[Nutcracker syndrome: a cause of unexplained hematuria].

Hematuria is frequently encountered in clinical practice. Its diagnostic spectrum is wide: urinary tract infection, lithiasis, malignant tumor and nephropathy. In the absence of one of these causes, the nutcracker syndrome must be evoked. It results from compression of the left renal vein between the abdominal aorta and the superior mesenteric artery. Knowing how to diagnose it can avoid morbid consequences (chronic renal disease, renal vein thrombosis). In addition to hematuria, its main symptoms are left lumbago, varicoceles, and orthostatic proteinuria. The clinical picture and complementary examinations (ultrasound-doppler, computed tomography angiography, magnetic resonance angiography, and phlebography) generally allow the diagnosis to be made. Treatment varies according to age and severity of symptoms.