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Renal stones, more commonly known as kidney stones, are crystallized formations of waste products in urine. Stones can go unnoticed, passing without difficulty through the bladder and urethra. Larger renal stones may cause blockage of the urine by blocking the ureter, the central tube through which urine passes from the kidneys. Such blockage causes severe pain, and while most stones pass on their own, medical treatment is frequently sought to effectively break down or eliminate renal stones.
The four most common types of renal stones are cystine, struvite, uric acid, and calcium. Of these, calcium formations are the most common, accounting for about 80% of all cases of kidney stones. While the kidneys generally remove calcium from the body, calcium in excess can combine with other chemicals to form renal stones. A lack of the proper amount of citrate, sometimes caused by renal insufficiency, may further induce the creation of these stones.
Cystine stones are the least common of renal stones. A congenital condition, cystinuria, creates high levels of cystine, an amino acid, in urine. Because cystine does not break down easily in urine, stone formation is frequent in cystinuria sufferers.
Unfortunately, cystinuria requires consistent treatment because it is not curable. Treatment normally involves increasing fluids and taking several oral medications like bicarbonate and penicillin to reduce the number of renal stones formed. Larger stones may require surgical removal.
Urinary tract or bladder infections can cause struvite renal stones. Struvite formations are more common in women because women are more prone to bladder infections. These stones often become quite large and are jagged in appearance. Treatment can include increased fluids and antibiotics to address the urinary tract infection.
Uric acid renal stones, more common in men, are caused when excessive levels of digestive acid are processed through the kidneys. The kidneys may form stones around these acids. Development of these kidney stones may be an inherited condition.
Kidney stones are generally diagnosed when a patient seeks treatment for intense pain in the kidneys or bladder. Such pain may be felt in the lower back on either side of the spine. Pain may be accompanied by nausea, difficulty urinating, or blood in the urine. It's important to see a medical professional as soon as possible, as with some renal stones the pain does not improve and the stone cannot pass without treatment. Diagnosis is generally made through urine analysis, x-rays, and occasionally ultrasounds.
Treatment for most renal stones involves increased fluid intake, pain medication as needed, and anti-inflammatory medications like ibuprofen to decrease swelling and help the stone to pass. Most kidney stones pass within 3-4 days, though it is not unusual for stone passage to take several weeks. Physicians may undertake more aggressive treatment if the stone does not pass, if pain is constant, or if the presence of stones is worsening kidney or bladder infections.
Shock wave treatment uses electrical shocks to hit and break up the stone, creating easier passage. Patients undergoing this outpatient procedure may resume activities within a few days. A larger stone in the kidney may require nephrolithotomy. Through an incision in the back, the stones are removed completely. When a stone is caught in the mid or lower ureter, a catheter called an ureteroscope is passed into the urethra and bladder to break up the stone.
Except in congenital cases, most people can easily prevent the formation of kidney stones by a few simple dietary changes. Staying well hydrated is essential. Increasing magnesium and citrate, found in most juices, can also limit the formation of renal stones. High amounts of Vitamin C and calcium can increase risk. However, since calcium is so important in the prevention of osteoporosis, reducing calcium intake or supplements should only be done under a doctor's care. Alcohol and most rich or high calorie foods, like ice cream, produce uric acid, so limiting these foods to the occasional treat is sensible.