Should this case really be in the exam?  It's a bit of an emergency isn't it? 

Approach

1. Inspection
   • Tortuous dilated veins overlying chest wall and neck
   • Face may be plethoric and swollen
   • Comment if patient is dyspnoeic at rest

Completion

1. Examine further to find cause for obstruction
2. Stigmata of lung carcinoma -nicotine stains, clubbing, horner's syndrome, lymphadenopathy
3. Examine chest

Causes of SVC obstruction

1. Within SVC
   • Thrombosis (eg from CVP lines) - [treated by thrombolysis, angioplasty and stenting]
2. Outside SVC
   • Carcinoma of lung
   • Lymphoma
   • Carcinoma of thyroid
   • Aortic aneurysm
   • Mediastinal goitre
   • Mediastinal fibrosis
   • Constrictive pericarditis

Determining extent of obstruction

1. IV injection of contrast into the veins in the arm can illustrate degree of obstruction
2. CT thorax: may demonstrate cause of obstruction

Inferior venae cava obstruction

• Dilated veins observed across trunk
• Commonest cause = intra-abdominal malignancy

Caput Meduase

• Dilated veins around a porto-systemic anastmosis in the umbilical veins 

Dilated abdominal veins can be distinguished  with Harvey's test: - determines direction of flow

SVC obstruction: direction of flow above umbilicus downwards

IVC obstruction: direction of flow below umbilicus upwards

Caput medusae: direction of flow away from umbilicus