Superior Vena Cava (SVC) Syndrome Overview

Symptoms, Causes, and Treatment

Superior vena cava (SVC) syndrome is a set of effects that occur when blood flow through the superior vena cava (the large blood vessel that returns blood from the upper body back to the heart) is partially or fully blocked. The symptoms include swelling of the face, arms, neck, and chest, distention of veins in the neck, and sometimes shortness of breath and a cough. SVC syndrome is usually diagnosed with a chest computerized tomography (CT) scan, but additional tests may be done as well. Treatment focuses on the underlying cause and may include a procedure to bypass the blood vessel obstruction.

doctors operating on patient
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SVC syndrome is a complication that occurs in 2 to 4% of people living with lung cancer, and in some cases, it is the first sign that leads to the diagnosis. It is most common with tumors that grow near the top of the lungs, and because of the location of these tumors, they can easily be missed on a chest X-ray.

Symptoms

The symptoms of SVC syndrome are caused by the buildup of pressure in the superior vena cava above the blockage. The superior vena cava drains blood from the head and neck, arms, and upper chest, and blockage may result in the backup of blood in veins in these regions. Possible signs and symptoms may include:

  • Swelling of the face, arms, or chest wall
  • Difficulty breathing (dyspnea)
  • Widening (distention) of the veins in the neck and chest
  • Redness of the face, neck, and palms of the hands
  • Cough and/or coughing up blood (hemoptysis)
  • Headache
  • Chest pain
  • Hoarseness
  • Difficulty swallowing (dysphagia)
  • Bluish tinge to the skin of the face or upper body (cyanosis)
  • Horner's syndrome (a constricted pupil, saggy eyelid, and lack of sweating on one side of the face)

When It's an Emergency

Superior vena cava syndrome may occur gradually, but it can be a cancer-related medical emergency in some situations.

Sometimes other nearby blood vessels can compensate for the accumulation of blood, especially if the SVC is only partially blocked—and this compensation can slow down the emergence of symptoms.

If the obstruction of the superior vena cava occurs rapidly, there may not be time for other blood vessels (called collateral blood vessels or circulation) to accommodate the increased blood flow.

Most worrisome is lung-cancer-induced SVC syndrome which can cause obstruction of the trachea (the airway that leads from the mouth and nose to the large bronchi in the lungs).

If you are experiencing any of the symptoms noted above, it's important to see your doctor right away.

Causes

The superior vena cava is a soft-walled vein and can be compressed by tumors, infections, or growths that develop nearby.

The most common cause of SVC syndrome is compression of the superior vena cava (SVC) by a cancerous tumor. Lung cancers, especially those growing in the right upper lung, are the most common cause of compression, followed by lymphomas.

The spread of other tumors, such as breast cancer to lymph nodes in the mediastinum (the area of the chest between the lungs) can also occur. Cancers such as testicular cancer, thymus cancer, and thyroid cancer may also lead to the syndrome.

Less common causes include blood clots within the SVC (often secondary to central intravenous lines or pacemaker wires), aortic aneurysms, or infections like tuberculosis or histoplasmosis.

Diagnosis

Your physical examination may show obvious swelling if you have SVC syndrome.

Radiological studies such as a chest X-ray or CT scan may show a tumor or signs suggestive of SVC syndrome. Other tests, such as magnetic resonance imaging (MRI), ultrasound, or venography (a test done using a dye to X-ray veins) may be recommended as well. If your doctor suspects that cancer could be causing your symptoms, further tests to search for cancer would be needed.

Treatments

To rapidly improve symptoms pending definitive treatment, management often includes keeping the head elevated, using corticosteroids to reduce inflammation, and taking diuretics ("water pills") to reduce swelling.

The long term treatment of SVC syndrome depends in large part upon the cause. If symptoms are due to a tumor pushing on the superior vena cava, methods to treat the tumor such as chemotherapy, targeted therapies, surgery, immunotherapy, or radiation therapy are often used. With lymphomas, treatments such as monoclonal antibodies may be used. With SVC syndrome due to metastases, treatment usually involves treating the primary cancer.

Depending on the severity of your symptoms, a stent may be surgically placed in the SVC placed to hold it open. Blood thinners may be used to prevent clotting.

In rare cases, surgery to bypass the obstruction may be needed.

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Article Sources
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