What is a kidney stone?
A kidney stone is a hard mass that forms from crystals in the urine. In most people, natural chemicals in the urine stop stones from forming.
Are all kidney stones the same?
No. The most common types of kidney stones are made from calcium and oxalate. Individual treatment for kidney stones depends on the type of kidney stones that are formed.
Is there a diet I can follow to prevent me from having more kidney stones?
Sometimes following a special diet may be enough to prevent you from forming more kidney stones. Other times, medications, in addition to a special diet, may be needed. Please note that not all dietary recommendations benefit all types of stone formers.
What kind of diet will I have to follow?
You may be asked to make changes to the amount of salt (sodium), calcium, oxalate, protein, citrate, potassium and fluid in your diet. A registered dietitian can help you with making these changes.
My doctor told me to drink a lot of fluids. How much is "a lot"? Does it matter what kind of fluid I drink?
Staying well hydrated by drinking enough water is one of the best measures you can take to avoid kidney stones. To lessen your risk of forming a new stone, it is very important that you drink at least three quarts (12 cups) of fluid throughout the day. In hotter weather, you may need to drink more to make up for fluid loss from sweating. This will help keep your urine less concentrated. Less concentrated urine reduces the risk of stone formation. Most of the fluid you drink should be water. Try to drink a glass of water before bed and if you wake during the night to use the bathroom, drink another glass before going back to bed.
I had a calcium stone. What type of diet should I follow? Will I have to avoid high calcium foods?
Calcium is not the enemy. If you have high calcium in the urine then sodium reduction is helpful for stone prevention. Instead of reducing your calcium intake, focus on limiting the sodium in your diet and pair calcium-rich foods with oxalate-rich foods. Extra sodium causes you to lose more calcium in your urine, putting you at risk for developing another stone. Your doctor will probably advise you to limit sodium to 2,000 milligrams each day. There are many sources of "hidden" sodium such as canned or commercially processed foods as well as restaurant-prepared and fast foods. A dietitian help you understand food labels and make changes in the amount of sodium that you eat. If you do not have high calcium in the urine then for stone reduction you might be better off focusing on other dietary changes. Your doctor or registered dietitian can help determine if you need more or less calcium and help you plan a diet that is healthful.
I had an oxalate stone. What type of diet should I follow? Do I need to avoid foods high in oxalate?
Calcium oxalate kidney stones are the leading type of kidney stones. Oxalate is naturally found in many foods, including fruits and vegetables, nuts and seeds, grains, legumes, and even chocolate and tea. Some examples of foods that contain high levels of oxalate include: peanuts, rhubarb, spinach, beets, chocolate and sweet potatoes. The oxalate content of food can vary due to differences in such things as soil quality and state of ripeness. There may be variation in published data, too, as different methods may be used to determine the oxalate content of food.
Some research suggests that limiting high oxalate foods may help reduce your chance of forming another oxalate stone. However, many high oxalate foods are healthful so it is wise to not overly restrict your diet if not necessary. Most kidney stones are formed when oxalate binds to calcium while urine is produced by the kidneys. New research indicates that eating and drinking calcium and oxalate-rich foods together during a meal is a better approach than limiting oxalate entirely because oxalate and calcium are more likely to bind to one another in the stomach and intestines before the kidneys begin processing, making it less likely that kidney stones will form.
I had a uric acid stone. What does that mean? What type of diet should I follow?
Another common type of kidney stone is a uric acid stone. Red meat and shellfish have high concentrations of a natural chemical compound known as a purine. High purine intake leads to a higher production of uric acid which then accumulates as crystals in the joints, or as stones in the kidneys.
To prevent uric acid stones, cut down on high-purine foods such as red meat, organ meats, and shellfish, and follow a healthy diet that contains mostly vegetables and fruits, whole grains, and low fat dairy products. Limit sugar-sweetened foods and drinks, especially those that contain high fructose corn syrup. Limit alcohol because it can increase uric acid levels in the blood and avoid crash diets for the same reason. Eating less animal-based protein and eating more fruits and vegetables will help decrease urine acidity and this will help reduce the chance for stone formation.
You should also be sure to drink at least three quarts (12 cups) of water a day to help reduce the risk for stone formation. Making these healthy lifestyle changes can also help reduce your risk for developing gout because high uric acid is a leading risk factor for gout.
Is there anything else I can do with my diet to help prevent kidney stones?
Reducing the amount of animal protein may help. Sources of animal protein include beef, chicken, pork, fish and eggs. Most people need only four to six ounces of high protein foods and three servings of milk or cheese a day. Check with your doctor or dietitian to be sure your protein intake is enough, but not too much.
Chronic kidney stones are often treated with potassium citrate. Studies have shown that limeade, lemonade and other fruits and juices high in natural citrate may offer similar stone-preventing benefits. It is believed that citrate in the urine may prevent the calcium from binding with other constituents that lead to stones. Also, some evidence suggests that citrate may prevent crystals that are already present from binding with each other, thus preventing them from getting bigger. Please note that juices made from actual limes and lemons contain higher levels of citrate and beware of the sugar content in juices, because this can increase kidney stone risk.
Will it help/hurt me to take a vitamin or mineral supplement?
The B vitamins (which include thiamine, riboflavin, niacin, B6 and B12) have not been shown to be harmful to people with kidney stones. In fact, some studies have shown that B6 may actually help people with high urine oxalate. However, check with your doctor or dietitian for advice on the use of vitamin C, vitamin D, fish liver oils or mineral supplements containing calcium since some supplements can increase the chances of stone formation in some people.
History
A disease, followed by formation of stones in urinary system from dissolved urinary minerals. Reasons can be different - wrong eating habits, wrong medicines, genetic abnormalities, etc. Not a new disease; Stone has been found in Egyptian mummy at E1 Amrah, 4800 BC-1st eviedence of Urinary Stones.
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12th century BC; Sushruta performed perineal lithotomy.
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1879 ; Heinecke performed Pyelolithotomy
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1976 ; Fernstrom & Johansson described planned endoscopic surgery for the large kidney stone – PCNL.
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1980 ; Chausy – sound wave to break stones ESWL or Lithotripsy.
PREVELANCE
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1 in 10 persons develop Kidney stones in life time.
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5 – 10 % population is affected, 50 % of them have recurrence in next 5 t0 10 yrs.
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7-10 of every 1000 hospital admission.
What are the types of kidney stones?
Four major types of kidney stones can form:
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Calcium stones are the most common type of kidney stone and occur in two major forms: calcium oxalate and calcium phosphate. Calcium oxalate stones are more common. Calcium oxalate stone formation may be caused by high calcium and high oxalate excretion. Calcium phosphate stones are caused by the combination of high urine calcium and alkaline urine, meaning the urine has a high pH.
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Uric acid stones form when the urine is persistently acidic. A diet rich in purines—substances found in animal protein such as meats, fish, and shellfish—may increase uric acid in urine. If uric acid becomes concentrated in the urine, it can settle and form a stone by itself or along with calcium.
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Struvite stones result from kidney infections. Eliminating infected stones from the urinary tract and staying infection-free can prevent more struvite stones.
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Cystine stones result from a genetic disorder that causes cystine to leak through the kidneys and into the urine, forming crystals that tend to accumulate into stones.
Why is knowing which type of kidney stone a person has important?
The first step in preventing kidney stones is to understand what is causing the stones to form. This information helps the health care provider suggest diet changes to prevent future kidney stones. For example, limiting oxalate in the diet may help prevent calcium oxalate stones but will do nothing to prevent uric acid stones. Some dietary recommendations may apply to more than one type of stone. Most notably, drinking enough fluids helps prevent all kinds of kidney stones by keeping urine diluted and flushing away materials that might form stones.
How does a health care provider determine the type of kidney stone?
If a person can catch a kidney stone as it passes, it can be sent to a lab for analysis. Stones that are causing symptoms can be retrieved surgically or with a scope inserted through the urethra into the bladder or ureter, then sent to a lab for analysis.
Blood and urine can also be tested for unusual levels of chemicals such as calcium, oxalate, and sodium to help determine what type of kidney stone a person may have had.