SVC obstruction Health Article

Definition

SVC obstruction is a narrowing or blockage of the superior vena cava -- the second largest vein in the human body. The superior vena cava moves blood from the upper half of the body to the heart.

Alternative Names

Superior vena cava obstruction; Superior vena cava syndrome

Causes, incidence, and risk factors

Superior vena cava (SVC) obstruction is a relatively rare condition.

Most often it is caused by cancer or a tumor in the mediastinum (the area of the chest under the breastbone and between the lungs).

The types of cancer that can lead to this condition include:

• Breast cancer
• Lymphoma
• Metastatic lung cancer (lung cancer that spreads)
• Testicular cancer
• Thyroid cancer
• Thymic tumors

Superior vena cava obstruction can also be caused by noncancerous conditions that cause scarring. These conditions include lung infections (such as tuberculosis), histoplasmosis infection, and inflammation of a vein ( thrombophlebitis).

Other causes of superior vena cava obstruction include blood clots in the superior vena cava, aortic aneurysm, constrictive pericarditis, and enlargement of the thyroid gland (goiter).

Symptoms

Symptoms occur when something blocks the blood flowing back to the heart. They may begin suddenly or gradually, and may worsen when bending over or lying down.

• Decreased alertness
• Dizziness
• Fainting
• Headache
• Vision changes
• Neck swelling, facial swelling, or arm swelling
• Reddish face or cheeks
• Reddish palms
• Reddish mucous membranes (inside the nose, mouth, and other places)
• Redness changing to blueness later
• Sensation of head or ear "fullness"
• Swelling around the eye socket

Signs and tests

An examination may show enlarged veins of the face, neck, and upper chest. Blood pressure is often high in the arms and low in the legs.

A bronchoscopy may be performed if lung cancer is suspected.

Obstruction of the SVC may show on:

• Chest x-ray
• CT scan of the chest or MRI of chest
• Coronary angiography
• Doppler ultrasound
• Radionuclide ventriculography

This disease may also alter the results of the following tests:

• Liver scan
• Abdominal MRI