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. Symptoms occur when something blocks the blood flowing back to the heart.

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 lymphoma, cancer of the lung that spreads, breast cancer, testicular cancer, thyroid cancer, and thymic tumors.

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

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

Symptoms

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

Note: Symptoms may begin suddenly or gradually, and may worsen when bending over or lying down.

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