[48-year-old female patient with Crohn's disease and new hematuria and proteinuria].

We report on a 48-year-old patient with Crohn's disease and left abdominal pain, who presented with hematuria and proteinuria. As reason we found a left renal vein thrombosis. This diagnosis was based on magnetic resonance imaging and doppler ultrasound. The incidence of thrombembolic complications in patients with chronic inflammatory bowel disease is increased, however renal vein thrombosis is a very rare complication of Crohn's disease. We started a conservative treatment with phenprocoumon. Thereafter the patient remained asymptomatic and the thrombus dissipated during follow-up.