Approach
The diagnosis of superior vena cava (SVC) syndrome is usually clinical and requires a high degree of suspicion; thus, a good history and physical examination are important. Chest CT/MRI is the initial test of choice required to confirm the diagnosis and to evaluate for underlying aetiology. Obtaining tissue for histopathology may be required in cases of suspected malignancy or infection.
History
History may also be notable for smoking, multiple pacemaker leads, or central venous catheters. Previous history of radiation exposure should be noted, as excess radiation to the mediastinum can lead to fibrosis causing SVC obstruction.
Early in the course, partial SVC obstruction may be asymptomatic or associated with subtle symptoms. With progressive obstruction, the classic symptoms and signs become more obvious. The most common symptoms are facial swelling, dyspnoea, cough, arm swelling, and facial plethora.[1][2] Sudden-onset dyspnoea due to laryngeal oedema can be fatal as a result of upper airway compromise.[5] Other symptoms include headache, chest pain, blurred vision, hoarseness of voice, and stridor. Symptoms are usually worsened by bending forwards or lying down.
History of associated anorexia, weight loss, cough, dyspnoea, and haemoptysis may suggest lung malignancy (or possibly chronic infection). Fever, skin rash, or arthralgias may be indicative of underlying collagen-vascular diseases.
Physical examination
Examination usually reveals engorged veins of the neck and upper chest wall, facial oedema, and upper-extremity oedema. Prominent collateral veins covering the anterior chest wall may be visible. The manoeuvre of bending forwards usually worsens venous engorgement and is a helpful clinical sign. Laryngeal oedema, cyanosis, papilloedema, mental changes, stupor, and even coma have been described with severe obstruction.[1][6] When lymphadenopathy is present outside the chest, lymphoma should be considered a possibility.
Investigations
Chest x-ray may be performed as an initial test and sometimes reveals a widened mediastinum or mass lesion in the lung, but the most important radiological investigation when diagnosis is clinically suspected is chest CT (with intravenous contrast).[1][2] It establishes the diagnosis of SVC obstruction and shows the exact location, severity, and associated pathology (e.g., malignancy or intravascular thrombosis). MRI may also be useful but does not have any distinct advantages over CT, except in patients with contrast allergy or renal failure, as it avoids iodinated contrast.[1][2]
Ultrasound of the upper extremities is a useful non-invasive screening test and helps in identification of venous thrombosis or obstruction.[2][19] Presence of monophasic flow in the SVC or loss of respiratory variation on Doppler ultrasound can suggest SVC obstruction.
Bilateral upper-extremity venography can accurately delineate the site and extent of SVC obstruction and collateral pathways, but does not provide information about lung and mediastinal pathology. Venography is usually not required for diagnosis, but may be helpful to plan stent placement or surgery.[1][2]
Other investigations
Obtaining a tissue diagnosis is important to confirm the presence of malignancy. A biopsy from supraclavicular or other cervical lymph nodes may obviate the need for invasive procedures like mediastinoscopy, and thus careful examination for cervical lymphadenopathy should be performed. For diagnosis of malignancy, bronchoscopy has a diagnostic yield of 50% to 70%, transthoracic needle-aspiration biopsy has a yield of approximately 75%, and mediastinoscopy or mediastinotomy has a diagnostic yield of >90%.[1]
Sputum examination for culture, acid-fast staining, and cytology is helpful in diagnosis of cases with tuberculosis, fungal infections (e.g., aspergillosis, blastomycosis, histoplasmosis, nocardiosis), or endobronchial malignancy. Thoracentesis with cytological analysis should be strongly considered whenever pleural effusion is present.
Erythrocyte sedimentation rate or C-reactive protein may be elevated in patients with infection or immunological disorders.
Use of this content is subject to our disclaimer