Acute thrombosis of the deep leg and pelvic veins in agenesis of the renalinferior vena cava

A 19-year-old,otherwise asymptomatic man presented to the hospital of ortho paedic surgery with acute severe pain like lumbago. Symptomatic treatment w as performed after extensive orthopaedic diagnostic procedures. On the thir d day after admission he showed clinical signs of deep vein thrombosis with painful swelling and livid discoloration of both legs. Colour duplex ultra sound revealed complete thrombosis of the leg and pelvic veins bilaterally, but the cranial extent was not clear. Contrast-enhanced helical computer t omography of the abdomen and the pelvis confirmed deep pelvic vein thrombos is and showed extention into the inferior vena cava. Moreover, the study re vealed the agenesis of the renal segment of the inferior vena cava with col lateral flow through dilated lumbar veins to enlarged azygous and hemiazygo us, through vertebral and paravertebral venous plexus. The renals were drai ned via dilated capsular veins. The agenesis of renal vena cava is a very rare anomaly causing acute thromb osis of the deep leg and pelvic veins. Other risk factors of thromboembolic disease were not found. The patient was treated successfully with systemic thrombolysis. Therefore we used ultra-high streptokinase infusion (9 million units over 6 hours). C olour duplex ultrasound revealed good flow into deep leg and pelvic veins a fter three cycle of lysis. Magnetic resonance angiography of the abdomen and pelvis was performed to e valuate the successful fibrinolysis with complete recanalisation of the pel vic veins and to demonstrate the venous anatomy. Permanent oral anticoagulation with phenprocoumon is indicated to decrease the high rate of recurrent thrombosis. Compression stockings were prescribe d. To prevent thrombosis, additional risk factors like smoking, immobilizat ion and unusual physical activity should be strictly avoided.