Kashif J. Piracha, MD, is a board-certified physician with over 14 years of experience treating patients in acute care hospitals and rehabilitation facilities.
There are many reasons why you may experience kidney pain, some of which are more serious than others. The pain may be the sign of an infection, injury, or another health concern, like a kidney stone.
Because the pain is experienced inside the body, it can sometimes be confused with muscular back pain. The symptoms can also vary based on the underlying cause, ranging from a dull, creeping ache to a deeply intense pain accompanied by vomiting and fever.
This article describes the signs and symptoms of kidney pain and what the pain may suggest about the underlying cause. It also looks at how kidney pain is diagnosed and treated, and when it is time to seek medical treatment.
The kidneys are two bean-shaped organs about the size of a clenched fist that are part of the urinary tract. The urinary tract is responsible for making urine (pee) and removing it from the body.
Kidney pain, also known as renal pain , can be felt where the kidneys are located: in the middle of the back, on either side of the spine, and just under the ribcage. Sometimes, the pain will be situated on the side of the body between the upper abdomen and back, where it is referred to as flank pain.
The kidney pain may be unilateral (on one side of the body) or bilateral (on both sides). It can also be acute (rapidly developing and typically intense) or chronic (gradually developing and persistent).
Kidney pain often feels like a dull ache that gets worse when someone presses on the overlying area. However, certain conditions can trigger intense and even excruciating pain accompanied by symptoms such as:
Because the pain is often dull, it can be difficult to tell if it is arising from the kidneys or from surrounding muscles, bones, or organs. It is not uncommon for people to mistake kidney pain for back pain, although there are several key ways to tell them apart.
The pain is felt higher in the back and deep in the body.
The pain tends to be dull (although some conditions can cause sharp, stabbing pain).
The pain can be felt on one side or both sides of the back.
The pain generally will not go away if you shift your body or rest.
The pain typically is felt in the lower back.
The pain tends to be sharper and can cause shooting pains down one leg.
The pain usually will get worse with activity, such as when bending over or lifting heavy objects.
The pain can improve when you shift your body or rest.
There are many different causes of kidney pain, some of which are acute and others that are chronic. In some cases, the symptoms can hint at the underlying cause.
Kidney stones, also known as renal calculi , are among the most common causes of kidney pain. Kidney stones develop when stone fragments in the blood form clumps as they are filtered through the kidneys. The kidney pain is caused as the stone is passed downstream past the bladder to the urethra (the tube through which urine exits the body),
The pain from a kidney stone is typically severe and felt in either the back or the flank area. The pain may also be accompanied by nausea, vomiting, fever, chills, pain with urination, frequent urination, and blood in the urine.
Unlike most causes of kidney pain, the pain from kidney stones can improve as you switch positions or lie down to rest.
Urinary tract infections (UTIs) are caused by bacteria that enter the urinary tract. This not only causes pain when you urinate, known as dysuria , but can lead to fever and the need to urinate frequently.
While most UTIs affect the bladder and urethra, the infection can sometimes travel upstream and affect the kidneys as well. This type of infection is known as pyelonephritis .
Pyelonephritis can cause pain in the back, flank, or groin areas. There will often be fever and chills as well as frequent urination, burning with urination, blood in the urine, and smelly or cloudy urine. Nausea and vomiting are also common.
Dehydration (not having enough water in the body) can sometimes cause kidney pain. Dehydration can be caused by severe vomiting and diarrhea, excessive sweating or urination, or certain health conditions such as diabetes.
The kidney pain caused by dehydration tends to be dull and felt in the middle of the back on both sides. There may also be fatigue, headache, excessive thirst, sunken eyes, dizziness, reduced urination, and dark urine.
Severe cases can cause tachycardia (rapid heartbeats), tachypnea (rapid breathing), and confusion.
Dehydration can cause a buildup of wastes in the body and clog the kidneys with muscle proteins known as myoglobin . Dehydration can also contribute to the development of kidney stones and UTIs, both of which can cause kidney damage if not treated appropriately.
Sometimes the kidneys can be physically injured, such as during contact sports, a severe fall or blow, or an automobile accident. The injury, referred to as a renal contusion, can cause a dull, aching pain or sharp, stabbing pains depending on the severity of the injury.
The pain may not be immediately apparent but will often progress over the course of hours or days. In addition to pain, there may be localized bruising, tenderness to the touch, nausea or vomiting, and blood in the urine.
Kidney trauma should not be confused with acute kidney injury (AKI), a typically reversible form of kidney failure that causes the kidneys to temporarily "shut down."
Polycystic kidney disease (PKD) is a genetic disorder that causes fluid-filled cysts to form inside the kidneys. Over time, the accumulation of cysts can cause the kidneys to enlarge, triggering chronic back, side, or flank pain. Both kidneys will be affected.
Because the kidneys are involved in the regulation of blood pressure, people with PKD often have hypertension (high blood pressure). Other possible symptoms include headaches, blood in the urine, a feeling of abdominal fullness, and increased abdominal size.
People with PKD are at an increased risk of kidney stones and kidney failure.
Kidney pain is also not a typical sign of kidney failure. With kidney failure, you are more likely to feel pain in the joints and muscles than in the kidneys due to the accumulation of toxins and depletion of electrolytes in your blood.
A less common cause of kidney pain—but one that is especially important to be aware of—is kidney cancer. The most common form, called renal cell carcinoma , accounts for nine out of every 10 cases.
Kidney cancer is often asymptomatic (without symptoms) during the early stages and will often only cause symptoms when the disease is advancing.
When symptoms do develop, they often include pain in the side or flank area as well as chronic fatigue, blood in the urine, unintended weight loss, and a physical mass in the flank area.
Kidney cancer is the fifth most common cancer and the eighth most common cause of cancer-related deaths in the United States. In 2022, there were an estimated 79,000 new cases of kidney cancer in the United States and around 13,920 deaths.
There are many medications that are nephrotoxic , meaning toxic to the kidneys. Most do not cause harm when used as directed for a limited time. However, if you have underlying chronic kidney disease (CKD) or take the drugs excessively, they can injure the kidneys and cause pain.
The pain will typically be dull and felt in both kidneys. In addition to pain, there may be reduced urination, fatigue, itching, nausea, vomiting, a loss of appetite, and confusion. If the medications are not stopped, permanent kidney damage can occur.
Among the drugs that may be harmful to the kidneys are:
The treatment of kidney pain varies by the underlying cause. Some cases can be treated at home, while others require nothing more than the discontinuation of the offending drug. Others still may require aggressive treatment by a kidney specialist, known as a nephrologist .
If you have been diagnosed with a kidney stone, the treatment plan will be largely based on the size of the stone itself and includes:
UTIs are commonly treated with oral antibiotics. Uncomplicated pyelonephritis responds especially well to fluoroquinolone antibiotics but can also be treated with extended-release penicillins, cephalosporins, and Bactrim (trimethoprim-sulfamethoxazole).
The kidney pain may be eased with Tylenol (acetaminophen), gentle heat application, or taking a warm bath with Epsom salts. Ensuring ample hydration is also important.
Rehydration is the primary treatment for dehydration. This may involve oral solutions like Pedialyte for mild to moderate dehydration, while severe cases may require intravenous rehydration (in which fluids are delivered through a vein in your arm).
Drinking plenty of water can dilute the concentration of urine, which, in turn, helps relieve kidney pain. While electrolyte-rich sports drinks can be useful for milder cases of dehydration, they often contain excessive amounts of sugar that can irritate the kidneys. Rehydration with water remains the best option.
The treatment of a renal contusion is based on the severity of the injury. Milder cases often only require bed rest and supportive care with OTC painkillers, gentle heat application, and ample fluids.
Severe injuries may require angioembolization in which a flexible tube (catheter) is fed through a vein in your groin to the site of the injury to stop bleeding with jolts of electricity. Other injuries may require laparoscopic ("keyhole") surgery or open surgery to repair the damage.
Because NSAIDs promote bleeding, mild to moderate pain is often managed with non-NSAID painkillers like Tylenol. For severe pain, NSAIDs may be used with caution, either alone or with an opioid (narcotic) painkiller.
Polycystic kidney disease (PKD) is typically treated with a combination of self-care, OTC or prescription drugs, and specialist treatments like cyst aspiration (in which large cysts are drained in a minimally invasive surgical procedure).
Drinking more water also prevents the cysts from enlarging. Pain management is central to the treatment of PKD. This may involve OTC painkillers like Tylenol or Advil or stronger prescription drugs like Tylenol #3 (acetaminophen and codeine) or Ultram (tramadol).
In 2018, the Food and Drug Administration (FDA) approved Jynarque (tolvaptan), an oral medication that can slow cyst formation in people with PKD. Studies have shown that Jynarque can also reduce kidney pain in people with rapidly progressing PKD.
Renal cell carcinoma can be treated with surgery. This can reduce kidney pain even if the cancer has spread to other organs. People who cannot withstand surgery may be treated with cryosurgery (in which the tumor is destroyed with freezing) or radiofrequency ablation (in which the tumor is destroyed with electricity).
While chemotherapy and radiation therapy may be involved in the treatment plan, targeted drugs like Sutent (sunitinib) and Nexavar (sorafenib) and immunotherapy drugs like Keytruda (pembrolizumab) and Opdivo (nivolumab) have taken a more central role in the treatment of renal cell carcinoma.
Depending on the stage of cancer, the pain may be managed with opioid drugs like fentanyl, alfentanil, or sufentanil. Severe cases may benefit from morphine.
If you experience kidney pain, your healthcare provider typically will order lab tests to check for abnormalities in your blood or urine. Imaging tests will also be used to visualize the kidneys indirectly.
Other specialist procedures may directly visualize the kidneys or obtain tissue samples via a biopsy if cancer is suspected.
One of the first tests your healthcare provider will order for kidney pain is a urinalysis . The test evaluates the composition of your urine to identify signs of kidney problems, including excessive proteins or red blood cells. A urine culture can also be performed to check for bacterial or fungal infections.
Blood tests will also be ordered to evaluate your kidney function and check for signs of infection or inflammation. These typically include:
There are several imaging tests that help pinpoint the cause of kidney pain whether it be due to an infection, trauma, or disease. These include:
There are times when more invasive procedures are needed to either diagnose the cause of kidney pain or confirm the diagnosis. These include:
You should see a healthcare provider if your kidney pain is persistent or worsening. Even if the pain is dull, there is no such thing as "normal" kidney pain. It is in your best interest to have it looked at.
You should see a healthcare provider immediately if the kidney pain is accompanied by:
Seek emergency care if you develop sudden, severe kidney pain with or without blood in the urine. You should do the same if you have kidney pain and are suddenly unable to urinate. This may be a sign of a urinary tract obstruction, which can turn deadly if not treated immediately.
Kidney pain can be caused by many different things. Unlike back pain, which it mimics, kidney pain is usually felt in the upper back and will usually not improve by shifting positions or resting.
Common causes of kidney pain include kidney stones, kidney infection, dehydration, kidney trauma, polycystic kidney disease, and kidney cancer. The pain will often resolve when the underlying condition is treated. Over-the-counter or prescription painkillers, heat therapy, and ample hydration can help ease the discomfort and pain.
One of the reasons why people mistake kidney pain for back pain is that they don't actually know where their kidneys are. The kidneys are located higher up than many people imagine, housed on the lower portion of the rib cage and not in the middle of the back where "kidney punches" are thrown in movies and on television.
If you're uncertain whether your pain is stemming from your back or your kidneys, it is best to have it checked by a healthcare provider. If your primary care provider is unable to see you, there are telehealth nephrologists and urologists you can turn to, many of whom may be covered by insurance.
Kidney stones are the most common cause of kidney pain. Symptoms include a sharp, stabbing pain in the back or side that often starts suddenly and comes in waves. The pain will often move to the lower abdomen or groin as the body tries to rid itself of the hardened mineral deposit.
Kidney stones will often cause pain right before bedtime or just as you awaken because these are the times when you are less likely to urinate. During these times, the ureters that connect the kidneys to the bladder will constrict (narrow) to prevent urination. This, in turn, can intensify pain if you have kidney stones.
The symptoms of a kidney infection can overlap with a bladder infection but tend to be more severe. This is because the infection will have traveled upstream from the urethra and bladder to the ureters and kidneys. Symptoms include severe abdominal pain, nausea, vomiting, fever, chills, and pain on either one or both sides of the back.
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