Back pain is among the top reasons people call their doctors. Pain in your upper back or abdomen and sides, also called flank pain or kidney pain, has numerous causes.
What Causes Flank Pain?
If you have persistent pain, you should always consult your physician. However, flank pain most commonly results from one of three causes:
- Urinary tract infection (UTI).
- Kidney stones.
- Musculoskeletal problems, such as a muscle strain or pinched nerve.
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Urinary Tract Infection (UTI)
A urinary tract infection (UTI) is caused by bacteria that enters the urinary tract, which includes the kidneys, bladder, ureters, and urethra.
Symptoms of a UTI
Pain in your lower back or abdomen may be a sign of a lower UTI, such as an infection in the bladder. Pain in the upper back and kidney area may be a sign of an upper UTI.
Other UTI symptoms include:
- A frequent urge to urinate.
- Burning when you urinate.
- Blood in the urine.
UTI Risk Factors
Due to anatomical build, women are at a much higher risk of developing UTIs than men. Outside of biological sex, here are a few factors that can put you at a higher risk of developing a UTI:
- Sexual activity
- Birth control
- Personal hygiene
Your primary care doctor or an urgent care doctor can treat a UTI. You’ll be prescribed an antibiotic, and symptoms should clear up shortly afterward. For recurring or severe UTIs, your doctor may refer you to a urologist.
Kidney stones are crystals that form in your urine and build up in your kidneys. They cause severe pain.
Symptoms of kidney stones
Kidney stones cause sudden, severe flank pain that can come in waves. The pain also may radiate down through the groin. The pain continues as the stone travels through the ureters, the bladder, and out the urethra if it’s small enough.
You also may experience:
- Blood in the urine.
- Nausea or vomiting.
- Painful urination.
Kidney Stone Risk Factors
Kidney stones can cause intense and radiating flank pain. Here are the factors that can increase your risk of developing kidney stones:
- High-sodium diet.
- Family history of kidney stones.
- Chronic UTIs.
Kidney Stone Prevention
The kidneys are your body’s filters. The waste from your kidneys travels out of your body through urine. One of the best ways to prevent common kidney problems is to drink plenty of water. This helps keep the filtering process running smoothly.
Kidney Stones Treatment
For small stones, you can take pain medications and drink lots of water until the stone passes. Your doctor also may prescribe a medication to help you pass the stone if you have trouble passing it on your own.
Large stones that cannot fit through the urinary tract need to be removed by surgery or lithotripsy, a procedure that breaks apart large stones into small pieces that can pass.
What is Musculoskeletal Pain?
Sometimes, flank pain can be traced to a musculoskeletal problem. Muscle-related pain will feel more like a dull ache and usually worsens with physical activity, pressure, or actions that use those muscles like sneezing or laughing.
You may also have flank pain from spinal arthritis or a pinched nerve.
To treat the pain at home, use non-steroidal anti-inflammatory drugs like ibuprofen, and ice the area for about 20 minutes at a time every few hours. If the pain doesn’t go away, or you notice swelling or redness along your sides, call your doctor or visit an urgent care center.
Musculoskeletal Pain Risk Factors
This type of pain could be caused by a muscle strain or tear due to:
- Increased physical activity.
- A fall or other trauma.
- Lifting something too heavy.
- Repetitive motion.
Other Causes of Flank Pain
Flank pain can sometimes be caused by other, more serious conditions. These include:
- Bladder or kidney cancer.
- Kidney disease.
- Gallbladder disease.
- Blockage in the urinary tract.
When to see a doctor
Flank pain can be tricky to diagnose and require a few different tests to pinpoint the problem. It’s always best to talk to your primary care doctor if you have unexplained pain that doesn’t go away. You should also call your doctor right away if you have signs of an infection, such as fever, fatigue, or body aches.
Visit the UPMC Department of Urology to learn more about these conditions, which may result in flank pain or to schedule an appointment with one of our urologists.
Editor's Note: This article was originally published on , and was last reviewed on .
The UPMC Department of Urology offers a wide variety of specialized care for diseases of the male and female urinary tract and the male reproductive organs, including erectile dysfunction, kidney stones, urinary incontinence, prostate cancer, and more. We have a multifaceted team of physicians and researchers working together to provide the best care to both children and adults. Our team is nationally renowned for expertise in highly specialized technologies and minimally invasive surgical techniques. To find a provider near you, visit our website.