Diseases

• A plain chest x-ray may show abnormal enlargement of the mediastinum or may reveal a tumor in the lung.
• Ultrasound may be used to look for blood clots in the arm leading into the chest.
• Computerized tomography (CT) scanning of the chest is most often used to diagnose superior vena cava syndrome. While it will show the blockage and may show a tumor, it will not necessarily diagnose the type of tumor.
• If a tumor is the cause of the obstruction, often a surgical procedure will be required to obtain a biopsy (a small piece of tissue), to help make the specific diagnosis as to the type of tumor.

Rarely does superior vena cava syndrome constitute a medical emergency. The ABCs of care are always a priority, insuring that the Airway is well maintained, Breathing is adequate and the Circulation (blood pressure and heart rate) is stable. The patient may feel more comfortable in an upright position. Furosemide (Lasix) is a diuretic that will decrease the volume of fluid within the bloodstream. With less pressure pushing against the obstructed superior vena cava, symptoms may be temporarily relieved. Treatment needs to be directed to the underlying cause. If the cause is a tumor or cancer, the treatment plan will need to be customized to the patient's condition and desires. Options include radiation with or without chemotherapy. Even with aggressive treatment with radiation, only 10 % of lung cancer patients with this syndrome survived to 30 months. Without any treatment, survival may be less than a month. Steroids [for example, methylprednisolone (Medrol, Depo-Medrol) or prednisone (Deltasone, Liquid Pred)], may be considered to decrease the swelling of a tumor pressing on the superior vena cava and help relieve symptoms. If the cause of superior vena cava syndrome is a blood clot, anticoagulation with (warfarin) Coumadin may be indicated. The use of thrombolytic drugs [for example, alteplase (Activase, TPA) or TNK] to break up the clot, or placement of a stent to keep the vein open may also be considered. Special consideration In children, superior vena cava syndrome is most often caused bynon-Hodgkin's lymphoma. The compression of the superior vena cava may be associated with compression of the trachea as well. The trachea (windpipe) in children is relatively narrow, flexible, and soft as compared with an adult. Airway obstruction may occur and manifest as:

• difficulty breathing,
• stridor (high-pitched, abnormal breathing sounds heard when breathing in), and
• wheezing.

Initially, there are few symptoms, however, over time, symptoms of superior vena cava gradually develop. As the compression becomes more severe, the patient may develop shortness of breath and swelling of the arms and face. The symptoms occur because blood cannot return to the heart. Without adequate blood return, it is hard for the heart to pump newly oxygenated blood to meet the metabolic needs of the body. If blood cannot return to the heart, it starts to back up and causes swelling of the areas where the backup occurs. Less common symptoms include:

• dilation of veins on the skin surface as the body tries to establish new circulatory pathways to bypass the blockage, and a blue tinge to the skin (because the backed up blood doesn't have enough oxygen content)
• cough,
• shortness of breath,
• chest pain, and
• hoarseness.

The most common cause of superior vena cava syndrome is cancer. Primary or metastatic cancer in the upper lobe of the right lung can compress the superior vena cava. Lymphoma or other tumors located in the mediastinum can also cause compression of the superior vena cava. Less often, the superior vena cava can become blocked with a blood clot from within. As more invasive medical procedures are being performed on patients, this cause of superior vena cava syndrome is being seen more frequently. Blood clot (thrombus) formation that causes superior vena cava syndrome is a complication of pacemaker wires,dialysis, and other intravenous catheters that are threaded into the superior vena cava. Historically, and in other parts of the world, infection (syphilis and tuberculosis) is another cause of superior vena cava syndrome. Sarcoidosis (a disease that results in masses of inflamed tissue) may also cause this syndrome.

The superior vena cava is a large vein located in the upper chest, which collects blood from the head and arms and delivers it back to the right atrium of the heart. If this vein is compressed by outside structures, or if a thrombus or clot develops within it, return blood flow to the heart is impeded. When blood flow to the heart is restricted, the increased pressure in the veins of the face and arms causes edema (fluid buildup) in these areas. This condition is referred to as superior vena cava syndrome.Because the superior vena cava, like all veins, has a thin wall (there are no muscles in the walls of a vein as compared to the walls of an artery), and because there is little pressure inside the vein, it can be easily compressed by outside structures. The superior vena cava lies next to the upper lobe of the right lung and within the mediastinum [the space that contains the central structures of the chest: the heart, the trachea, the esophagus and the great vessels (aorta, vena cava)]. Abnormalities within any of these structures can cause the compression.

The outcome and prognosis is dependent upon the underlying cause of the superior vena cava syndrome.