Nutcracker Syndrome - Types, Causes, Signs, Symptoms, Diagnosis and Treatment

What Is Nutcracker Syndrome?

Nutcracker syndrome, also known as left renal vein entrapment syndrome, is characterized by left renal vein compression. The term renal implies the kidneys, bean-shaped organs on either side of the body below the ribcage. They work to filter the blood, form urine, and maintain the fluid and electrolyte levels of the body. Normally, the kidneys have one vein that carries the blood filtered into the circulatory system. These veins are known as the renal veins, and one of them is present on the right side while the other is on the left. In addition to the veins, arteries are also near the kidneys, mainly the abdominal aorta and superior mesenteric artery. The abdominal aorta is the main artery of the stomach or the abdomen, whereas a superior mesenteric artery supplies the pancreas and the kidneys. The problem arises when these arteries compress the left renal vein from the left kidney. As a result, the blood flows back to the other and causes them to swell. This condition is known as nutcracker syndrome. It must be treated at the earliest to avoid complications.

What Are the Different Types of Nutcracker Syndrome?

Nutcracker syndrome occurs when the arteries near the kidneys or the abdomen compress the renal vein and interfere with the blood flow. The different types of nutcracker syndrome are listed in the table below:

What Are the Most Important Causes or Risk Factors of Nutcracker Syndrome?

The specific causes of nutcracker syndrome vary from person to person. Sometimes, people are born with variations in the blood vessels that can result in the symptoms of nutcracker syndrome. The symptoms of nutcracker syndrome are commonly seen in females in their 20s and 30s. The factors that increase the risk of nutcracker syndrome are listed below:

1. Pancreatic tumors increase the risk of nutcracker syndrome because the vessels supplying the pancreas become damaged and compress the renal veins, resulting in nutcracker syndrome.

2. Curvature in the lower spine.

3. Tumors in the tissues present in the inner lining of the abdominal wall.

4. Nephroptosis (a condition in which the kidneys drop into the pelvis while standing).

5. Aneurysm in the abdominal aorta.

6. Sudden changes in the weight and height.

7. Enlargement of abdominal lymph nodes.

8. Pregnancy.

What Are the Signs and Symptoms of Nutcracker Syndrome?

Nutcracker syndrome has been named because the arteries compress the veins just like a nutcracker breaks the nut. When the patient does not experience any symptoms, the condition is known as the nutcracker phenomenon. As soon as the patient starts experiencing the symptoms, the condition is known as nutcracker syndrome. The following signs and symptoms are usually noticed:

• Hematuria (blood in the urine).

• Abdominal pain.

• Pelvic pain.

• Proteinuria (protein in the urine).

• Pain during sex.

• Presence of varicose veins in the lower abdominal region. As a result, pain and heaviness in the genitals are commonly seen.

• Severe menstrual pain.

• Dysuria (painful urination).

• Low energy or light-headedness while standing.

What Tests Are Done to Diagnose Nutcracker Syndrome?

It is challenging for the doctor to diagnose nutcracker syndrome because the symptoms are similar to other urologic diseases. However, the following diagnostic methods are of great help -

• Medical History: The medical history provides insights into the patient’s general health. For example, pancreatic tumors and nephroptosis patients are more likely to develop nutcracker syndrome.

• Physical Examination: A physical examination checks abdominal pain, heaviness, and menstrual cramps. The patient will be in a distressed state and might be unable to sit or stand still due to the pain.

• Laboratory Tests: The following laboratory tests are usually recommended -

  • Urinalysis - In this test, the urine collected by the patient is examined under a microscope in the laboratory. In the case of nutcracker syndrome, high amounts of white blood cells and proteins will be present in the urine.

  • Urine Culture - Urine culture is a procedure in which the urine sample obtained from the patient is left unattended for a few days in the laboratory. If the bacteria grow rapidly, urinary tract infection can be suspected. This test helps to distinguish between nutcracker syndrome and urinary tract infections.

  • Blood Tests: A blood test is usually recommended to measure protein, creatinine, and urea levels. Both creatinine and urea are eliminated from the body by the kidneys. Therefore, if the levels of these three substances are high in the blood, renal nutcracker syndrome can be suspected.

• Imaging Tests - The most commonly used imaging tests are described below:

  • Doppler Ultrasound: Doppler ultrasound is similar to a normal ultrasound. The only difference is that blood vessels are also visible in the former, along with the internal organs. It helps detect abnormalities related to the kidneys and other urinary organs.

  • Computed Tomography (CT) Scans: These produce three-dimensional (3D) images of the body organs using computer technology and X-rays. The table on which the patient is laid slides into a tunnel-like device where the images are obtained. These images help detect abnormalities present in the kidneys and the blood vessels.

  • Magnetic Resonance Angiogram (MRA): It is a type of magnetic resonance imaging (MRI) technique that provides a detailed view of the blood vessels supplying the kidneys (kidney arteries).

What Are the Treatment Options for Nutcracker Syndrome?

The symptoms of nutcracker syndrome subside in children below 18 years. Studies have reported that no treatment is required for mild symptoms. The patient can be kept on follow-ups, and a urinalysis can be done to monitor the urine output. However, the following treatments are required when the symptoms do not subside after 18 to 24 months of care and observation:

1. Stent - The doctor might recommend the placement of a stent to treat the nutcracker syndrome. It is a small mesh tube that holds the compressed vein and opens it to allow the blood to flow normally. First, an incision is made in the legs to insert a catheter. Next, the stent is inserted into the vein with the help of the catheter. It takes several months to recover fully from the surgery. Though stenting is a simple procedure, seven percent of people have reported side effects like blood clot formation, blood vessel injury, and tear in the vessel wall.

2. Blood Vessel Surgery - If the patient has more severe symptoms, blood vessel surgery is usually indicated. Surgical options include moving the vein and reattaching it to relieve the pressure or taking the vein from other body organs.

Conclusion:

Nutcracker syndrome can affect both adults and children. Venous congestion and impaired blood supply are commonly seen in nutcracker syndrome. Sometimes, the child is born with abnormalities in the blood vessels, which might explain this disorder. The diagnosis of nutcracker syndrome is difficult because it resembles many other urinary tract disorders. Nutcracker syndrome is not a life-threatening disorder, and the condition subsides on its own in children under 18 years of age. However, the syndrome must be treated soon to avoid complications. Consult a urologist to know more about nutcracker syndrome and its treatment options.