Nutcracker syndrome: diagnosis and therapy

Abstract

Nutcracker syndrome (NCS) is an extrinsic compression of the left renal vein (LRV) by the superior mesenteric artery (SMA) anteriorly and aorta posteriorly resulting in renal vascular congestion manifesting as hematuria, proteinuria, orthostatic hypotension, pain, or even renal dysfunction. Longstanding venous compression can encourage collateral drainage pathways through gonadal and pelvic veins, which may explain reported symptom and syndrome overlap with pelvic congestion syndrome. Diagnosis can be challenging and variable, frequently involving a combination of ultrasound Doppler, cross-sectional, and invasive imaging. Often, intravascular pressure measurements are required to prove a renocaval pressure gradient to aid in a definitive diagnosis. Conservative management is appropriate, especially in children, who tend to outgrow the disorder. In the interim, medical management with angiotensin converting enzyme inhibitors (ACEIs) is a useful therapy to manage orthostatic hypotension in the pediatric population.In adults, invasive therapies are more frequently pursued. These are aimed at relieving the extrinsic compression on the LRV. The standard of care is renal vein transposition, with renal autotransplantation reserved for recalcitrant cases. Endovascular stenting is a less invasive option. Laparoscopic placement of an exovascular stent is a newer therapy intended to minimize trauma to the LRV. In this review, we will discuss the clinical manifestations, diagnostic criterion, imaging features, and conservative and surgical therapies for this condition.

How to define and assess the clinically significant causes of hematuria in childhood

“…Compression of the left renal vein (LRV) by the superior mesenteric artery and aorta, causing renal vein congestion and resulting in hematuria, is aptly called nutcracker syndrome (NCS) [ 60 , 61 ]. The proposed mechanism in explaining hematuria is that increased venous pressure into the LRV and left gonadal vein can lead to rupture of the septa between the venules and the collecting system in the kidney parenchyma.…”

“…No glomerular damage has been reported in NCS [ 60 ]. It can also cause (orthostatic) proteinuria, left flank pain, but is regarded as a benign condition in most cases [ 29 , 61 ]. An external sign suggesting the presence of NCS is a left varicocele in boys due to the formation of collaterals.…”

Daily persistent headache with nutcracker physiology and spinal epidural venous congestion: Treatment with lumbar vein embolization

“…Surgical procedures such as renal autotransplant and/or renal vein transposition are the primary treatment options available for nutcracker syndrome [12 , 13] . Percutaneous embolization of refluxing veins has shown improvement in other venous compression syndromes, such as gonadal vein embolization for the treatment of pelvic venous congestion syndrome [6 , [14] , [15] , [16] .…”

Diagnosis and Management of Pelvic Venous Disorders in Females

“…Several therapies have been proposed for left renal vein compression, including conservative management, surgical treatment (transposition of the renal vein, renal autografts, and/or transposition of the ovarian vein at the level of the common iliac vein), and endovascular treatment (stenting), but the level of supporting evidence is low [ 33 , 34 ].…”