What Is the Difference Between Low Back Pain and Kidney Pain?
Low back pain is one of the most commonly reported health concerns in the United States, affecting millions of people each year. In most cases, the pain is caused by overuse, poor posture, a muscle strain or another musculoskeletal condition rather than a serious underlying illness. Still, because the kidneys are located toward the back of the abdomen, just below the rib cage on either side of the spine, it can sometimes be difficult to tell whether pain is coming from the spine and surrounding muscles or from the kidneys themselves.
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A key difference is where the pain originates. Low back pain typically affects the lumbar region of the spine and surrounding muscles and may worsen with certain body positions or movements. In contrast, kidney pain is usually felt in the flank, which is the area beneath the lower ribs on either side of the spine. Kidney pain often feels deeper and may be less affected by changes in position or movement.
Kidney pain can have many causes, including relatively common conditions such as urinary tract infections (UTIs) and kidney stones. Kidney cancer is a much less common cause of back or flank pain, but persistent or unexplained symptoms should be evaluated by a physician. At Moffitt Cancer Center, patients with atypical imaging findings or other concerns about kidney cancer have access to timely diagnostic evaluations, advanced imaging technology and specialists with extensive expertise in diagnosing and treating kidney tumors.
How can I tell at home if my pain is low back pain or kidney pain?
One helpful way to distinguish between low back pain and kidney pain is to pay attention to how the discomfort responds to movement. Musculoskeletal low back pain often changes throughout the day. For instance, it may worsen with bending, twisting, lifting or remaining in the same position for too long. It may also improve with brief rest, stretching or changing positions. The discomfort is frequently accompanied by muscle tightness or stiffness.
Kidney pain is generally less closely linked to body position or movement. Depending on the cause, it may feel like a steady, deep ache or, in the case of a kidney stone, intense pain that comes and goes in waves. Unlike musculoskeletal pain, kidney pain may also occur along with urinary symptoms, fever, nausea or other signs of illness.
While noting how the pain responds to movement can provide helpful clues, it cannot reliably determine where the pain originates or what is causing it. If symptoms continue or are accompanied by other concerning signs, it is important to seek a professional medical evaluation.
Does kidney cancer always cause low back or flank pain?
No. In fact, many people with early-stage kidney cancer have no symptoms at all.
As imaging tests such as computed tomography (CT) scans and ultrasounds have become commonplace, an increasing number of kidney tumors are discovered incidentally during an evaluation of an unrelated medical concern. This means kidney cancer is often diagnosed before it causes pain or other noticeable symptoms.
When kidney cancer does produce symptoms, they may develop as a tumor grows or affects nearby structures. Although persistent flank pain deserves medical attention, it is important to remember that the vast majority of back pain cases are unrelated to kidney cancer.
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Schedule an AppointmentWhat color does urine turn when the kidneys are struggling?
Urine does not turn a specific color when the kidneys are not functioning normally. In fact, kidney problems can occur without any visible change in urine. However, certain changes in urine color or appearance can signal a urinary tract or kidney problem.
One important warning sign is blood in the urine (hematuria), which is also a possible symptom of kidney cancer. Depending on the amount of blood present, urine may appear pink, red, rust-colored or brown. In other cases, the urine may look normal and blood is detected only through laboratory testing.
Blood in the urine does not necessarily mean kidney cancer is present. UTIs, kidney stones and several other noncancerous conditions can also cause hematuria. However, unexplained blood in the urine should be evaluated promptly.
When should I see a doctor for flank pain?
Most episodes of low back pain improve within a few days to a few weeks with conservative measures, such as modifying activities, staying gently active and using over-the-counter pain relievers when appropriate. Flank pain warrants professional medical attention if it:
- Persists or does not improve
- Continues to worsen
- Repeatedly returns without a clear cause
- Does not improve with home care
It is important to seek immediate medical attention for sudden, severe flank pain that is difficult to tolerate or accompanied by:
- Blood in the urine
- Inability to urinate
- Fever or chills
- Severe nausea or vomiting
Prompt evaluation can help determine whether the cause is a kidney infection, kidney stone or another condition requiring treatment.
When could flank pain be related to kidney cancer?
Kidney cancer is an uncommon cause of flank pain, and many kidney tumors cause no symptoms in their early stages. If pain develops, it may be persistent and affect one side of the back or flank.
Other symptoms of kidney cancer
In addition to flank pain, possible signs and symptoms of kidney cancer include:
- Blood in the urine
- A lump or fullness that can be felt in the side or abdomen
- Recurrent or unexplained fevers
- Unintentional weight loss
- Ongoing fatigue
Having one or more of these signs or symptoms does not necessarily mean kidney cancer is present. However, persistent or unexplained flank pain, particularly when accompanied by urinary changes or other concerning symptoms, should be evaluated by a physician, who may recommend imaging tests to help determine the underlying cause.
Possible back-related symptoms
Symptoms more commonly associated with musculoskeletal back pain include:
- Pain that changes with movement or posture
- Muscle spasms or stiffness
- Pain after lifting, exercise or an injury
- Tenderness in the muscles of the low back
- Numbness, tingling or pain that radiates into the leg, which may suggest a spinal or nerve condition rather than a kidney problem
The Moffitt Cancer Center difference for kidney cancer
Most cases of low back or flank pain are not caused by kidney cancer, but persistent or unexplained symptoms deserve careful evaluation. At Moffitt, our urologic oncology specialists use advanced imaging and other diagnostic testing to evaluate suspicious kidney findings. When cancer is diagnosed, our multispecialty team develops an individualized treatment plan based on the patient’s specific needs.
To learn more about kidney cancer symptoms and treatment, you can request an appointment with a specialist in Moffitt’s Urologic Oncology Program by calling 1-888-663-3488 or submitting a new patient registration form online. We do not require referrals.