Kidney stones are a common issue. Studies have shown that 14% of adults are affected by kidney stones at some point in their lives, and the number is increasing. Having a kidney stone can be very painful, and can lead to serious complications in some cases.
How does it feel to have a kidney stone? How do you know when you have one? What causes kidney stones to form?
Common Causes of Kidney Stones
Kidney stones form when minerals in the urine form crystals. There are a few different minerals that can form kidney stones, and the risk factors for getting kidney stones depend on the specific type.
- For calcium kidney stones, which are the most common type, the risk is increased by eating a diet high in oxalates (found in chocolate, spinach, beets, tea, and other foods), taking high doses of vitamin D, having intestinal bypass surgery, or taking certain medications.
- The risk of uric acid stones is increased by having diabetes or gout, being overweight, having chronic diarrhea, or eating a diet high in animal protein. These are the second most common type of kidney stones.
- Struvite kidney stones form in response to a urinary tract infection.
- Cystine stones form in people with a genetic predisposition to develop them.
After having one kidney stone, 50% of patients will go on to have another kidney stone within the next five years. Drinking alcohol doesn’t seem to increase the risk of kidney stones, although it can cause kidney damage. On the other hand, drinking plenty of water has been shown to decrease the risk of kidney stones.
How to Diagnose Kidney Stones
If your doctor suspects that you may have a kidney stone, there are a variety of tests that can be used. These include:
- Blood and urine tests to check the function of the kidney
- An ultrasound or CT scan to look for kidney stones within the urinary tract
If your kidney function has been affected, or if one or more kidney stones is too large for you to pass on your own, then you may need a procedure to help break up the kidney stone that it can pass. In many cases, ultrasound waves from outside the body are used to break up the stone, a procedure known as extracorporeal shock wave lithotripsy (ESWL). A scope can also be passed up the urethra, through the bladder, and into the ureter, allowing a doctor to use tools to break up the stone. In some cases, a surgical procedure to remove the stone from the kidney or ureter may be needed.
It can also be useful to determine what caused the kidney stone, which can be helpful in preventing another kidney stone from occurring. Tests that can be used for this include:
- Blood tests for calcium and uric acid
- A 24-hour urine collection, which looks at the levels of various substances in the urine
- Collection of the stone itself; this involves peeing through a fine mesh sieve to catch the stone when it passes, so it can be analyzed
Symptoms of Kidney Stones
People having a kidney stone often experience symptoms including:
- Pain in the back or flank, which may radiate to the abdomen or groin
- Burning or pain when urinating
- Strong feeling of the need to urinate
- Urinating frequently, often in small amounts
- Blood in the urine, which can cause the urine to look red, pink, or brown
- Nausea and vomiting
Symptoms of Kidney Stones for Males vs Females
The symptoms of a kidney stone are generally similar for men and women. This is because most of the symptoms occur while the stone is in the ureter, which is the tube that connects the kidney to the bladder. The length of the ureter is similar in both genders. The urethra is larger in diameter, so although men do have a longer urethra, this doesn’t cause them to experience more symptoms of kidney stones.
Men are more likely than women to experience kidney stones. However, this may be changing, as rates of kidney stones among females (both adolescents and adults) are rising.
Are kidney stones dangerous?
Most kidney stones are small enough to be passed by the body without causing lasting damage. They are often very painful, but usually won’t cause any serious health problems. However, some kidney stones are too large to be passed on their own. If these block the flow of urine through the ureter for too long, they may lead to kidney damage. This is one cause of chronic kidney disease; this causes few symptoms in its early stages, but can be very serious in its later stages. The only way to know whether you have chronic kidney disease is to get your kidney function tested. This can be completed at home or in a laboratory.
Kidney stones can also lead to infections in some cases. This requires treatment with antibiotics.
Can a kidney stone get stuck in the bladder?
In most cases, if a kidney stone makes it into the bladder, then it will be able to exit the bladder. This is because the ureter, the tube that carries urine from the kidney to the bladder, is smaller than the urethra, the tube that carries urine from the bladder out of the body. If a kidney stone is able to make it through the ureter and into the bladder, then it should be able to make it through the ureter and out of the body.
Can kidney stone pain come and go?
It’s very common for kidney stone pain to come and go. As the body tries to get rid of the kidney stone, waves of strong muscle contractions occur along the ureter. The pain can come and go with these waves.
Can kidney stones get bigger?
Kidney stones can get bigger over time. Once the mineral crystals of a kidney stone have started forming, additional minerals can deposit onto the surface of the kidney stone and make it bigger.
Can you feel a kidney stone moving?
As a kidney stone moves, the pain from the kidney stone can also move. Some of the pain comes from the kidney stone scraping against the inside of the ureter, and some from the intense muscular contractions the body uses to try and move it along.
Can you have a kidney stone without pain?
Many people do have kidney stones without pain. As long as the kidney stone is very small, it will easily pass through the ureter and out of the body, without causing any problems.
5 steps for preventing kidney stones. Harvard Medical School. https://www.health.harvard.edu/blog/5-steps-for-preventing-kidney-stones-201310046721. Accessed 22 June 2022.
Gillams K, Juliebo-Jones P, et al. Gender Differences in Kidney Stone Disease (KSD): Findings from a Systematic Review. FP Essent. 2021 Oct;509:33-38.
Kidney stones. Mayo Clinic. https://www.mayoclinic.org/diseases-conditions/kidney-stones/symptoms-causes/syc-20355755. Accessed 22 June 2022.
Kidney Stones. National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK). https://www.niddk.nih.gov/health-information/urologic-diseases/kidney-stones. Accessed 22 June 2022.