Nutcracker phenomenon (NP) is defined as the compression of the left renal vein, often occurring between the aorta and the superior mesenteric artery (SMA). Patients with symptoms associated with the Nutcracker anatomy are called “Nutcracker syndrome” (NCS). Renal vein compression results in venous congestion, outlet obstruction, and increased pressure in the left renal vein. The clinical manifestations of NCS in children vary widely depending on the severity of compression. It can range from being asymptomatic to presenting with intermittent or persistent micro or macrohematuria, orthostatic proteinuria, renovascular hypertension, abdominal pain, left-sided flank pain, dysmenorrhea, pain in the testicles or scrotum, and left varicocele. Hematuria, proteinuria, and flank pain are prevalent symptoms. The anatomical and physiological degree of compression of the left renal vein can be diagnosed through Doppler ultrasound (DUS), computer tomography (CT) scan, or magnetic resonance imaging (MRI). In cases with mild symptoms, conservative treatment is an appropriate option, and ACE inhibitors can be used for patients with proteinuria. In more severe cases where conservative approaches and medical treatment fail to yield satisfactory results, endovascular, laparoscopic, or open surgical interventions are employed.

Keywords: Nutcracker phenomenon, Nutcracker syndrome, left renal vein entrapment, hematuria, orthostatic proteinuria