Effectiveness of supine/standing urinalysis for differential diagnosis of left renal vein entrapment syndrome combined with or without glomerulopathy

Diagnostic Clues in Pediatric Nutcracker Syndrome: From Two Clinical Cases to Current Literature Analysis

Nutcracker syndrome (NCS) is a rare pediatric disease caused by left kidney vein compression. Besides the "Triade's symptoms", including hematuria, proteinuria, and flank pain, a wide spectrum of clinical manifestations has been reported. As the significant hemodynamic changes secondary to the dilatation of the left renal vein, serious consequences such as renal vein thrombosis and severe anemia might occur in these children. NCS diagnosis includes a variety of invasive and non-invasive imaging tools, but cutoff values need to be further validated. A conservative treatment represents the most common therapeutic approach for these patients, but operative options are available in selected cases. To complicate matters, a standard diagnostic and treatment algorithm is currently lacking and scientific pediatric evidence in this field is still poor and limited. In this perspective, early recognition of NCS is crucial but challenging for pediatricians. Therefore, a better knowledge of the disease is recommended. Starting from two different clinical presentations of NCS, we aimed to provide a comprehensive overview of the disease in children.

Left renal vein entrapment in postural proteinuria: the diagnostic utility of the aortomesenteric angle

Nutcracker syndrome related to the left kidney vein compression is a cause of orthostatic proteinuria during childhood. Some studies have shown that the ratios between maximum velocities and anterior-posterior diameters of hilar and aortomesenteric segments of the left kidney vein between upright and supine positions must be more than 4 in order to make a Nutcracker syndrome diagnosis. Our aim was to investigate whether the use of a decrease in aortomesenteric angle between upright and supine positions in the presence of isolated orthostatic proteinuria can be a criterion for the diagnosis of Nutcracker syndrome. Relevant patient information, which included demographic data, clinical examination findings, laboratory data, urinary system ultrasound, and kidney color flow Doppler ultrasound results, were prospectively collected. Thirty-nine pediatric patients with orthostatic proteinuria were included in the study. Left kidney vein compression findings were demonstrated in 31 patients. The ratio of maximum velocities of hilar and aortomesenteric segments of the left kidney vein between upright and supine positions was above 4 in only 7 of our patients. Ratio of aortomesenteric angle between upright and supine positions was significantly decreased for patients with left kidney vein compression findings.  Conclusion: The use of a decrease in the ratio of aortomesenteric angle between upright and supine positions in the presence of orthostatic proteinuria, instead of the ratios for maximum velocities and anterior-posterior diameters of hilar and aortomesenteric segments, can be more helpful for the diagnosis of Nutcracker syndrome in the differential diagnosis of orthostatic proteinuria. What is Known: • Proteinuria may be a sign of an impending kidney disease • Nutcracker syndrome is a cause of orthostatic proteinuria. What is New: • Ratio of aortomesenteric angle between upright and supine positions > 0.6 can be used for Nutcracker syndrome diagnosis.

Left Renal Vein Stenting in Nutcracker Syndrome: Outcomes and Implications

Nutcracker syndrome refers to the symptomatic extrinsic compression of the left renal vein presenting most commonly as flank pain and haematuria. While surgery remains the first-line treatment, stenting is gaining more acceptance and there are now several published case series. This article highlights the outcomes of left renal vein stenting in the setting of nutcracker syndrome.

Association Between Left Renal Vein Entrapment and Varicocele Recurrence: A Cohort Study in 3042 Patients

The recurrence rates after varicocelectomy vary from 0.9% to 32.2%, especially for patients with the left renal vein entrapment (LRVE). This study aims to study the association between LRVE and varicocele recurrence, and to find the risk factors of LRVE. With the design of a cohort study, we included 3042 varicocele patients who would undergo modified inguinal microscope-assisted varicocelectomy (MHMV). 858 (28.21%) patients with LRVE were as the study group, and 2184 (71.79%) patients without LRVE were as the control group. Compared with the control group, BMI was lower (p < 0.001) in study group. Totally, 18 patients had recurrence after surgery, so the recurrence rate was 0.59%. Seventeen patients (1.98%) in study group and 1 patients (0.05%) in control group had recurrence, and significant statistical difference was found between the two groups (p < 0.001). The risk ratio of LRVE for varicocele recurrence is 43.27. In conclusion, the recurrence rate of our MHMV is the lowest (0.59%). There is association between LRVE and varicocele recurrence, and varicocele patients with LRVE have higher probability of recurrence rate after varicocelectomy. BMI could be a risk factor of LRVE. Thus, for varicocele patients, especially those with lower BMI, attentions should be payed to LRVE.

Nutcracker syndrome: A rare cause of left flank pain that can also manifest as unexplained pelvic pain

Nutcracker syndrome (NCS) is symptomatic unilateral renal venous hypertension due to compression of the left renal vein between the superior mesenteric artery and aorta (anterior NCS) or between the aorta and spine (posterior NCS). The left ovarian or spermatic vein empties into the left renal vein and is an additional site of venostasis in about half the cases of NCS. The presenting symptom of NCS in about half the cases is atypical left flank pain suggesting a disorder of the lower ribs or thoracolumbar spinal junction, particularly as the pain worsens with standing and increased lumbar lordosis. NCS may be suggested by any combination of the following manifestations: hematuria, which is often only microscopic; orthostatic proteinuria; varicocele and infertility; dyspareunia and other gynecological symptoms; varicose veins in the pelvis, buttocks, or upper thighs; orthostatic hypotension and fatigue; and abdominal pain. Narrowing of the left renal vein on imaging studies is required but far from sufficient to establish the diagnosis. Several converging clinical findings and a marked pressure gradient between the left renal vein and inferior vena cava must be present also. Urological procedures and vascular surgery are being superseded by endovascular stenting with or without simultaneous treatment of the acquired gonadal vein insufficiency by embolization.