Kidney Stones - Symptoms and Diagnosis

Symptoms

Very small kidney stones may pass out of the body in the urine without causing symptoms. Larger stones may become trapped in the narrow ureter, causing severe pain in the back or side, nausea and vomiting, or blood in the urine. If there is blood in your urine, the urine may look pink, red or brown. If the location of pain shifts downward, closer to the groin, this usually indicates that the stone has traveled downward in the ureter and is now closer to the bladder. As the stone approaches the bladder, you may feel a stronger urge to urinate or a burning sensation when urinating. When stones pass out of your body in your urine, you may see the stones exit.

Diagnosis

Your doctor will ask you about your symptoms and about any change in the color of your urine. He or she will ask about your family history of kidney stones and whether you have had gout.

A sample of your urine can be tested for blood. Because certain bacterial infections in the urine can lead to kidney stones, your urine may also be tested for infection.

Your doctor can use X-rays, computed tomography (CT) scans or ultrasound to look for a kidney stone and see if it is trapped. An X-ray can also show kidney stones in many cases.

If you are able to collect a stone that you passed from your urine, your doctor can send the stone to a laboratory for chemical analysis. So that you can collect your stone more easily, your doctor may provide you with a strainer into which you can urinate.

Your blood and a volume of urine that you collect at home over 24 hours can be tested to see if you have an excess in certain mineral levels relative to others. This can help your doctor to identify a specific cause of the stone, and may allow your doctor to advise you about ways to prevent a recurrence.

Kidney Stones Breakthrough

How To Prevent Kidney Stones

You can help prevent kidney stone formation by avoiding high levels of calcium and uric acid in urine. Here's how:

1) Drink plenty of fluids. This will help prevent dehydration and flush substances that form stones out of the kidneys and urinary tract. Drink 8 to 12 cups (64 to 96 ounces) a day. Drinking alcohol only affects stone formation by causing dehydration since it has a diuretic effect. Alcohol can be enjoyed in moderation if the drinker is careful to maintain hydration. The amount of oxalates in black tea is small. So, tea can be enjoyed in moderation also. Studies have shown that coffee may help reduce the incidence of stone formation, despite having caffeine, which is a natural diuretic and may increase urinary calcium excretion.

2) Eat 1,000 to 1,200 milligrams of calcium a day. This is important because in the gut, calcium binds oxalate, a bitter component found in some plants. This helps decrease the amount of oxalate that is absorbed. When less oxalate is absorbed, less is excreted in the urine and fewer calcium oxalate stones can form. Oxalate promotes stone formation in the urine about 15 times more frequently than calcium. Some good sources of calcium include low-fat or fat-free dairy products, such as milk, yogurt, cottage cheese and cheese. Other good sources of calcium include calcium-fortified orange juice, calcium-fortified soy milk, tofu, broccoli, sardines, collard greens, almonds and black beans.

3) Limit oxalate intake to 40 to 50 milligrams a day. It's not clear how much oxalate from food the body absorbs, or even how accurately we can measure oxalate levels in food. Nevertheless, avoid the following foods, some of which have more than 10 milligrams of oxalates per 3.5 ounce serving: Most types of beans, nuts, dark green leafy vegetables, berries, chocolate, rhubarb stalks, most soy products, star fruit and black pepper (over 1 teaspoon). It's especially important that individuals whose urine contains a high level of urinary oxalate avoid these foods. For more information see the Harvard School of Public Health's resources on low-oxalate foods.

4) Limit animal protein (dairy products, eggs, meats, poultry and fish) intake since it can increase the acidity of the blood. The body metabolizes animal protein by pulling calcium from the bones to buffer the acidity. The excess calcium eventually ends up in the urine at a higher concentration, which can make it easier for oxalate stones to form.

Kidney stones

Kidney stones are hard, crystal-like concentrations of minerals in the urine. Stones that form in the kidney are called nephrolithiasis; stones that form in the urinary tract are called urolithiasis. The most common type of kidney stone is the calcium oxalate stone. It makes up about 80% of all kidney stones. Five percent of people will develop kidney stones at some point in their lives. Men have kidney stones about four times more often than females.

What Causes Kidney Stones?
Kidney stones form when a person doesn't drink enough fluid to dilute the urine. This increases the chance that chemicals or excess minerals will combine to form stones. A calcium oxalte stone forms when there is an excess of calcium in the urine.
The risk of developing kidney stones goes up after age 40 and increases as you get older. Individuals who have had more than one kidney stone and those with a family history of kidney stones are more likely to develop kidney stones. More than 50% of people with an inherited condition called hypercalciuria form kidney stones. Their bodies absorb extra calcium in food, which results in a high calcium level in the urine.

As a stone passes through the urinary tract, it can cause severe pain in the abdomen and groin. The pain can lead to nausea and vomiting. If the stone damages the lining of the urinary tract, there may be blood in the urine (hematuria).

Treating Kidney Stones

The most important treatment for passing stones is drinking enough fluid. This will help flush the stone through the urinary tract. The goal is to drink 8 to 12 cups (64 to 96 ounces total) each day. Pain medication, if needed, can help while trying to pass a kidney stone. Medications, such as nifedipine, may help speed up the process of passing the stone. If the stone is too large to pass through the urinary tract, your doctor may recommend treatment with shock waves (lithotripsy) to break it up or a minor surgical procedure to either break it up or remove it.