Key takeaways:
Kidney stones are small collections of sediment that form in the kidney. They can cause pain when they leave the kidney and start to travel the urinary tract.
Kidney stone pain can feel severe, and it tends to come and go without warning. The pain is located in the side (flank), back, or abdomen. It also frequently shoots into the groin.
People often go to the ER seeking relief from the pain. But any healthcare provider can diagnose a kidney stone with urine and imaging studies.
Kidney stones are tiny, rock-like substances that form in the kidney and sometimes travel down the urinary tract. They are common, affecting 11% of men and 7% of women in the U.S.
Despite their small size, kidney stones are notorious for causing episodes of sharp, severe pain. This pain can feel as alarming as it is unbearable. And for someone experiencing their first kidney stone, it can be difficult to tell if your symptoms are caused by a kidney stone or some other condition.
Below, we’ll provide some helpful information to help you figure out if your pain is caused by a kidney stone and explain when it’s time to see a healthcare provider.
Kidney stones are collections of sediment that form in the kidney. Some remain in the kidney indefinitely, and, here, they don’t cause any pain, because they have plenty of room. But if they leave the kidney and start to travel the rest of the urinary tract, this is when they start to cause some problems. The kidney stone is often wider than the urinary tract, which causes pain.
The urinary tract carries urine from the kidney to the bladder and then outside the body. This is also the path that kidney stones follow. And to understand kidney stones, it helps to understand the anatomy of the urinary tract, which is made up of:
Two kidneys, which filter our blood and make urine. They also filter substances that can solidify into kidney stones.
Two ureters, which are narrow tubes that connect each kidney to the bladder. Kidney stone pain occurs when the stone begins to travel down the ureter or blocks the flow of urine.
The bladder stores urine until we are ready to urinate. Kidney stones in the bladder will not typically cause pain because they have plenty of space to just float around.
The urethra is another narrow tube that carries urine — and kidney stones — from the bladder to the outside world.
Kidney stones form when there is too much of a substance in the urine, causing it to form solid crystals rather than staying dissolved. Different dissolved substances can solidify, forming different types of kidney stones.
Kidney stones can vary in size from almost microscopic to the size of a peanut or even larger. But the size of a kidney stone does not necessarily correlate to pain or severity of symptoms. In fact, some smaller stones may cause more pain because they are just the right size or shape to stretch out or block the ureter and cause problems.
The main symptom that occurs when a kidney stone moves through or blocks the ureter is intense pain — also called “renal colic.” The pain is quite unique to kidney stones, and so it can help to distinguish kidney stones from another condition, as not much else feels like it.
Here are some of the common characteristics of kidney stone pain:
It is usually located in your mid to lower back, side (flank), or lower abdomen.
The pain tends to start and stop abruptly. It might feel like it comes (and goes) out of nowhere.
Oftentimes, people feel like the pain shoots down into their groin.
One unique characteristic of kidney stone pain is that many people feel they want to get up and move around while it’s occurring. This is not the case for most other types of back or abdominal pain.
The pain tends to bring on a clammy feeling, or an intense feeling of nausea (and sometimes vomiting) when it is most severe.
Kidney stones can also cause other symptoms besides pain. You may notice dark, cloudy, or bloody urine. You might have a sensation of urinary hesitancy or urgency. Kidney stones can also lead to urinary tract infections, which can be associated with a whole different set of symptoms. We will talk more about this below.
Many people who are experiencing kidney stone symptoms don’t wait long to see a healthcare provider — mainly to get some much needed relief from the pain. When you see a provider, the way you describe your pain will give them a pretty good clue if it is a kidney stone or something else. They may also check tests to diagnose the stone or rule out other conditions.
These tests include:
Urine tests to check for blood in the urine or signs of infection.
Imaging studies that may show a kidney stone in the urinary tract. These may include an ultrasound, X-ray, or a CT scan. A CT scan is the best test to find most kidney stones. But sometimes they can be seen with an ultrasound or X-ray. And these tests have the advantage of less radiation exposure.
Blood tests for calcium, uric acid, and phosphorus levels. Abnormally high levels of these substances in the blood can help point to the cause of the stone. And these tests can be a clue to what the stone is made of, which is important to prevent more stones in the future.
Kidney stones can also be diagnosed incidentally. Like when someone gets a CT scan for some other reason, and it shows stones sitting inside the kidney. Here, they tend not to cause any pain or problems.
Most people with kidney stone pain see a provider simply for help for relief from the pain. But there are other reasons you should not delay medical care, even if the pain is manageable at home:
You are having pain in your side, back, or abdomen that is constant or worsening.
You have noticeable, bright-red blood in your urine.
You are unable to urinate.
You have a fever or chills, especially when combined with the above symptoms.
Some of the above symptoms may be due to a developing urinary tract infection, which can be a serious complication of kidney stones. This occurs when the stone is preventing the infected urine from leaving the body. People with this complication can get sick very quickly and should not delay care. They usually need antibiotics, and possibly even a procedure to remove the kidney stone.
But most kidney stones are not coupled with infection. And that means most kidney stones can be treated with pain medication, good hydration, and time to allow the stone to pass through the urinary tract.
Kidney stones can form when substances solidify in the kidney. They aren’t a problem until they decide to leave the kidney and travel down the very narrow ureters.
Symptoms of a kidney stone can include significant pain in your back, side, or abdomen. This is often accompanied by bloody or cloudy urine, nausea, and even vomiting. A healthcare provider can help alleviate these uncomfortable symptoms and determine if you have a kidney stone by checking blood and imaging studies. The dual treatment often involves pain control and time to allow the stone to pass.
American Kidney Fund. (2021). Kidney stone causes, symptoms, treatments, & prevention.
Dhar, M., et al. (2009). Imaging in diagnosis, treatment, and follow-up of stone patients. Advances in Chronic Kidney Disease.
National Institute of Diabetes and Digestive and Kidney Diseases. (2017). Diagnosis of kidney stones.
National Institute of Diabetes and Digestive and Kidney Diseases. (2020). The urinary tract & how it works.
Portis, A. J., et al. (2001). Diagnosis and initial management of kidney stones. American Family Physician.
Sasmaz, M. İ., et al. (2019). The relationship between the severity of pain and stone size, hydronephrosis and laboratory parameters in renal colic attack. The American Journal of Emergency Medicine.
Tundo, G., et al. (2021). Beyond prevalence: Annual cumulative incidence of kidney stones in the United States. The Journal of Urology.