Kidney Stones (Nephrolithiasis)
What is Kidney Stones (Nephrolithiasis)?
Kidney stones are hard deposits made from minerals and salts that form inside your kidneys. They develop when your urine contains more crystal-forming substances like calcium, oxalate, and uric acid than the fluid in your urine can dilute. These crystals stick together and grow into solid masses that can range from a grain of sand to a golf ball in size.
When stones stay in your kidneys, they often cause no problems. The trouble starts when they move into the tubes that carry urine from your kidneys to your bladder, called ureters. A stone traveling through this narrow passage can cause severe pain and block urine flow. This creates pressure that leads to swelling, pain, and sometimes blood in your urine.
Most kidney stones pass on their own within 48 hours if you drink plenty of fluids. Smaller stones often move through without you even knowing. Larger stones may need medical help to remove. Understanding your risk factors and getting tested can help you prevent stones from forming in the first place.
Symptoms
- Severe sharp pain in your side and back, below your ribs
- Pain that spreads to your lower abdomen and groin
- Pain that comes in waves and changes in intensity
- Pink, red, or brown urine indicating blood
- Cloudy or foul-smelling urine
- Burning sensation or pain when urinating
- Urgent need to urinate more often than usual
- Nausea and vomiting
- Fever and chills if infection is present
- Urinating only small amounts at a time
Some people have small stones that pass without any symptoms at all. Others may have stones sitting quietly in their kidneys for months or years before they start to move and cause pain.
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Causes and risk factors
Kidney stones form when your urine lacks enough fluid to dilute waste products. This allows minerals to crystallize and stick together. Dehydration is the single biggest risk factor. When you do not drink enough water, your urine becomes concentrated with stone-forming substances. Diet also plays a major role. Eating too much salt increases calcium in your urine. High amounts of animal protein, sugar, and oxalate-rich foods like spinach and nuts can raise your risk. Some people absorb too much calcium from food, which ends up in their urine instead of their bones.
Other risk factors include obesity, digestive diseases, certain surgeries like gastric bypass, and conditions that affect how your body processes calcium and other minerals. Family history matters too. If your parents or siblings had kidney stones, you face higher risk. Men develop stones more often than women. Having one stone greatly increases your chances of forming another within 5 to 7 years. Some medications and supplements, especially high-dose vitamin C and calcium supplements, may contribute to stone formation.
How it's diagnosed
Doctors diagnose kidney stones through your symptoms, physical exam, and testing. Blood in your urine is one of the classic signs that a stone is moving through your urinary tract. The mechanical trauma from a stone scraping the lining of your ureters causes bleeding that shows up in urine tests. Rite Aid's flagship testing panel includes urine blood screening to help catch this early warning sign.
Your doctor may also order imaging tests like CT scans or ultrasounds to see the size and location of stones. Blood tests check your kidney function and measure levels of stone-forming substances. A urine collection over 24 hours can show what types of crystals you are producing. If you pass a stone, your doctor may analyze it to determine what it is made of. This helps guide prevention strategies tailored to your specific type of stone.
Treatment options
- Drink 2 to 3 liters of water daily to help flush stones and prevent new ones
- Take pain relievers like ibuprofen or naproxen for discomfort as stones pass
- Use medications called alpha blockers to relax ureter muscles and help stones pass faster
- Reduce sodium intake to less than 2,300 milligrams per day
- Limit animal protein from meat, eggs, and seafood
- Eat calcium-rich foods with meals, which can reduce stone risk
- Avoid high-oxalate foods if you form calcium oxalate stones
- Get shock wave lithotripsy to break larger stones into smaller pieces
- Have ureteroscopy to remove stones with a small scope inserted through your urethra
- Consider surgery for very large stones that cannot pass
Concerned about Kidney Stones (Nephrolithiasis)? Get tested at Rite Aid.
- Simple blood draw at your nearest lab
- Results in days, not weeks
- Share results with your doctor
Frequently asked questions
Passing a kidney stone causes sharp, cramping pain in your back and side, usually below your ribs. The pain often moves to your lower abdomen and groin as the stone travels down. Many people describe it as waves of intense pain that come and go, making it hard to find a comfortable position.
Small stones under 4 millimeters usually pass within 1 to 2 weeks. Stones between 4 and 6 millimeters may take 2 to 3 weeks. Larger stones often need medical help to remove because they may not pass on their own. Drinking plenty of water can help speed up the process.
Yes, blood in your urine is one of the most common signs of kidney stones. The stone scrapes the lining of your urinary tract as it moves, causing bleeding. Sometimes the blood is visible and makes your urine pink or red. Other times it only shows up on a urine test.
The foods to avoid depend on your stone type. For calcium oxalate stones, limit spinach, rhubarb, nuts, and chocolate. For all stone types, reduce salt and animal protein. Contrary to old advice, you should not avoid calcium-rich foods like dairy. Eating calcium with meals actually helps prevent stones.
A regular blood test will not show the stones themselves, but it can reveal warning signs. Urine blood testing can detect bleeding caused by stones moving through your urinary tract. Blood tests can also check your kidney function and measure minerals like calcium that contribute to stone formation.
No, many kidney stones cause no symptoms when they stay in your kidneys. You only feel pain when a stone starts moving into the ureter. Small stones may pass into your bladder and out of your body without you noticing. Some people only discover they have stones during imaging tests done for other reasons.
Having one kidney stone raises your risk of forming another by about 50 percent within 5 to 7 years. Not drinking enough water, eating too much salt and animal protein, and being overweight all increase your risk. Family history, certain digestive conditions, and some medications also make you more likely to develop stones again.
Seek immediate care if you have severe pain that makes it impossible to sit still or find relief. Go to the ER if you have fever and chills along with pain, which signals infection. You should also get emergency help if you cannot keep down food or liquids, or if you see very little or no urine output.
Yes, staying well hydrated is the single most important step you can take to prevent kidney stones. Water dilutes the substances in your urine that form stones. Aim for 2 to 3 liters of water daily, or enough that your urine is light yellow or clear. This simple habit cuts your stone risk significantly.
Yes, kidney stones tend to run in families. If your parents or siblings had stones, you face 2 to 3 times higher risk of developing them yourself. This happens because stone-forming tendencies like how your body handles calcium can be passed down genetically. However, lifestyle choices still play a major role in whether you actually develop stones.