Kidney Stones

What is a kidney stone?
Causes of kidney stones
Types of kidney stones
Symptoms of kidney stones
Kidney stone treatment
Kidney stone prevention

What is a kidney stone?

Kidney stones are hard, stone-like masses, formed out of crystals found in the urine.

A stone may stay in the kidney or break loose and travel down the urinary tract. A small stone may pass all the way out of the body without causing too much pain. A larger stone may get stuck in a ureter, the bladder, or the urethra. A problem stone can block the flow of urine and cause great pain.

Researches have proved that kidney stones are no modern ailment; the remains of a 7,000-year-old mummy revealed that even the ancient Egyptians suffered from them.

Causes of kidney stones

Doctors still don’t know exactly what causes a kidney stone to form.

More than 90% of individuals with kidney stones have a chemical abnormality of blood or urine that contributes to the tendency to form the stones.

At one time, it was believed that certain foods caused people to develop kidney stones. Recent findings, however, suggest that foods may promote the formation of kidney stones in those who are susceptible, but it doesn’t seem that particular foods have any bearing on the formation of kidney stones in a person who is not susceptible. People who have a family history of kidney stones are more likely to develop them.

Not drinking enough water or other fluids may also contribute to forming stones. Inadequate fluid intake causes the kidneys to produce less urine, as well as urine that is highly concentrated. The smaller the daily volume of urine, the more likely it is that a person would form kidney stones.

The truth of the matter is that kidney stones may form for a variety of reasons: urinary tract infections, kidney disorders and certain metabolic disorders such as hyperparathyroidism have all been linked to the formation of kidney stones. Seventy percent of those who suffer from renal tubular acidosis, an unusual hereditary disease, develop kidney stones and the condition is most prominent in men, from ages 40-70. Women get stones less frequently than men, but occasionally they do occur, usually around the age of 50.

The most common kidney stones are calcium-based and related to a condition known as hypercalciuria, an inherited condition which causes stones when calcium is consumed in excess. Some other causes can include cystinuria and hyperoxaluria (two rare, inherited disorders of the metabolism), hyperuricosuria (a disorder of the uric acid metabolism), gout, excess intake of Vitamin D, blockage of the urinary tract (as in urethral stricture disease), and some diuretics. Even calcium-based antacids have been known to cause problems in some people.

Additionally, people with chronic inflammation of the bowel or those who have had an intestinal bypass surgery or ostomy operation may be at risk, as well as those who take a protease inhibitor known as endeavor, which is commonly used to treat HIV related infections.

One thing that is known: once a person gets a kidney stone, he is more likely to develop more of them in the future.

Types of kidney stones

1. Calcium phosphate stones are common and easily dissolve in urine acidified by vitamin C.

2. Calcium oxalate stones are also common but they do not dissolve in acid urine.

3. Magnesium ammonium phosphate (struvite) stones are much less common, often appearing after an infection. They dissolve in vitamin C acidified urine.

4. Uric acid stones result from a problem metabolizing purines (the chemical base of adenine, xanthine, theobromine [in chocolate] and uric acid). They may form in a condition such as gout.

5. Cystine stones result from a hereditary inability to reabsorb cystine. Most children's stones are this type, and these are rare.

Symptoms of kidney stones

While kidney stones don’t always cause symptoms, most of the time they do. The first symptom of a kidney stone is usually extreme pain. Kidney stones block the flow of urine and pain occurs when the stones try to shift and move. This causes a sharp, cramping pain, usually in the back and side in the area of the kidney or in the lower abdomen, and may be accompanied by a blood-tinted urine. Occasionally nausea and vomiting will accompany the pain and the patient may experience the need to urinate more. However, when they do go to urinate, they may experience a pressure and burning sensation. If there is a presence of fever or chill, though, this suggests that there may be an infection and one should seek a doctor immediately.

Kidney stone treatment

When a person cannot pass the stone through the urine, however, there are treatments available to remove or crush them, including:

• Inserting a small instrument through the urethra (the tube through which a person passes urine from the body) to “snare” the stone and remove it.

• Shock wave lithotripsy, whereby the stone is crushed. Once the stone is crushed, a person can pass the smaller pieces.

• Surgery.

Kidney stone prevention

• Drink more liquids. Drinking 8-10 glasses of liquid each day helps to keep the urine dilute, which reduces the concentration of stone forming minerals in the urine. At least half of the liquid should be water; the other liquids could be any beverages you like.

• Reduce the amount of salt you eat.

• Be sure your diet contains adequate amounts of calcium.

• Avoid those foods which can increase the amount of oxalate or uric acid in the urine: chocolate, anchovies, rhubarb, caviar, greens, herring, berries, scallops, peanuts, mussels, asparagus, organ meats (liver, kidneys, brains), tea, meat, extracts, broth, bouillon, consommé.

• Cranberry is known to help some people develop fewer kidney stones.