Video Duration: 4 minutes
Obstruction of the superior vena cava causing interrupted venous return from the head, thorax and upper extremities into the right atrium.
65% of cases are caused by malignancy. Most common malignant causes are:
Malignant causes affect males > females. Middle-aged to elderly men are more commonly affected by malignant causes of SVC obstruction.
Benign causes: males = females. More common in younger people.
Infectious causes (e.g. syphilitic aortic aneurysm, TB) used to be very common; now very rare.
The SVC has a thin wall and can be obstructed by intraluminal, mural or extrinsic factors.
Slowly progressive SVC obstruction (i.e. several weeks - months) can allow the formation of collateral circulation to drain the venous flow. This happens via the azygous and internal mammary venous systems mainly, but also the long thoracic venous system leading to the femoral and vertebral veins.
Acute SVC obstruction is often a medical emergency.
SVC obstruction usually increases the cervical venous pressure to 20 - 40 mmHg, where the normal pressure is 2 - 8 mmHg.
Minor symptoms and signs are often overlooked, but patients may complain of the following symptoms.
Patients often also have anorexia, some weight loss and haemoptysis, though these symptoms are much less specific.
ESR & CRP - elevated in patients with infection or immunological disorders.
Consider a biopsy of the tumour to confirm the presence of malignancy in a new patient with no cancer diagnosis.
In patients with ongoing SVC obstruction (i.e. not acute) with a malignant cause: