Posterior nutcracker syndrome with left renal vein duplication: An uncommon cause of hematuria.

INTRODUCTION: Posterior Nutcracker syndrome (NCS) is a rare anomaly in which the left renal vein passes behind the aorta which compresses it against the vertebral column, restricting the venous drainage of the left kidney.

PRESENTATION OF CASE: A 46 year-old lady presented with intermittent painless hematuria for 6 years. Urinalysis showed microscopic hematuria. An abdominal CT scan showed left renal vein duplication with the retroaortic branch trapped between the vertebral column and the aorta at the level of the aortic bifurcation, suggestive of posterior NCS. There were multiple small cortical cysts, sand-like stones in the left kidney and duplication of both right and left renal arteries.

DISCUSSION: Posterior NCS in a patient with a duplicated left renal vein may not show all the clinical features of a typical NCS as the elevated pressure due to compression is dissipated through the pre-aortic branch of the duplicated renal vein. CT Angiography can be helpful in such a patient with multiple abnormalities. Management can range from simple surveillance to nephrectomy depending on the symptoms and renocaval pressure gradient.

CONCLUSION: Although posterior NCS is a rare anomaly of the left renal vein, it should be considered in the differential diagnosis of haematuria.