Kidney Stones

What Are Kidney Stones?

Kidney stones affect more than a million Americans each year. Twelve to 24 million Americans will develop stones in their lifetime and the incidence rate has increased dramatically over the last 20 years with approximately 350,000 new stone cases reported each year.

Kidney stones are created by a buildup of crystalline material like calcium and other salts, which collect in the kidney to form a stone. The stones can be as small as a grain of sand or as large as a golf ball. The size, shape, and location of the stone can cause many different symptons.

A person with kidney stones may experience severe pain or none at all. The amount of pain depends on how quickly the stone causes a blockage of urine flow. If a stone travels quickly from the kidney into the kidney tube (ureter), it can create an acute blockage of urine flow, causing the kidney to swell and resulting in intense pain.

Other signs of kidney stone disease include blood in the urine, recurring urine infections, severe nausea and vomiting. Most pain is located in the back, but can move toward the front of the lower abdomen or the flank. When a stone grows slowly within the kidney, little or no pain may be felt.

Kidney stone disease is two to three times higher in men than in women, and three to four times more frequent in whites than blacks, with middle-aged white men having a a 20% chance of getting kidney stones over their lifetime. The risk for women is only 5% to 10%. Once a person has a kidney stone, their chance of getting another one ranges from 65% to 90%. Interestingly, people living in the southeastern United States, also known as the stone belt, have the highest chance of getting kidney stones.

What Causes Kidney Stones?

Some causes of kidney stones can be attributed to conscious choices people make in their lifestyles, such as diet. The most likely cause of kidney stones is not drinking enough fluids. Eating too much calcium, protein, salt, or certain vitamins (Vitamin C, Vitamin D) can also lead to stone formation.

Patients can experience chemical problems with their metabolism, leaving high levels of calcium in the urine. High levels of other substances, such as oxalate (found in nuts, spinach, rhubarb and tea) and uric acid (a breakdown product of proten), and low levels of citrate or magnesium can also cause kidney stones.

Three conditions can cause non-calcium-containing stones:

• Too much uric acid or high acid levels in the urine can cause uric acid stone formation.
• Pure cystine stones, which are caused by a metabolism problem at birth, are determined by family history.
• The last cause of non-calcium kidney stones is a recurrent urinary tract infection. Infection stones are found in 10% to 15% of kidney stone patients. Women are three times more likely to get infection stones. Other people at risk are:
  • People who have repeated urine infections, and
  • Those who have had reconstruction of the urinary tract.

Certain medications may also cause "drug induced" kidney stones, such as ephedrine (most often found in cold medications and over-the-counter stimulants), guaifenesin (found in cough medicine), and indivar (used to treat HIV-positive patients).

Screening and Diagnosis

Metabolic testing for kidney stones is important for those patients who have formed multiple stones or those individuals who are at an increased risk for stone formation.

URORISK^® and STONERISK^® Diagnostic Profiles allow one to analyze the urine for various stone-forming risk factors. These diagnostic tests provide physicians tools to pinpoint underlying causes of kidney stones in their patients, resulting in efficient and cost-effective treatment. With the implementation of various diagnostic tests and corresponding medical care, stone disease can be prevented or controlled in 90% to 95% of patients.

Prevention and Treatment

Relieving pain is a priority after diagnosing kidney stones. When pain is under control, and x-rays do not show a significant blockage or infection, pain medication may be the only treatment necessary until the stones pass. In the past, open surgery was necessary for stone removal, but recently, treatment options have changed dramatically with non-invasive techniques such as shock wave lithotripsy (SWL), percutaneous nephtolithotomy (PNL), and ureteroscopy.

SWL is a popular non-invasive technique in which a lithotriptor sends sound waves into the body, crushing kidney stones into small pieces. Once the stones are small enough, they can come out with the urine through the urinary tract with little or no pain.

Fifteen to 20% of patients who have SWL may keep some stone fragments, which can cause a blockage of the urinary tract and require more treatment.

Percutaneous nephrolithotomy is a technique where a small hole is made in the patient's side and a telescope is put directly into the kidney. After identifying the stone with the telescope, an instrument, like a stone laser, passes through the telescope and breaks the stone into small pieces. The percutaneous technique is best for large or hard stones, or stones in the lower pole of the kidney. Large, hard or lower pole stones are not easy to break with SWL.

The final technique used to manage kidney stones is ureteroscopy. The main advantage of ureteroscopy is the reduction in pain and less need for hospitalization, with most ureteroscopic cases done as day surgery. In this procedure, a small telescope goes up through the bladder into the ureter. When the stone is located, small instruments are passed through the ureteroscope to break the stone into small pieces for removal.

The Benefits of Water

Patients can help prevent the future development of kidney stones. It is universally agreed that the single most important preventive measure is to drink lots of water. This is effective in diluting the concentration of chemicals which may crystallize into a stone. Patients with a propensity to form stones should drink at least 10 eight oz. glasses of water each day.

Prognosis

Kidney stone treatment has changed dramatically over the years, and continued medical therapy can prevent kidney stones from recurring.

With correct diagnosis and treatment of the underlying causes of kidney stone disease, 80% of patients can expect complete control over stone formation. Most stones can be removed with a minimum of pain and discomfort, and minimally invasive procedures have reduced patients' stay in the hospital and time lost from work.

This material is intended to provide basic information. All medical advice, diagnosis and treatment should be obtained from your physician.