About Kidney Stones
Each year, more than half a million people go to emergency rooms for kidney stone problems. lt is thought that one in ten people will have a kidney stone at some time in their lives.
The number of people in the United States with kidney stones has been increasing over the past 30 years. In the late 1970s, less than 4% of the population had had kidney stones; by the early 1990s, more than 5%. The rates are continuing to increase.
The peak age for stones is between 20 years and 50 years. White Americans are more prone to develop kidney stones than African Americans, and men are much more likely to develop stones than women. Other diseases like high blood pressure, diabetes, obesity, osteoporosis, chronic diarrhea, or kidney cysts might increase the risk of stones. Diabetes increases the risk of developing kidney stones, especially in younger women. Only about 25% of kidney stones occur in people with a family history of stones. Doctors say they're seeing increasing numbers of children with kidney stones. After bariatric (weight loss) surgery, in which the digestive tract is altered, kidney stones are more common. Levels of oxylate are much higher after this surgery.
View and download the Kidney Stone Infographic.
Signs and Symptoms
Some kidney stones are as small as a grain of sand. Others are as large as a pebble. A few are as large as a golf ball! As a general rule, the larger the stone, the more noticeable are the symptoms.
The symptoms could be one or more of the following:
- severe pain on either side of your lower back
- more vague pain or stomach ache that doesn't go away
- blood in the urine
- nausea or vomiting
- fever and chills
- urine that smells bad or looks cloudy
The treatment for kidney stones is similar in children and adults. You may be asked to drink a lot of water. Doctors try to let the stone pass without surgery. But if it is too large, or if it blocks the flow of urine, or if there is a sign of infection, it is removed with surgery.
Shock-wave lithotripsy is a noninvasive procedure that uses high-energy sound waves to blast the stones into fragments that are then more easily passed out in the urine. In ureteroscopy, an endoscope is inserted through the ureter to retrieve or obliterate the stone. Rarely, for very large or complicated stones, doctors will use percutaneous nephrolithotomy/nephrolithotripsy. Ask your doctor to evaluate which, if any, treatment might be right for you.
Drinking enough fluid will help keep your urine less concentrated with waste products. Darker urine is more concentrated, so your urine should appear very light yellow to clear if you are well hydrated. Most of the fluid you drink should be water. Most people should drink more than 12 glasses of water a day. Water is better than soda, sports drinks or coffee/tea. lf you exercise or if it is hot outside, you should drink more. Sugar and high-fructose corn syrup should be limited to small quantities.
You can reduce excess salt in your diet. What foods are high in salt? Everyone thinks of salty potato chips and French fries. Those should be rarely eaten. There are other products that are salty: sandwich meats, canned soups, packaged meals, and even sports drinks.
You want to try to get to a normal weight if you are overweight. But, high-protein weight loss diets can add to the stone risk. Protein is found in beef, chicken, pork, fish, milk, and eggs. You need protein (50 grams a day), but it needs to be part of a balanced diet.
Don't be confused about having a "calcium" stone. Dairy products have calcium, but they actually help prevent stones, because calcium binds with oxalate before it gets into the kidneys. People with the lowest dietary calcium intake have an increased risk of kidney stones. A stone can form from salt, the waste products of protein, and potassium. The most common type of kidney stone is a calcium oxalate stone. Most kidney stones are formed when oxalate (a by product of certain foods like rhubarb, spinach, beets, peanuts, chocolate, and sweet potatoes) binds to calcium as urine is being made by the kidneys. Both oxalate and calcium are increased when the body doesn't have enough fluids and also has too much salt.
Some herbal substances are promoted as helping prevent stones. You should know that there is insufficient published medical evidence to support the use of any herb or supplement in preventing stones.
See your doctor and/or a registered dietitian about making diet changes if you have had a stone or think you could be at increased risk for getting a kidney stone. To guide you, they need to know your medical history and the food you eat. Here are some questions you might ask:
What food may cause a kidney stone?
Should l take vitamin and mineral supplements?
What beverages are good choices for me?
For more information on kidney stones, visit the National Kidney Foundation's Kidney Stones page.