Nutcracker syndrome precautions

The nutcracker phenomenon is also called left renal vein stress, which refers to the left renal vein being squeezed and formed in the angle formed by the abdominal aorta and the superior mesenteric aorta or the space between the abdominal aorta and the spine during the whole process of returning to the inferior vena cava. It is often accompanied by a decrease in the blood velocity of the left renal vein and dilation of the vein distal to the stress point. When the nutcracker phenomenon causes a series of clinical manifestations such as hematuria, proteinuria and left waist and abdominal pain, it is called nutcracker syndrome.

Under normal circumstances, the left renal vein passes through the intersection between the abdominal aorta and the superior mesenteric aorta, passes in front of the abdominal aorta and enters the inferior vena cava. This intersection angle is about 45° to 60°, and is filled by mesenteric fat, lymph nodes, retroperitoneum and sympathetic nerve plexus, so that the left renal vein is not stressed. In patients with nutcracker phenomenon/nutcracker syndrome, this intersection angle is generally less than 16°.

Most patients with Nutcracker syndrome present with hematuria with or without lumbago. The vast majority of patients are tall adolescents and children. Clinical symptoms include standing proteinuria and varicose veins of the left flexor vein in men. Some middle-aged and elderly female patients may present with hematuria and pelvic congestion syndrome.

The nutcracker phenomenon is often discovered due to sudden gross hematuria. Microscopic hematuria without symptoms is often found during urine examination. The current medical history includes multiple and recurrent gross hematuria, which sometimes lasts for several months or more than a year. Hematuria often occurs during excessive exercise and fever and cold. It may be accompanied by general fatigue, left abdominal pain, left waist discomfort and pain. When other causes such as tumors, inflammation, stones, hypercalcemia and renal parenchymal damage are excluded, the possibility of the nutcracker phenomenon should be fully considered and can be combined with urinary system MRI diagnosis. Mild asymptomatic cases do not affect pregnancy.

For patients with long-term persistent gross hematuria, if there is no anemia, the development trend of the disease can be observed, no further treatment is needed, and regular follow-up is required. Patients with surgical indications should actively adopt surgical treatment in the early stage to eliminate the compression of the left renal vein. Patients with more than 2 years of observation or medical medication, no improvement or aggravation of symptoms; patients with symptoms such as anemia, flank pain and varicose veins, repeated fatigue, headache, anxiety, etc., which have affected learning or daily life, or patients with renal function damage, and other causes have been eliminated, should consider surgical treatment.