Superior vena cava syndrome
Superior vena cava syndrome (SVCS), is a group of symptoms caused by obstruction of the superior vena cava ("SVC"), a short, wide vessel carrying circulating blood into the heart. The majority of cases are caused by malignant tumors within the mediastinum, most commonly lung cancer and non-Hodgkin's lymphoma, directly compressing or invading the SVC wall. Non-malignant causes are increasing in prevalence due to expanding use of intravascular devices (such as permanent central venous catheters and leads for pacemakers and defibrillators), which can result in thrombosis.[2] Other non-malignant causes include benign mediastinal tumors, aortic aneurysm, infections, and fibrosing mediastinitis.[3]
Superior vena cava syndrome (Mediastinal syndrome)
SVC obstruction[1]
Characteristic features are edema (swelling due to excess fluid) of the face and arms and development of swollen collateral veins on the front of the chest wall. Shortness of breath and coughing are quite common symptoms; difficulty swallowing is reported in 11% of cases, headache in 6% and stridor (a high-pitched wheeze) in 4%. The symptoms are rarely life-threatening, though edema of the epiglottis can make breathing difficult, edema of the brain can cause reduced alertness, and in less than 5% of cases of SVCO, severe neurological symptoms or airway compromise are reported. Resolution of superior vena cava syndrome is directly related to the treatment of the underlying compression.[4]
Shortness of breath is the most common symptom, followed by face or arm swelling.[5]
Following are frequent symptoms:
Superior vena cava syndrome usually presents more gradually with an increase in symptoms over time as malignancies increase in size or invasiveness.[5]
Treatment[edit]
Several methods of treatment are available, mainly consisting of careful drug therapy and surgery.[5] Glucocorticoids (such as prednisone or methylprednisolone) decrease the inflammatory response to tumor invasion and edema surrounding the tumor.[5] Glucocorticoids are most helpful if the tumor is steroid-responsive, such as lymphomas. In addition, diuretics (such as furosemide) are used to reduce venous return to the heart which relieves the increased pressure.[5]
In an acute setting, endovascular stenting by an interventional radiologist may provide relief of symptoms in as little as 12–24 hours with minimal risks.
Should a patient require assistance with respiration whether it be by bag/valve/mask, bilevel positive airway pressure (BiPAP), continuous positive airway pressure (CPAP) or mechanical ventilation, extreme care should be taken. Increased airway pressure will tend to further compress an already compromised SVC and reduce venous return and in turn cardiac output and cerebral and coronary blood flow. Spontaneous respiration should be allowed during endotracheal intubation until sedation allows placement of an ET tube and reduced airway pressures should be employed when possible.
Prognosis[edit]
Symptoms are usually relieved with radiation therapy within one month of treatment.[5] However, even with treatment, 99% of patients die within two and a half years.[5] This relates to the cancerous causes of SVC found in 90% of cases. The average age of disease onset is 54 years.[5]