Definition and Overview
Superior vena cava syndrome (SVCS) is a common symptom of benign and malignant conditions that affect the upper chest.
Superior vena cava is one of the largest veins in the body and is responsible for carrying deoxygenated blood from the head and arms to the right atrium of the heart. SVCS occurs when the superior vena cava is compressed by surrounding structures usually due to benign abnormal growths or malignant tumours. It can also occur if a blood clot gets stuck in the vein and disrupts normal blood flow.
Superior vena cava obstruction syndrome is rarely a medical emergency. In many cases, it develops very slowly, which gives other veins in the upper chest enough time to enlarge in order to accommodate extra blood flow. When this happens, superior vena cava syndrome symptoms are either mild or non-existent. If SVCS develops very quickly and if the airway is completely blocked, a ventilator is used to help with breathing until the blockage is removed.
SVCS can affect any person of any age including children. Because children have significantly narrower airways than adults, the condition is considered a life-threatening emergency in paediatric oncology. Children with clinical evidence of SVCS are usually admitted to the intensive care unit (ICU) where their vital signs are closely monitored.
Causes of Condition
Superior vena cava is a thin-walled vessel. Thus, it is easily compressed when there is a tumour in the chest or when lymph nodes become enlarged when cancer spreads to the lungs.
The most common causes of superior vena cava syndrome are lung cancer and non-Hodgkin lymphoma (NHL). Although rarely, it can also occur as a sign or symptom of the following:
Certain types of infection including tuberculosis and syphilis
Metastatic breast cancer
Metastatic germ cell tumours
Other tumours in the mediastinum
Other than malignant and benign growths, vena cava superior syndrome can also be caused by blood clots that get stuck inside the vein and block normal blood flow. Blood clot formation can be a result of certain medical procedures including the implantation of a pacemaker and other types of catheter-based procedures performed in the upper chest.
Signs and symptoms of superior vena cava syndrome are barely noticeable if the vein is only partially blocked or when other veins are accommodating the extra blood flow. However, symptoms become obvious as the condition progresses. These include:
Respiratory symptoms including shortness of breath and dry cough. Sometimes, patients also present with hoarseness and chest pain.
Central nervous symptoms, such as visual changes, headaches, seizures, and impaired consciousness
Venous obstructions resulting in the swelling of the arms and face
These symptoms are more severe in children than adults.
Rare symptoms of superior vena cava syndrome include coughing up blood from the lungs and throat, swelling of the veins in the neck and chest, difficulty swallowing, bluish skin due to the lack of oxygen, vocal cord paralysis, and Horner’s syndrome.
Who to See and Types of Treatments Available
Superior vena cava syndrome is often experienced by patients with some types of cancer. Thus, checking for SVCS is usually a part of their cancer treatment and management especially if symptoms mentioned above are present.
Superior vena cava syndrome is diagnosed with a chest x-ray, which can reveal any abnormal growth in the chest area. Other tests that can be carried out to gather more information and to rule out other medical conditions include:
Magnetic resonance imaging (MRI) - Creates pictures of organs and structures inside the body using pulses of radio wave energy and magnetic field. It can provide additional information that cannot be obtained from other imaging tests including x-rays.
Computed tomography (CT) scan - Provides more detailed images of internal organs, soft tissue, and blood vessels than an x-ray.
Ultrasound - Captures live images from the inside of the body using high-frequency sound waves.
Venography - A type of an x-ray test that uses contrast material injected into the body to check the blood flow through veins. It is useful in finding the exact location of blood clots.
In some patients, watchful waiting is advised if there are no symptoms or if the symptoms are very mild.
If treatment of superior vena cava syndrome is required, it will focus on relieving the symptoms. Patients are prescribed with diuretics (to remove excess fluid from the body) and corticosteroids (to reduce swelling). If the condition is caused by a blood clot, treatment options include:
Thrombolysis - A procedure that dissolves clots in blood vessels to improve blood flow. It can be performed by delivering drugs through an IV line or with the use of a long catheter specifically designed to either break up or remove the clot.
Stenting - Involves inserting an expandable metal stent into the superior vena cava to keep it open. This procedure is known to provide rapid clinical improvement.
Bypass surgery - Doctors can perform a procedure that bypasses the blockage to restore normal blood flow. This is recommended to a highly selected group of patients whose superior vena cava compression syndrome is caused by non-malignant diseases such as sarcoidosis and tuberculosis.
The definitive cure for superior vena cava obstruction syndrome is the treatment of the underlying condition. Often, this means removing abnormal growths and enlarged lymph nodes with surgery, chemotherapy, or radiotherapy.
Chemotherapy is usually the treatment of choice for lymphoma and small cell lung cancer. Chemotherapy drugs work by killing cancer cells or preventing them from growing. If the tumour is not responding well to chemotherapy, radiation therapy, which uses high-energy x-rays to kill cancer cells, is recommended.
The prognosis for patients with super vena cava syndrome can be affected by many factors. However, it is highly dependent on the effectiveness of methods used to treat underlying conditions. In patients with advanced stages of cancer, treatment for superior vena cava syndrome is part of their palliative care, which focuses on relieving symptoms of their condition so they can be comfortable as much as possible.
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