Nutcracker syndrome: an underdiagnosed cause for hematuria?

Since its description in 1972, the Nutcracker Syndrome or Aorto-Mesenteric Left Renal Vein Entrapment Syndrome has been mentioned in the literature as an infrequent cause of hematuria originating from the left collecting system. It describes compression of the left renal vein in the fork between the abdominal aorta and the proximal Superior Mesenteric Artery (SMA), close to its origin. This results in left renal venous hypertension leading to the development of collateral veins with intrarenal and perirenal varicosities which can cause hematuria if the thin-walled septum separating the veins from the collecting system ruptures. The main presenting symptom is hematuria, with or without left flank pain. Some patients may present with left flank pain alone and, in a few, varicocele might be the only complaint. Exercise seems to aggravate the symptoms. It still remains unclear why compression of the left renal vein occurs in only a few patients despite its very peculiar course between the aorta and the SMA. Different anatomical details have been proposed. This controversy reflected itself on the lack of a clear agreement in regard to the treatment. We did a general overview of the current literature in an effort to elucidate further its pathophysiology. We present here three cases. The first case is that of a lady who presented with intermittent hematuria, sixteen years apart. Her hematuria cleared spontaneously without surgical intervention. Given her long symptom free interval, we strongly suspect some variable constitutional factors to play a role in the symptom development. The second case represents a perfectly healthy asymptomatic young women in whom an IVP done as routine renal donor work up revealed irregularities within the left collecting system that proved to be periureteric varices secondary to a nutcracker phenomenon as proved later by a renal angiogram. The third case describes a hypertensive, otherwise healthy, middle-aged male in whom an asymptomatic Nutcracker Phenomenon disclosed itself during a renal angiographic work up for his intractable hypertension. It is likely that the incidence of this anatomical problem is rather underestimated. We would like to emphasize the importance of its early inclusion in the differential diagnosis of left-sided hematuria because of the need for special testing for its diagnosis. Early proper diagnosis would spare many unneeded investigations.