DOCTORS CALL THEM RENAL CALCULI. To the general public, the small, hard crystals that sometimes occur in the kidneys or other parts of the urinary tract are known as kidney stones. Whatever you call them, they’re relatively common.
Kidney stones develop when various minerals and salts dissolved in urine become more concentrated, crystallize, and form solids, often as a result of inadequate hydration and/or other dietary factors. Varying in chemical makeup, the four main types of kidney stones are calcium oxalate (the most common), uric acid, struvite, and cystine (relatively rare).
Once formed, kidney stones may remain in the kidneys or travel to other parts of the urinary tract. The stones can range anywhere from the size of a grain of sand to, in rare cases, the approximate size of a golf ball. Very small stones can often be passed from the body naturally during urination, but larger stones or stones that become lodged at some point in the urinary tract require treatment.
According to the NKF, the most common symptoms of kidney stones include severe pain in the lower back, blood in the urine, nausea, vomiting, fever and chills, or urine that smells bad or looks cloudy. The pain commonly associated with kidney stones occurs when a stone obstructs the flow of urine and causes it to back up into the kidneys, not, as one might suspect, because the stone has a jagged or irregular shape.
If a stone doesn’t pass on its own with the aid of increased hydration, treatment may be necessary. The doctor will determine which treatment option is appropriate based on factors such as the location, size, and chemical composition of the stone. To list a few examples, medication may be used to facilitate easier passage of the stone, or high-energy sound waves (aka shock-wave lithotripsy) can be used to break up a stone into smaller fragments that are easier to pass in the urine. Another potential treatment option is ureteroscopy, which is performed under anesthesia and involves passing a small lighted tube, called a ureteroscope, into the obstructed ureter and using laser energy to break up the stone into smaller fragments to relieve the obstruction. In severe cases, surgery may be necessary to remove the stone.
With respect to prevention, because dehydration is the leading cause of kidney stones, one of the most important things people can do to avoid developing them is drink plenty of water. The easiest way to determine whether you’re drinking enough is to look at the color of your urine. Light-yellow or clear urine generally indicates adequate hydration, while darker urine is a sign that you need to increase your water intake.
In addition to staying properly hydrated, other measures you can take to limit your risk of developing kidney stones include:
• Limit your dietary intake of sodium. Excess sodium in the urine is known to prevent the reabsorption of calcium from the urine to the blood, which in turn leads to an increased level of calcium in the urine and, thus, a higher risk of developing stones.
• Get plenty of dietary calcium. Though calcium oxalate stones are the most common type, a calcium-rich diet actually lowers the likelihood of developing stones because it reduces the amount of oxalate absorbed by the body. Calcium supplements, on the other hand, have been linked to an increased risk of stones in some studies, so be sure to consult with your doctor before taking them.
• Limit your intake of animal protein, which decreases the pH of urine, an important factor in the formation of uric acid kidney stones.
• Increase your consumption of vegetables and fruits, especially citrus fruits such as oranges, grapefruit, lemons, and limes. The citric acid found in these fruits has been shown to protect against the formation of kidney stones.
• Avoid drinking colas or other beverages containing phosphoric acid, which is known to cause kidney stones.
• Avoid getting more than the recommended daily allowance of vitamin C. Excess levels of vitamin C may be associated with the formation of calcium oxalate stones.
In fact, the National Kidney Foundation reports that more than half a million Americans go to emergency rooms for kidney stone problems each year, and an estimated one in ten Americans will develop kidney stones at some point in their lives.
