Anterior Nutcracker syndrome as a rare cause of hematuria in an 8 year old boy: A case report

Nutcracker syndrome is caused by a compression of the left renal vein between the aorta and the superior mesenteric artery. It results in left renal venous hypertension, and the subsequent development of venous varicosities of the renal pelvis, ureter, and gonadal vein. We report a rare case in an 8-year-old boy who presented with a history of intermittent episodes of hematuria leading to anemia and left flank pain. Ultrasound examination of abdomen revealed bulky left kidney and features of subacute medical renal disease. Computed tomography of abdomen showed compressed left renal vein between aorta and superior mesenteric artery. Authors report the successful operative management of this rare syndrome in a pediatric patient.


Introduction
Nutcracker syndrome (NCS) is quite rare condition and characterized by the compression of the left renal vein (LRV) between aorta and superior mesenteric artery (SMA) [1].It is also called renal vein entrapment syndrome [2].Clinical symptoms are usually caused by venous hypertension within the left kidney: leftflank pain that can radiate to the buttock and non-glomerular hematuria [3].El Sadr reported the first case in 1950 [4], but De Schepper named it [5].In normal anatomical development, the left renal vein (LRV) passes anteriorly across the abdominal aorta.
But, in rare cases, the left renal vein becomes located in a retro-aortic position,   during growth [10,11].Different approaches can be used.
Medication can be proposed only in patients suffering from isolated pelvic congestion syndrome caused by nutcracker syndrome.
In this case, symptoms can be improved by treatments effective in treating pelvic congestion syndrome, as medroxyprogesterone acetate, [12] goserelin acetate, [13] and micronized purified flavonoid fraction [14].
Hohenfellner even reported one case which was radically treated by nephrectomy [19].
More recently, endovascular treatment options have been applied [3,7,9].This approach is less invasive as it can be performed percutaneously.Endovascular treatment options include embolization, balloon angioplasty and stenting [3].
LRV transposition is nowadays regarded as the surgical method of choice, [20] /www.pediatricurologycasereports.comcompressed between the aorta and the vertebral column.The condition that LRV is anterior to the abdominal aorta is called anterior nutcracker syndrome.The other is called posterior nutcracker syndrome [6].Doppler ultrasound measurements of the anterior-posterior (A-P) diameter and peak velocities of the LRV may be helpful in diagnosis of NCS [7].Computed tomography (CT) and CT angiography, Magnetic resonance imaging (MRI) and MR angiography are other noninvasive modalities that can demonstrate compression of the LRV in the aorto-mesenteric angle and collateral veins [8].Here, we report our experience treating a young boy with NCS.Case Reports An 8 years old boy was admitted with a two months history of hematuria and left flank pain.Urine analysis revealed that the patient had gross hematuria and pyuria.His renal function tests were normal.Hemogram revealed low hemoglobin.He was given intravenous antibiotics.USG abdomen showed bright echotexture in bilateral kidneys with decreased cortico-medullary differentiation.Left kidney was bulkier than right one.He was discharged from hospital on oral antibiotics but after two weeks the patient's symptoms recurred.He was again admitted.CT abdomen was done which showed significant decrease in aortomesenteric angle measuring 22 degrees and aorto-mesenteric distance measuring 5 mm [Fig.1] causing compression of LRV between SMA and aorta.Dilatation of renal vein was seen before compression with small hypodense filling defect within suggestive of thrombus.

Fig. 1 .
Fig. 1.CT abdomen showing stenosis of the left renal vein between the superior mesenteric artery and the aorta (black arrow) with proximal dilatation of the left renal vein (white arrow).