. 2008: 24(1):28-30.

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