<br />Kidney Stones<br />Composition, Diagnosis and Prevention<br />Prof. Dr. Hadi Yasir Abbood<br />Health and Medical Techniques College<br />Almustaqbal University <br /><br />The stones are hard objects, made up of millions of tiny crystals. Most kidney stones form on the interior surface of the kidney, where urine leaves the kidney tissue and enters the urinary collecting system. Kidney stones can be small, like a tiny pebble or grain of sand, but are often much larger.<br /><br />The job of the kidneys is to maintain the body's balance of water, minerals and salts. Urine is the product of this filtering process. Under certain conditions, substances normally dissolved in urine, such as calcium, oxalate and phosphate, become too concentrated and can separate out as crystals. A kidney stone develops when these crystals attach to one another, accumulating into a small mass, or stone.<br /><br />Kidney stones come in a variety of mineral types:<br /><br /><br />Calcium stones: Most kidney stones are composed of calcium and oxalate. Many people who form calcium containing stones have too much calcium in their urine, a condition known as hypercalciuria There are several reasons why hypercalciuria may occur. Some people absorb too much calcium from their intestines. Others absorb too much calcium from their bones. Still others have kidneys that do not correctly regulate the amount of calcium they release into their urine. There are some people who form calcium oxalate stones as a result of too much oxalate in the urine, a condition known as hypercalciuria In some cases, too much oxalate in the urine is a result of inflammatory bowel disease, such as Crohn's disease or ulcerative colitis, or other times it may be a consequence of prior intestinal surgery. Calcium phosphate stones, another kind of calcium stone, are much less common than calcium oxalate stones. For some people, calcium phosphate stones form as a result of a medical condition known as renal tubular acidosis.<br /><br />Struvite stones: Some patients form stones that are composed of a mixture of magnesium, ammonium, phosphate and calcium carbonate, which is known as struvite. These stones form as a result of infection with certain types of bacteria that can produce ammonia. Ammonia acts to raise the pH of urine, which makes it alkaline and promotes the formation of struvite.<br /><br />Uric acid stones: Uric acid is produced when the body metabolizes protein. When the pH of urine drops below 5.5, urine becomes saturated with uric acid crystals, a condition known as hypercalciuria. When there is too much uric acid in the urine, stones can form. Uric acid stones are more common in people who consume large amounts of protein,<br /> <br />such as that found in red meat or poultry. People with gout can also form uric acid stones.<br /><br /><br />Cystine stones: Cystine stones are rare, and they form only in persons with an inherited metabolic disorder that causes high levels of cystine in the urine, a condition known as cystinuria.<br /><br />How are kidney stones diagnosed?<br />Most people are diagnosed with kidney stones after the thunderclap onset of excruciating and unforgettable pain. This severe pain occurs when the kidney stone breaks loose from the place that it formed, the renal papilla, and falls into the urinary collecting system. When this happens, the stone can block the drainage of urine from the kidney, a condition known as renal colic. The pain may begin in the lower back and may move to the side or the groin. Other symptoms may include blood in the urine (hematuria), frequent or persistent urinary tract infections, urinary urgency or frequency and nausea or vomiting.<br /><br />When your doctor evaluates you for a kidney stone, the first step will be a complete history and physical examination. Important information regarding current symptoms, previous stone events, medical illnesses and conditions, medications, dietary history and family history will all be collected. A physical examination will be performed to evaluate for signs of a kidney stone, such as pain in the flank, lower abdomen or groin.<br /><br />Your doctor will perform a urinalysis, to look for blood or infection in the urine. A blood sample will also be collected so that kidney function and blood counts can be measured.<br /><br />Even though all of these tests are necessary, a kidney stone can only be definitively diagnosed by a radiologic evaluation. In some cases, a simple X-ray, called a KUB , will be adequate to detect a stone. If your doctor requires more information, an intravenous pyelogram (IVP) or a computed tomography (CT) scan may be necessary.<br /><br />Sometimes kidney stones do not cause any symptoms at all. Such painless stones can be discovered when your doctor is looking for other things on X-rays. Sometimes, although a stone does not cause any pain, it can cause other problems, such as recurring urinary tract infections or blood in the urine.<br /><br />How can kidney stones be prevented?<br />If you have had one kidney stone, you are likely to form another. To reduce your chances of forming another stone, the first step is to determine why your original stone formed in the first place.We believe in the adage, “An ounce of prevention is worth a pound of cure,” so we place great emphasis on a thorough metabolic evaluation, so that therapies can be appropriately directed towards reducing the risk of recurrent stone disease.<br /> <br /><br /> <br />If you passed your stone on your own and still have it, your doctor will send it to a laboratory to be analyzed to see what it is made of. Usually, if your stone is removed by ureteroscopy or PERC , your doctor will send a piece of the stone for analysis too. The composition of a stone is an important piece of information to have, as treatment is specific to the type of stone.<br /><br />Because we know that kidney stones form when the urine has too high a concentration of crystals and/or not enough substances that protect against the crystals, a detailed analysis of the metabolism of a stone former is important.<br />Typically, the metabolic evaluation of a stone former consists of a simple blood test and two 24-hour urine collections.<br /><br />The results of these metabolic studies will provide an assessment of the risk of future stone formation. <br /><br /><br />How should my kidney stone be treated?<br /> <br />Historically, the treatment of kidney stones required major surgery and was associated with long hospitalization and recovery periods. However, in recent years an improved understanding of kidney stone disease, along with advances in surgical technology, has led to the development of minimally invasive and even noninvasive treatments for people with kidney stones.<br /><br /><br />جامعة المستقبل الجامعة الاولى في العراق<br />قسم تقنيات المختبرات الطبية الاول في التصنيف الوطني العراقي