What is Nutcracker Syndrome, also known as Left Renal Vein Entrapment (LRV) syndrome?

From the Guidelines

Nutcracker syndrome is a rare vascular condition characterized by the compression of the left renal vein between the abdominal aorta and the superior mesenteric artery, leading to restricted blood flow and increased pressure in the left renal vein. This condition is typically diagnosed through imaging studies such as Doppler ultrasound, CT angiography, or MRI, and patients often experience symptoms like left flank pain, hematuria, and pelvic congestion symptoms 1. The treatment of nutcracker syndrome has evolved, with percutaneous endoluminal left renal vein stenting now being performed as an alternative to open surgery, although its benefits are mostly limited to remission of pelvic venous symptoms 1. Some key points to consider about nutcracker syndrome include:

• The condition is caused by anatomical variations in the branching of the superior mesenteric artery from the aorta
• Symptoms can include left flank pain, hematuria, and pelvic congestion symptoms like painful periods in women or varicoceles in men
• Treatment depends on symptom severity, ranging from observation and pain management for mild cases to surgical intervention like renal vein transposition, stent placement, or bypass procedures for more severe cases
• Weight loss can sometimes worsen symptoms by reducing the fat padding between the blood vessels
• Recent studies, such as those published in the Journal of the American College of Radiology 1, have highlighted the role of left renal vein stenting in managing pelvic venous disease due to nutcracker syndrome.

From the Research

Definition and Causes of Nutcracker Syndrome

• Nutcracker syndrome (NCS) is caused by compression of the left renal vein between the abdominal aorta and the superior mesenteric artery 2, 3, 4, 5, 6.
• This compression leads to a series of clinical symptoms, including hematuria, proteinuria, flank pain, and varicocele 2, 3, 4, 5, 6.

Clinical Symptoms of Nutcracker Syndrome

• The symptoms of NCS vary from asymptomatic hematuria to severe pelvic congestion 3.
• Common symptoms include hematuria, orthostatic proteinuria, flank pain, abdominal pain, varicocele, dyspareunia, dysmenorrhea, fatigue, and orthostatic intolerance 3, 4, 5.
• The frequency of symptoms is as follows: 78.57% for hematuria, 38.39% for left flank pain, 35.71% for varicocele in males, 30.36% for proteinuria, and 13.39% for anemia 4.

Diagnosis of Nutcracker Syndrome

• The diagnosis of NCS is difficult due to variations in normal anatomy 2.
• Several imaging methods are used to diagnose NCS, including Doppler ultrasonography, computed tomography angiography, magnetic resonance angiography, and retrograde venography 3, 5, 6.
• Intravascular pressure measurements are often required to prove a renocaval pressure gradient and aid in a definitive diagnosis 5.

Treatment Options for Nutcracker Syndrome

• The management of NCS depends on the clinical presentation and the severity of the left renal vein hypertension 3.
• Treatment options range from surveillance to nephrectomy 2, 3.
• Conservative management is appropriate, especially in children, who tend to outgrow the disorder 5.
• Invasive therapies, such as renal vein transposition and endovascular stenting, are more frequently pursued in adults 5.