What Every Man & Woman Should Know About Kidney Stones Ouch! Throughout my medical career, I have always been impressed with the severe amount of pain and suffering that a kidney stone can cause. In fact, it is one of the "great pains" in medicine and one that you are unlikely to forget. Kidney stones (calculi) are solid or semi-solid mineral-like substances occurring in the urinary tract. The urinary tract consists of the kidneys, ureters, bladder, and urethra. Urinary calculi may form anywhere along the urinary tract. The main problem occurs when the stones block the drainage of the kidney, resulting in urinary obstruction. It has been estimated that approximately 3% of the adult population in the United States will develop urinary calculi at least once in their lifetime. Urinary calculi are responsible for 10% of urological hospital admissions per year, accounting for approximately 400,000-plus patient hospitalizations. They also account for a significant number of visits to the hospital emergency departments and absenteeism from work each year. Upper urinary tract calculi are more common in adults than children and are seen more often in men than in women. Bladder stones are rare in women and children, but are common in men due to the greater incidence of lower urinary tract obstruction, e.g., prostate enlargement. Ten percent of males will experience kidney stones during their lifetime, which is almost three times the incidence in females. Caucasians are affected more commonly than other racial groups. Urinary calculi have been around for centuries. Stones were found in an Egyptian skeleton estimated to be over 7,000 years old. In the United States, archeologists have discovered urinary calculi in bony remains dating back to 1500 B.C. Many notable individuals have suffered with kidney stones, namely Louis Napoleon III (Emperor of France), Benjamin Franklin (American inventor), and Lyndon B. Johnson (American President). Kidney stones are more common in developed nations and do have regional variation in occurrence. In the United States individuals living in the so-called "sunbelts", e.g. southeastern and southwestern states are at higher risk for developing a stone than in other parts of the country. Although kidney stones have not been eradicated, we have learned a great deal about them. Because of this vast amount of knowledge and the revolutionary advancements in medical technology consistent with a proper evaluation and medical treatment, we are able to significantly decrease the recurrence of stone formation, decrease the pain and suffering associated with kidney stones, better preserve and protect the urinary tract, and -- where needed -- treat 95% of kidney stones without open surgery (surgery requiring a skin incision). Q. What causes kidney stones? Dr. Green: The exact causes of kidney stone formation are not completely known; however, most credible sources believe that stones are the result of mineral supersaturation and crystallization in the urine. Heredity, environment, age, sex, urinary infection, diet, and metabolic diseases are probably involved in stone formation. The primary known causes are: 1) inadequate urinary drainage, 2) dehydration and lack of sufficient fluid ingestion, 3) foreign bodies in the urinary tract, 4) diet with excess oxalates, calcium, and vitamin abnormalities, e.g., Vitamin A deficiencies, Vitamin D excess, 5) urinary infections, 6) metabolic diseases, e.g., hyperparathyroidism, cystinuria, gout, intestinal dysfunction, and 7) use of certain medications, e.g., diuretics, that increase levels of uric acid. Q. Are there racial differences in stone incidence and do stones run in families? Dr. Green: Yes, to both questions. Urinary calculi are relatively rare in American Indians, Africans and African-Americans, and native-born Israeli. Stone disease tends to run in families through a mechanism of partial penetrance due to a genetic defect. Q. How old does one have to be to get a kidney stone? Dr. Green: Urinary calculi can occur in patients of all ages; however, the peak incidence of urinary calculi occurs in the thirty- to fifty-year-old group. The typical stone patient is a Caucasian male between 20 and 60. Q. Can children have kidney stones? Dr. Green: Yes; however, urinary calculi in children are rare in the United States. In contrast, calculi are relatively common in children in Asia. The majority of stones in children are composed of uric acid. Q. Is there a "stone belt and season"? Dr. Green: In the United States the south is considered a stone belt due to the increased temperature and humidity and resultant dehydration state. Kidney stones occur all year; however, more patients present with stones during the summer months. Q. Are there different types of kidney stones? Dr. Green: Yes. The most common type of urinary stones are calcium, struvite (magnesium-ammonia phosphate), uric acid, xanthine, and cystine. Calcium stones are the most common. Q. What are the symptoms of kidney stones? Dr. Green: Symptoms of kidney stones may vary from none, in the case of "silent stones", to excruciating pain due to urinary obstruction from a stone. Most obstructing stones, depending upon cause, size, shape, and location, cause the following symptoms: - acute severe pain in the affected side (flank)
- nausea and vomiting
- hematuria (blood in the urine)
- possible infection
- possible fever
Q. What is a silent kidney stone?Dr. Green: A silent kidney stone is one that is not causing any significant urinary obstruction. It may spontaneously pass out of the urinary tract or remain in the kidney and grow, causing episodes of pain, hematuria, infection, and kidney damage. Q. How does one diagnose kidney stones? Dr. Green: X-ray is the chief method used to diagnose kidney stones. Ultrasound can also be used to detect stones and urinary obstruction. Q. What types of treatment(s) are available for kidney stones? Dr. Green: Treatment centers around medical and surgical; however, the size, location, degree of symptoms, and presence or absence of urinary infection and obstruction influence the treatment decision. Hospitalization is usually necessary for kidney obstruction and infection. A large number of kidney stones are small enough to pass spontaneously. Medical treatment is more successful in prevention of stones than in dissolving them after they have formed. Medical Treatment: - expectant (observation)
- medications
- adequate fluid intake
- maintaining proper urine pH
- diet
Q. If I get a kidney stone, what are my chances of passing it? Dr. Green: The size, configuration, and location affect the spontaneous passage of stones. However, stones less than 4 mm in diameter located in the lower ureter have a 90% change of passing. In contrast, stones greater than 6 mm in diameter have only a 20% chance of passing spontaneously. Surgical Treatment: - Extracorporeal shock wave lithotripsy (ESWL)
- PCN (percutaneous nephrolithotomy-lithotripsy)
- Endourology (endoscopic removal or manipulation)
- Open surgery
95% of stones can be removed without an incision employing the first three surgical treatment procedures. The technique, risk, benefits, success and potential complication vary, thus I would advise you to discuss these with your urologist. ESWL is one of the most popular techniques today. It works by using shock waves to fragment your stone into small pieces (sand-like) that pass freely through the urinary tract. During endourologic procedures the urologist looks directly into the ureter, and manipulates and retrieves the stone with small instruments. Both of these procedures are low risk, highly successful, and usually done as day surgery on an outpatient basis. Q. Do kidney stones recur? Dr. Green: Yes. Without proper treatment, after a stone has passed, or been removed surgically or fragmented with ESWL, the recurrence rate is approximately 50%. On the other hand, with proper surgical and medical treatment the recurrence rate can be reduced to 10% or less. However, in order to select proper medical management after treating urinary calculi it is imperative that the individual undergo a urinary stone medical evaluation. Q. What is a urinary stone medical evaluation? Dr. Green: The medical evaluation will consist of the following: - detailed medical history
- physical examination
- urine and blood test
- kidney x-ray/ultrasound
- metabolic stone risk profile
Q. Can kidney stones be dissolved? Dr. Green: The majority of kidney stones cannot be dissolved because they contain calcium; however, uric acid and cystine can be dissolved. Q. What can I do to prevent kidney stones? Dr. Green: You can minimize your risk by: - drinking 12 (8 oz.) glasses of water per day
- proper diet
- taking your stone prevention medication
- close follow-up by your doctor
Q. What is the future for kidney stones? Dr. Green: Research will continue in this country and abroad on developing less traumatic and more effective treatment methodology. However, our greatest impact on the prevention of pain, suffering, and kidney damage from urinary calculi will come when we are able to identify more accurately the at-risk population before they present with urinary stone disease, so that they can be treated early enough to prevent the formation of urinary calculi... preventive medicine. | 
