Evaluation of Anterior Nutcracker Syndrome in Children: One Center Experience

Objective: Nutcracker syndrome (NCS), caused by the compression of the left renal vein (LRV) between the superior mesenteric artery (SMA) and the abdominal aorta, is a rare clinical condition. While renal Doppler ultrasonography has been used to diagnose NCS, there have been few studies linking LRV compression measurements to symptoms in pediatric patients. This long-term retrospective study aimed to evaluate the clinical characteristics of NCS and its Doppler ultrasonographic measurements in children. Material and Methods: Demographic, clinic, and laboratory data were collected from the medical records of patients with NCS. All renal Doppler ultrasonography (DUS) findings of the study population were also reviewed. Results: A total of 50 patients with NCS were identified with a mean follow-up of 6.3 years. The proportion of proteinuria was 70%, and 36% of the patients exhibited symptoms of hematuria. Varicocele was also observed in 55.5% of male patients. While patients with hematuria were diagnosed earlier, patients with varicocele and proteinuria were diagnosed later in life. The mean SMA angle of patients in the supine position was significantly lower patients with varicocele (23.80±3.04° vs 27.87±4.49°, p=0.049). The estimated glomerular filtration rate (eGFR) did not differ in patients with hematuria and in patients with variocele. On the other hand, patients with proteinuria had a lower eGFR than those without (129.85±18.48 ml/min/1.73 m² vs 141.82±20.72 ml/min/1.73 m², p=0.030). The Doppler ultrasonographic parameters of the LRV did not change according to the gender, but the SMA angle decreases significantly with aging. Conclusion: Although hematuria seems to be common, proteinuria is also common in NCS and SMA angle should thought to be important in children with varicocele.