Superior vena cava thrombosis is a potentially life-threatening clinical entity that mainly arises from the use of central venous catheters that may promote thrombosis and obstruction of this major vessel. Swelling of the head and neck, flushing, cyanosis, respiratory distress, and neurological deficits comprise the clinical presentation. The initial diagnosis can be made on clinical grounds, but imaging studies such as multidetector computed tomography (MDCT), magnetic resonance imaging (MRI), and sometimes standard contrast venography, are used to confirm superior vena cava thrombosis.
Superior vena cava thrombosis has a potential to result in superior vena cava syndrome (SVCS). SVCS is a well-known disorder that stems from the obstruction of the superior vena cava. By far, the most common cause of SVCS are malignancies - carcinomas of the lungs, lymphoma, mediastinal tumors, or metastatic deposits      . Thrombotic events in the superior vena cava constitute the significant proportion of the remaining SVCS cases  . The presence of indwelling intravascular devices is the main predisposing factor to superior vena cava thrombosis  . In fact, virtually any condition that causes mechanical obstruction of blood flow through this vessel can have prothrombotic effects . The clinical presentation of superior vena cava thrombosis focuses on the head and neck area, with main complaints being a sense of head fullness accompanied by flushing and swelling of the face and neck   . Respiratory manifestations such as dyspnea and stridor are not uncommon, particularly when thrombosis develops suddenly  . Other findings include prominent dilation of veins on the neck, the trunk, and the upper extremities, cyanosis, and neurological deficits . Embolization is a rare but important and possibly life-threatening complication that may occur in superior vena cava thrombosis  .
A thorough clinical and imaging assessment is necessary to make the diagnosis of superior vena cava thrombosis. A properly obtained patient history can point to an existing condition that could predispose to the symptoms observed during the physical examination. Furthermore, a localized head and neck symptomatology with distended venous vessels are highly suggestive of an ongoing process in the superior vena cava, especially in the presence of a central venous catheter. When clinical suspicion is raised, imaging studies should be employed as soon as possible. Until recently, conventional venography was the gold standard for the evaluation of superior vena cava pathology   . The necessity for non-invasive and more sophisticated methods has resulted in the replacement of conventional venography with computed tomography (CT) and magnetic resonance imaging (MRI)  . In fact, multidetector CT (MDCT) is able to delineate the exact changes occurring in this vessel and is sufficient to make the diagnosis of superior vena cava thrombosis. Moreover, it also obtains crucial information for choosing the optimal therapeutic approach . In addition, CT and MRI angiography are described as potentially useful studies .