A condition in which there is compression of the left renal vein between the aorta and superior mesenteric artery, leading to elevated left renal vein pressure and possible development of collateral veins.

Patients typically present with intermittent hematuria without associated abdominal pain or flank pain. Other common presenting symptoms include proteinuria, gonadal vein syndrome, and varicocele due to development of collateral vessels.

For many patients, nutcracker syndrome is incidentally discovered on imaging done for another cause.