Flank Pain

Flank pain affects one or both sides of the body between your abdomen and back. This symptom can be caused by issues with your muscles, internal organs, or your spine. Physical examination and imaging are often performed to determine the cause of flank pain.

This article will discuss the symptoms of flank pain and the possible causes, diagnosis, and treatment of these conditions.

Vascular Emergency

Sudden-onset flank pain may be caused by a serious problem with the blood vessels. While uncommon, these issues are serious and require immediate medical care. Examples of vascular emergencies include aortic dissection and acute aortic aneurysm.

Symptoms

An aortic dissection occurs when the body's major artery, the aorta, is damaged. When the wall of the aorta tears, blood flows into the layers of the blood vessel walls. This can lead to an aortic rupture or a lack of blood to the organs.

Symptoms of an aortic dissection may include:

• Sharp, stabbing pain
• Pain moving from the chest to the shoulder blades to the flank area.
• Nausea and vomiting
• Fainting
• Sweating
• Rapid, weak pulse
• Shortness of breath

Causes

An aortic dissection is caused by a tear in the lining of the aorta. This can lead to an abnormal widening of the aorta, known as an aortic aneurysm.

Diagnosis

An aortic dissection and aneurysm are medical emergencies and require immediate evaluation and treatment. Your healthcare provider will start with a physical exam and listen to your heart with a stethoscope.

Diagnostic tests may include:

• Aortic angiography: A test to visualize blood flow in the body
• Chest X-ray
• Chest computed tomography (CT scan)
• Chest magnetic resonance imaging (MRI)
• Echocardiogram: An ultrasound test to observe the heart
• Blood tests to rule out a heart attack

Treatment

An aortic dissection requires immediate treatment with either surgery or medications, depending on where the tear is. An aortic aneurysm is also treated with surgery or medications.

Muscle Strain or Spasm

Flank pain can be caused by injury or spasms in the muscles. Flank muscles include the internal and external oblique abdominal muscles that help to rotate and flex your spine forward and side to side, as well as lumbar (low back) muscles that help you stand up from a bent-over position.

Symptoms

Muscle strains can develop over time from repetitive movements. This causes micro-tearing of the muscle fibers. Sudden movements that strain your muscles can also lead to immediate symptoms of muscle strain.

Symptoms can include:

• Pain in your side or low back
• Spasms (involuntary contractions) in the affected muscles
• Decreased range of motion
• Stiffness
• Pain when the muscles are touched
• Knots in the muscle
  

With severe muscle injury, you might also have swelling or bruising in the affected area.

Causes

Oblique abdominal muscle injuries are common in athletes who participate in explosive movements with one side of the body, such as throwing. Lumbar strains typically occur with pushing, pulling, or sudden twisting movements. Damage to these muscles can also be caused by trauma, such as a fall.

Diagnosis

Muscle strains are often diagnosed based on the history of your symptoms and a physical exam by your healthcare provider. Additional tests are not usually needed to make this diagnosis.

Treatment

Muscle strains often improve with rest from aggravating activities and home remedies. These can include:

• Ice packs
• Heat packs (after 72 hours when inflammation has decreased)
• Massage
• Gentle stretching
• Range of motion exercises (without pain)
• Physical therapy

Medications can also help relieve symptoms, such as:

• Over-the-counter (OTC) pain reliever: Tylenol (acetaminophen) is a common example of this type of medication.
• Non-steroidal anti-inflammatory drugs (NSAIDs): These medications help decrease inflammation and swelling, which can also help relieve pain. Examples include Aleve (naproxen) and Advil (ibuprofen).
• Muscle relaxers: These drugs decrease muscle spasms. Examples include Skelaxin (metaxalone) and Flexeril (cyclobenzaprine).

Spine Conditions

Conditions that affect the spine can also cause flank pain. These can include lumbar arthritis, spinal stenosis, and disc degeneration. In some cases, these conditions can compress nerves in the lumbar spine that supply your legs.

Symptoms

In addition to flank pain, other symptoms of spine conditions can include:

• Pain that radiates down the buttocks or leg
• Numbness or tingling in the buttocks or leg
• Stiffness (particularly after periods of time sitting still)
• Muscle spasms
• Muscle weakness

Causes

Many lumbar spine conditions that lead to flank and lower back pain are caused by "wear and tear" on the body as a person ages. Bone spurs can develop between the vertebrae in the spine, and discs (cushions between the vertebrae) become thinner.

Lumbar disc degeneration often causes symptoms around the age of 40 and is particularly common in people who have jobs that require repetitive movements, such as office workers, machine operators, and carpenters.

Diagnosis

Diagnosis of spine conditions begins with a thorough history of your symptoms and a physical exam by your healthcare provider. Additional tests, such as X-rays, computed tomography (CT scans), and magnetic resonance imaging (MRIs) are often performed to determine the exact cause of your symptoms.

Treatments

Home remedies and OTC medications are used to help relieve symptoms of spine conditions. Sometimes, steroid anti-inflammatory medications are injected into the affected area.

When conservative treatment is not effective, surgery may be recommended to treat spine conditions.

Urinary System Conditions

Flank pain is often a symptom of conditions that affect the urinary system, including kidney stones and infections.

Symptoms

Flank pain is a primary symptom of kidney stones and urinary infections.

Other symptoms can include:

• Fever
• High heart rate
• Nausea
• Vomiting
• Blood in urine
  

Kidney stones are hard deposits that can develop in the kidneys. These stones can leave the kidney and travel through the ureter to your bladder, and out of your body. Flank pain often occurs when a kidney stone enters the ureter. This pain is sudden and severe.

Flank pain from infection can develop more gradually.

Diagnosis

Blood and urine tests are used to help diagnose urinary issues. If you have kidney stones, blood tests can help determine the specific minerals that make up your stones. Urine tests assess levels of white blood cells, which can indicate if an infection is present.

Your healthcare provider may also recommend an ultrasound if kidney stones are suspected. Imaging such as X-rays and CT scans are also used to diagnose kidney stones.

Treatment

Urinary infections are typically treated with antibiotic medications. Treatment of kidney stones depends on the size of the stone. Small stones often pass on their own without any additional treatment.

Larger kidney stones can require additional treatment. Interventions include:

• Shock wave lithotripsy: This is a condition that uses high-energy shock waves to break large kidney stones into smaller pieces that can pass through the urinary system.
• Scope procedures: In some cases, a urologist will use a thin scope device to find and remove kidney stones that are stuck in different parts of your urinary system.
• Percutaneous nephrolithotomy: This is a surgical procedure that involves inserting a tool into the kidney through the skin on your back to remove a stone, or break up a large stone using a laser.
  

Shingles

Shingles (Herpes Zoster) is a viral condition that can cause flank pain.

Symptoms

The primary symptom of shingles is a painful, itchy rash on one side of the torso or face.

Other symptoms of shingles include:

• Fever
• Nausea
• Headache
• Chills
• Skin sensitivity
• Burning sensation
• Numbness or tingling

Diagnosis and Treatment

Shingles is diagnosed through a physical exam by a healthcare provider. A skin swab might be sent to a lab to confirm your diagnosis.

There is no cure for shingles, but symptoms can resolve on their own without treatment. Sometimes, antiviral medications are used to help reduce the severity of symptoms.

Summary

Flank pain can be a symptom of conditions that affect your muscles, lumbar spine, or internal organs. Common causes of flank pain include muscle strain, lumbar spine arthritis, and kidney stones. These conditions are diagnosed through a physical exam, lab tests, and imaging.

Treatment for flank pain depends on the underlying cause. Sometimes flank pain can resolve with rest and home remedies, while other causes might require surgery.

A Word From Verywell

Flank pain is a symptom that can indicate a wide variety of medical conditions. If you know what caused your flank pain, such as a muscle strain after lifting a heavy object, it might be appropriate to treat your symptoms at home.

However, some causes of flank pain are more serious and require medical treatment. When in doubt, see a healthcare provider (sooner than later) to determine the cause of your flank pain.