By: James Rogers, M.D.
Kidney stones form when certain materials, usually dissolved minerals such as calcium, build up over time and clump together to form small pebbles, or stones, in the kidney. The technical term for kidney stones is nephrolithiasis.
There are various types of kidney stones, based on the substances that form them. However, calcium stones are the most common. Calcium is a normal and important part of a healthy diet. Excess calcium goes to the kidneys where it is normally flushed from the body. Calcium stones form when the calcium stays in the kidney and combines with other substances, such as oxalate, phosphate or carbonate.
A second type of stone, known as a cystine stone, forms in people who have an inherited metabolic disorder known as cystinuria. This type of kidney stone runs in families. Struvite stones are formed by bacterial waste during a kidney or urinary tract infection. Finally uric acid stones occur with gout or during chemotherapy. Other substances can crystallize in the kidney to form stones, but these four are the most common.
A national survey, completed by the American Urological Association in 2010, showed 8.8 percent of respondents had at some time experienced a kidney stone. Prevalence was higher for men (10.6 percent) than for women (7.1 percent). These numbers show an increase from surveys done in the mid-1990s when overall prevalence was found to be 5.2 percent of respondents.
According to the National Institute of Health, kidney stones cause about 500,000 people to visit emergency rooms each year. About 2.5 millions people with less severe symptoms are treated for kidney stones annually.
Kidney stones can present a range of symptoms, making them difficult to diagnose. Pain can range from nonexistent to excruciating. Many times, the stones formed are very small. They pass from the kidney to the ureter and out of the body during normal urination without any symptoms at all.
When is stone gets stuck or is too large to pass easily, pain ensues.
When symptoms occur, they can include:
• Extreme, sharp pain radiating from the back or side, under the rib cage.
• Blood in the urine.
• Cloudy or odorous urine.
• Frequent urination.
• A burning feeling during urination.
• Nausea and vomiting.
• Fever and chills.
Symptoms of kidney stones can resemble other conditions or medical problems. Consult with your physician to get a specific and accurate diagnosis.
Certain characteristics put you at increased risk for kidney stones.
• Family or personal history – Some types of kidney stones tend to run in families. In addition if you’ve experienced a kidney stone, chance of recurrence is about 70 to 80 percent.
• Age – Kidney stones are most common in adults over age 40.
• Gender – Men are more likely to develop kidney stones than women.
• Diet – A diet high in protein, sodium and sugar may increase risk for some types of kidney stones.
• Ethnicity – Caucasians have the highest incidence of kidney stones, followed by Mexican Americans. African Americans have the lowest risk.
• Dehydration – Water flushes toxins from your body. Not drinking enough can increase your risk for kidney stones.
• Being obese – High body mass index and weight gain have been linked to an increased risk.
• Other medical conditions such as gout, high blood pressure, inflammatory bowel disease, urinary tract infections, hyperparathyroidism, kidney disease, chronic diarrhea, and certain cancers can increase risk.
• Medications such as those taken for AIDS, thyroid hormones, drugs to increase urination – called loop diuretics and certain chemotherapy drugs increase risk.
• Drink plenty of water throughout the day. Water helps flush away the substances the form kidney stones.
• Limit coffee, tea and caffeinated beverages.
• Consult with your physician about possible dietary modifications. This may include eating less oxalate-rich foods (if you have calcium oxalate stones). These include chocolate, sweet potatoes, nuts, beets, rhubarb, spinach, Swiss chard okra, tea and soy products. You may also want to follow a diet low in salt and animal protein. An analysis of a passed stone can prove helpful. Based on the make-up of the passed stone, dietary modifications may be possible to decrease the likelihood of the formation of future stones.
• Take any prescribed medications exactly as directed.
• Consult with your physician before taking any vitamin or mineral supplements.
• If you are overweight, consult with your physician about a weight loss plan.
Kidney stones require diagnosis by a doctor. If you experience symptoms of a kidney stone, make an appointment to see your primary care physician. If a stone is found, you can discuss treatment options together. Some of these include:
• Medications to decrease formation or cause stone breakdown.
• Medications to decrease pain.
• Drinking plenty of fluids.
• Extracorporeal shock-wave therapy to break up stones so they can exit the body.
• Removing larger stones with a tube inserted into the kidney through small surgical incision.
Today, most treatments for kidney stones are less invasive than in the past. Most often, when treated as soon as symptoms appear, no permanent damage is caused. If you experience the pain associated with possible kidney stones, see your physician to get an accurate diagnosis as soon as possible.
Dr. Rogers is a board certified family practice physician at Raiter Clinic in Cloquet.