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Nutcracker Syndrome

Nutcracker syndrome is a rare vein compression disorder. It occurs when arteries, most often the abdomen’s aorta and superior mesenteric artery, squeeze the left renal (kidney) vein.

It can cause many symptoms in both children and adults, such as flank pain and blood in the urine. Common treatments for nutcracker syndrome include stenting, surgery, and routine urine tests.

At the UPMC Heart and Vascular Institute, our surgeons in the Division of Vascular Surgery are experts in treating nutcracker syndrome using the latest techniques. We take a team approach to diagnose your condition and design a treatment plan that’s right for you.

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What Is Nutcracker Syndrome?

Nutcracker syndrome is a variation of nutcracker phenomenon or renal vein entrapment syndrome, in which the arteries near the kidney compress the left renal (kidney) vein.

In most cases, compression of the left renal vein is between the abdominal aorta — the main artery in the abdomen — and the superior mesenteric artery, which brings blood to the pancreas and intestines. Nutcracker syndrome gets its name because this compression is like a nutcracker crushing a nut.

Normally, the left renal vein brings blood out of the left kidney and into the inferior vena cava, the body’s largest vein.

Compression of the left renal vein can cause blood to flow backward into other nearby veins and make them swell. This causes symptoms like flank pain and blood in urine.

Nutcracker syndrome risk factors and causes

Nutcracker syndrome is a rare disorder that can affect adults or children, though the prevalence and specific causes are unknown.

It's more common in women in their 30s and 40s who are tall and slim. Symptoms may appear after rapid weight loss.

Most people with nutcracker syndrome have abdominal pain but this condition can be present — especially in children — without any symptoms. Nutcracker syndrome is not hereditary, though it may be triggered by multiparity or pregnancy.

Why choose the UPMC Division of Vascular Surgery for nutcracker syndrome care?

The experts in UPMC’s Division of Vascular Surgery have substantial experience in diagnosing and treating nutcracker syndrome

Learn More About Nutcracker Syndrome

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Nutcracker Syndrome Symptoms and Diagnosis

Nutcracker syndrome symptoms

Nutcracker syndrome has many symptoms for both adults and children, although some – especially children – don’t have any symptoms.

The most common symptoms of nutcracker syndrome can include:

  • Flank pain (abdominal pain).
  • Blood in urine (hematuria).
  • Pelvic congestion in women, or varicose veins in the lower abdomen that may cause pain and heaviness in the pelvis or genital area.
  • In women, pain during sexual intercourse.
  • In men, varicoceles (enlarged veins in the scrotum).

Other symptoms of nutcracker phenomenon can include:

  • Varicose veins in the legs.
  • Severe menstrual cramping.
  • Painful urination.
  • Gluteal and vulvar varicose veins.
  • Low energy.

Nutcracker syndrome diagnosis

Nutcracker syndrome can be challenging to diagnose because its symptoms can be like other urologic or gynecologic disorders.

Doctors often diagnose nutcracker syndrome after ruling out other conditions.

To diagnose nutcracker syndrome, your UPMC doctor will:

  • Talk with you about your symptoms.
  • Review your medical history.
  • Perform a physical exam.

Your UPMC doctor will also take any physical abnormalities or differences into account when diagnosing nutcracker syndrome.

To rule out other common renal conditions, your doctor will perform the following in order:

  • Blood exam
  • Urinalysis
  • Urine culture
  • Cytology
  • Urethrocystoscopy
  • CT urography
  • Renal biopsy

To confirm a nutcracker syndrome diagnosis, your doctor may order tests such as:

  • Doppler ultrasound — a common test that uses ultrasound waves to make pictures of the blood flowing through your veins.
  • CT scan — that uses cross-sectional x-rays and a computer to create detailed 3D images.
  • MRI — that uses a large magnetic field, radio waves, and computers to create detailed images of your veins. 

Learn More About Nutcracker Syndrome Symptoms and Diagnostic Testing

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Nutcracker Syndrome Treatment

Nutcracker syndrome treatments can vary based on your age, symptoms, and the severity of your condition.

In some cases, you may not need treatment, particularly if you're:

The most common treatments for nutcracker syndrome are:

  • Stenting
  • Surgery
  • Routine urinalysis

Your UPMC doctor will discuss each option with you.

Stenting for nutcracker syndrome

Your surgeon may choose to treat your nutcracker syndrome using a stent — a small mesh tube — to hold your left renal vein open and allow for proper blood flow.

To place the stent in your vein, your surgeon will:

  • Make a small puncture in your leg.
  • Insert a catheter — a thin, flexible tube — and a guide wire into your vein to put the stent in the right place.
  • Expand the stent, which will hold your vein open.

In most cases, you’ll stay in the hospital overnight after the procedure.

Nutcracker syndrome surgery

In some severe cases of nutcracker syndrome, your doctor may suggest vascular surgery to relieve the pressure on your left renal vein.

Surgical treatment for nutcracker syndrome can include moving the left renal vein and reattaching it, or a left renal vein bypass.

Your doctor may recommend surgical treatment of nutcracker syndrome for the following reasons:

  • Persistent or recurrent blood in the urine (hematuria) is causing anemia.
  • Blood clots are causing flank pain (abdominal pain).
  • Severe pain.
  • The condition has not improved after 24 months of monitoring.

Natural treatments for nutcracker syndrome

Some people with a mild case of nutcracker phenomenon may prefer to postpone invasive treatments and monitor the condition with regular urinalysis. If you choose this option, your doctor will track your condition with regular urinalysis.

Since this is a condition that may improve on its own with time, regular urinalysis let your doctor know if the phenomenon improves or when to take next steps.

Nutcracker syndrome recovery time and prognosis

Stenting: Recovery time for nutcracker syndrome stenting can last 2-3 months. This allows time for the body to accept the stent and for new tissue to surround it.

Surgery: Nutcracker syndrome surgery recovery time can last 3 months while the vein and/or artery heals.

In severe cases of nutcracker syndrome, pain and other symptoms are often alleviated right away. In mild cases, the improvement is less obvious. 

Learn More About Nutcracker Syndrome

From UPMC's Health Beat Blog