<prompt> A 45-year-old man presents with exertional dyspnea and pitting pedal edema. His neck veins are dilated. A diagnosis of superior vena cava SVC syndrome is made. What will you do next?Do total blood count and peripheral smearDo a CT chestStart cyclophosphamideStart radiotherapy  <response>: ANS. BThis shows an approach to a case of SVC syndrome which clearly says that first step is CT chest with contrast. This helps us to arrive at a cause for SVC syndrome and treat accordingly.Various causes of SVC syndrome are: 