Kidney stones usually comprised of a compound called calcium oxalate, are the result of an accumulation of dissolved minerals on the inner lining of the kidneys. These deposits can grow to the size of a golf ball while maintaining a sharp, crystalline structure.
The kidney stones may be small and pass unnoticed out of the urinary tract, but they may also cause extreme pain upon exiting.
Kidney stones that remain inside the body can lead to many conditions, including severe pain and ureter (the tube connecting the kidney and bladder) blockage that obstructs the path urine uses to leave the body.
Scientists at the Mayo Clinic, Rochester, USA, say that people with kidney stones are at a significantly higher risk of developing chronic kidney disease.
Causes of kidney stones
Kidney stones can vary in size. Some have been known to become as big as golf balls.
The leading cause of kidney stones is a lack of water. Stones commonly have been found in those that drink less than the recommended eight to ten glasses of water a day. When there is not enough water to dilute the uric acid (component of urine), the pH level within the kidneys drops and becomes more acidic. An excessively acidic environment in the kidneys is conducive to the formation of kidney stones.
Medical conditions such as Crohn's disease, urinary tract infections, renal tubular acidosis, hyperparathyroidism, medullary sponge kidney, and Dent's disease have been known to lead to kidney stones. It also has been suggested that water fluoridation - the addition of fluoride to drinking water - is responsible for some cases of kidney stones.
Vitamin D and Calcium supplements linked to kidney stone risk
A study carried out by scientists at Creighton University Medical Center suggested that calcium and vitamin D supplements could increase the risk of developing kidney stones because they raise levels of calcium in the blood and urine.
Head researcher, J. Christopher Gallagher, M.D., explained that perhaps using vitamin D and calcium supplements is not as benign as people had thought. He advised people not to exceed the guidelines for these supplements of 800 international units of vitamin D, and 800-1,200 milligrams of calcium per day (according to the Institute of Medicine).
When asked which of the two supplements might be raising kidney stone risk, Dr. Gallagher said:
"It is not clear whether it is the extra calcium, the vitamin D or both together that cause these problems.
However, it is possible that long-term use of supplements causes hypercalciuria and hypercalcemia, and this can contribute to kidney stones. For these reasons, it is important to monitor blood and urine calcium levels in people who take these supplements on a long-term basis. This is rarely done in clinical practice."
Who gets kidney stones?
Kidney stones are twice as common among males as females. Most people who experience kidney stones do so between the ages of 30 and 50. A family history of kidney stones also increases one's chances of developing them at some point in life. Similarly, a previous kidney stone occurrence increases the risk that a person will develop subsequent stones in the future if preventative action is not taken.
Certain medications can increase the risks of developing kidney stones. Scientists found that opiramate (Topamax), a drug commonly prescribed to treat seizures and migraine headaches, can increase the propensity of calcium phosphate kidney stone.
Additional risk factors for kidney stones include diets that are high in protein and sodium but low in calcium, a sedentary lifestyle, obesity, high blood pressure, and conditions that affect how calcium is absorbed in the body such as gastric bypass surgery, inflammatory bowel disease, and chronic diarrhea.
A study indicated that kidney stones among children are on the rise.
Symptoms of kidney stones
A kidney stone usually remains symptomless until it moves into the ureter. When symptoms of kidney stones become apparent, they commonly include:
- Severe pain in the groin and/or side
- Blood in urine
- Vomiting and nausea
- White blood cells or pus in the urine
- Reduced amount of excreted urine excreted
- Burning sensation during urination
- Persistent urge to urinate
- Fever and chills if there is an infection
On the next page we look at how kidney stones can be diagnosed, plus treatment methods and thoughts on how to prevent kidney stones occurring.