Trusted medical advice from the
American Academy of Family Physicians.

Kidney Stones

What are kidney stones?

Healthy kidneys remove waste products from your blood. These waste products leave your body in the urine your kidneys make. When the waste products don’t properly leave your kidneys, it can result in kidney stones.

A kidney stone is a hard, solid lump that forms in your kidney. The lump can be as small as a tiny pebble or it can be much bigger. It’s made from the waste products in your urine.

A kidney stone may stay in your kidney. It also may travel from your kidneys down the urinary tract. The urinary tract includes the ureters, bladder, and the urethra. If the stone is big enough, it can get stuck in your kidney or urinary tract. This can be very painful.

Symptoms of kidney stones

Kidney stones can cause a severe cramping pain in your lower back or side. The pain usually moves down toward your abdomen, groin, or genitals as the stone moves down the urinary tract. Other symptoms may include:

  • Nausea and vomiting
  • Cloudy or bloody urine
  • Fever
  • Feeling like you need to go to the bathroom more often than usual

What causes kidney stones?

There are four types of kidney stones. The calcium stone is the most common type. Calcium that isn’t used by your bones and muscles goes to your kidneys. Usually, the kidneys will get rid of the extra calcium through the urine. Calcium stones occur when some of the calcium remains in the kidneys and collects over time.

A struvite stone is more common in women. It usually forms after a chronic urinary tract infection. These stones are usually made of ammonia.

A uric acid stone forms when there is too much uric acid in the urine. You may be at risk for this type of stone if you eat a high-protein diet or if you’ve received chemotherapy.

A cystine stone isn’t very common. The disease that causes cystine stones to form runs in families and is called cystinuria.

How are kidney stones diagnosed?

Most of the time, you’ll be able to pass your kidney stone without the help of a doctor. If your kidney stone gets stuck in the urinary tract, you may need your doctor’s help.

To determine if you have a kidney stone, your doctor will ask you about your symptoms. He or she will take a sample of your urine. Your doctor will order images of your kidneys and urinary tract.

Can kidney stones be prevented or avoided?

Most people who have kidney stones have a 50% chance of developing another kidney stone within 10 years. But there are things you can do to lower your risk:

  • Drink at least 2 liters of fluids (water is best) per day. Your doctor may have you measure your urine output to be sure you’re drinking the right amount of fluids.
  • Don’t eat more than 1,500 mg of salt per day (about 1 teaspoon). This includes salt in pre-packaged food. Check nutrition labels to see how much salt (sodium) is in your food.
  • Try not to eat more than 2 servings of meat per day. Each serving should be no more than 6 to 8 ounces.

There are several risk factors for kidney stones, including:

  • Not drinking enough fluids, especially water
  • Family history of kidney stones
  • Eating a diet high in protein and sodium but low in fiber
  • Being a man
  • Being between 20 and 70 years of age
  • Being bedridden or immobile for a long period of time
  • Taking certain medicines
  • Being overweight

Kidney stones treatment

If the stone is small enough, you might be able to pass it in your urine. Your doctor can give you medicine to help with the pain. Your doctor may also suggest you filter your urine and submit any stones for further testing or analysis.

If the stone is too big or is causing an infection, your doctor may intervene. They may suggest a procedure or refer you to a urologist. They may use a special machine that uses shock waves to break up the stone into smaller pieces. This is called extracorporeal shock wave lithotripsy, or SSWL.

A urologist (urinary tract surgical specialist) can put a very thin instrument through your urethra and into your bladder and ureters to find the stone. He or she can then pull it out or break it into smaller pieces. If a doctor does this, you will be given medicine to numb the area first.

Surgery is also an option and is sometimes the only way to get rid of a kidney stone.

Living with kidney stones

If you have had more than one kidney stone, your doctor might send you to a specialist to find the exact cause of your stones. Some people need medicine to keep from getting another kidney stone.

Questions to ask your doctor

  • What treatment is best for me?
  • What pain medicine should I take?
  • Will I need surgery?
  • Will the stone pass by itself?
  • Should I change my diet?
  • Are there any other lifestyle changes I should make?
  • Will I get more kidney stones in the future?
  • Are my children at higher risk of kidney stones?
  • When should I call my doctor?
  • If my pain is bad enough, should I go to the emergency room?
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