This may arise from occlusion by extrinsic pressure, intraluminal thrombosis, or direct invasion of the vessel wall. Most cases are due to tumour within the mediastinum, of which up to 75% will be primary bronchial carcinomas. About 3% of patients with carcinoma of the bronchus and 8% of those with lymphoma will develop obstruction.
Other cancers 3-13%
Benign causes (now rare) Benign goiter, aortic aneurysm
(syphilis), thrombotic syndromes, idiopathic sclerosing mediastinitis Unknown or undiagnosed 5%
Conventionally, obstruction of the superior vena cava has been regarded as an oncological emergency requiring immediate treatment. If it is the first presentation of malignancy, treatment will be tempered by the need to obtain an accurate histological diagnosis to tailor treatment for potentially curable diseases, such as lymphomas or germ cell tumours, and for diseases such as small cell lung cancer that are better treated with chemotherapy at presentation.
In advanced disease, patients need relief from acute symptoms—of which dyspnoea and a sensation of drowning can be most frightening—and high dose corticosteroids and radiotherapy or chemotherapy should be considered. In non-small cell lung cancer palliative radiotherapy gives symptomatic improvement in 60% of patients, with a median duration of palliation of three months. Up to 17% of patients may survive for a year. If radiotherapy is contraindicated or being awaited, corticosteroids alone (dexamethasone 16 mg/day) may give relief. Stenting (with or without thrombolysis) of the superior vena cava should be considered for both small cell and non-small cell lung cancer either as initial treatment or for relapse.
Urgent initiation of pharmacological, practical, and psychological management of dyspnoea is paramount and usually includes opioids, with or without benzodiazepines. Opioid doses are usually small—such as 5 mg oral morphine every four hours. It is important to review all prescriptions of corticosteroids in view of their potential adverse effects. We recommend stopping corticosteroids after five days if no benefit is obtained and a gradual reduction in dose for those who have responded.
Clinical features of superior vena caval obstruction Symptoms
• Tracheal oedema and shortness of breath
• Cerebral oedema with headache worse on stooping
• Visual changes
• Dizziness and syncope
• Swelling of face, particularly periorbital oedema
• Neck swelling
• Oedema of arms and hands
• Rapid breathing
• Periorbital oedema
• Suffused injected conjunctivae
• Non-pulsatile distension of neck veins
• Dilated collateral superficial veins of upper chest
• Oedema of hands and arms
Aetiology of obstruction of superior vena cava
Carcinoma of the bronchus 65-80%
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