[Nutcracker syndrome: a difficult case of recurrent gross hematuria]

The Nutcracker Syndrome (NS) is an uncommon clinical condition caused by compression and entrapment of the renal vein (LRV) as it passes through the angle between the superior mesenteric artery (SMA) and the aorta (meso-aortic angle). Intermittent macrohematuria, left peripelvic and gonadal vein varices and aspecific abdominal pain may be common manifestations of this syndrome.

A 15-year-old white boy developed recurrent macrohaematuria in June 2002. He had a history of upper respiratory infection prior the first episode of gross hematuria followed by 4 other episodes of macrohematuria 'sine causa'. Blood pressure and renal function were normal. Routine laboratory tests showed only an increase in serum LDH levels (901 IU/L) with negative Coombs' test, both direct and indirect, and absence of schistocytes in the blood smear. Renal ultrasonography showed normal kidneys while an intravenous pyelography showed a 'minus' in the right ureter. For this reason, a cystoscopy and a retrograde pielography were performed but resulted normal. A renal biopsy was carried out because of the presence of one episode of post-infective macrohaematuria, but light microscopy and immunofluorescence examinations were found to be normal. Renal ultrasonography and Color Doppler ultrasonography (CD-USG) oriented our diagnosis towards NS. An abdominal computerised tomography (CT) scan confirmed that the LRV was compressed between the aorta and the SMA.

NS cannot be diagnosed with routine diagnostic methods. Endoscopic and radiological methods may provide some clues for the presence of NS, while CD-USG may be considered to be the first level non-invasive method for diagnosis. The sensitivity and specificity of this test for diagnosing NS is reported as being 78% and 94%, respectively. The best treatment available for this syndrome is still being debated.