Emergencies in oncology.

A diagnosis of superior vena cava obstruction (SVCO) is usually made from the clinical picture that arises from obstruction of the venous drainage of the upper body: oedema of the arms and face, distended neck and arm veins, headaches and a dusky skin colouration over the chest, arms and face. Collaterals may develop over a period of weeks and the direction of blood flow helps confirm the diagnosis. The most important clinical sign is loss of pulsation in the venous system of the neck. Obstruction of the SVC by mediastinal tumours occurs most frequently with lung cancers, especially small cell lung cancer. Other causes, including nonmalignant, are given in Table 2. The severity of symptoms relates to the rate of degree of obstruction and the development of compensatory collateral venous drainage. The symptoms may worsen by lying flat or bending which further stresses the obstructed venous return. The common symptoms and signs in SVCO are given in Table 3.