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Renal calculi (nephrolithiasis) are stone-like masses formed in the kidneys. Normal urine contains predictable amounts of calcium, magnesium, uric acid, and other by-products of metabolism. These normally remain in solution and pass from the kidneys down the ureters to the bladder and out of the body. These minerals and by-products form crystals on the inner surfaces of the kidneys when urine becomes too concentrated. Over time, these crystals may accumulate to form small, hard, stone-like particles in the kidney.
Many cases of renal calculi have no identifiable underlying cause; however, risk factors for developing kidney and ureteral stones include lack of fluids (dehydration), family or personal history, certain medications such as diuretics and indinivir (a drug used in the treatment of HIV), diet, and sedentary lifestyle. Rare, inherited diseases such as renal tubular acidosis and cystinuria are associated with calculus formation as are gout, blockage of the urinary tract, urinary tract infection, excess intake of vitamin D, polycystic kidney disease, and hyperparathyroidism. Intestinal bypass procedures and ostomy surgery are associated with an increased incidence of stone disease.
Risk: Men are more likely to develop stones than women, although the number of women with the condition is rising. Whites are more prone to develop calculi than blacks. Incidence and Prevalence: Five percent of Americans will develop urinary stones at some point in their lives ("Management"). |
Source: Medical Disability Advisor
| History: Symptoms vary according to the site and size of the stone. Small kidney (renal) stones frequently cause no symptoms until they start to pass down the tube that carries urine from the kidney to the bladder (ureter). The resulting pain (renal colic) is excruciating and intermittent. Individuals may report pain that starts on the far right or far left side of the back (flank), and that then moves toward the groin. The severe pain may precipitate nausea and vomiting. This can then result in significant fluid depletion (dehydration). Bloody, cloudy, or foul-smelling urine may be noted. Fever, chills, and frequent urination may also be reported. Physical exam: The individual may appear to be in severe pain. This may result in blood pressure elevation. Tapping softly on the flank worsens the pain. Light pressure applied with the fingertips (palpation) to the lower abdomen may reveal an enlarged and tender bladder (bladder distention). Tests: Microscopic examination of the urine may reveal large numbers of red blood cells (hematuria), white blood cells (pyuria), and the presence of crystals. A urine culture should be performed to check for evidence of infection. X-ray studies of the kidneys, ureters, and bladder (KUB) can confirm the presence of most renal calculi and show the site of the stone. The most definitive test is an x ray of the kidneys taken after contrast medium is injected into the arm (intravenous pyelogram, IVP). This test can confirm the site of the stone and indicate if there is obstruction of the urinary tract above the stone. Obstruction can also be monitored by ultrasound scanning and by computed tomography scanning (CT scan). |
Source: Medical Disability Advisor
| The majority of small stones (less than 5 millimeters in diameter) are passed into the urine with relatively few problems. Fluid intake is increased to encourage the passage of the stone from the kidney, through the ureter, into the bladder, and out through the urethra. Walking is also encouraged as this facilitates stone passage.
Approximately 20% to 30% of kidney stones are not spontaneously voided ("Kidney Stones"). Treatment may be necessary when a stone does not pass after a reasonable period of time and causes constant pain, or if a stone is too large to pass naturally. Treatment is also required when a stone blocks the flow of urine; causes ongoing urinary tract infection; damages kidney tissue or causes bleeding; or has enlarged. Several treatment modalities may be considered.
Extracorporeal shock wave lithotripsy (ESWL) uses shock waves originating outside the body to fragment stones, making them small enough to pass with urination. This is usually performed with general or local anesthesia. A stent may be temporarily inserted into the ureter to assist in locating the stone and helping the fragments pass following treatment. This is the least invasive procedure but may need to be repeated, as ESWL may not eliminate all stone substance.
Ureteroscopy (URS) involves the use of a ureteroscope, a tube that is inserted into the ureter by cystoscopy. This allows the urologist to directly view the stone. Various devices can then be passed into the ureter in order to remove or fragment the stone. This procedure is usually performed under anesthesia. A stent is left in the ureter for several days after treatment.
If a stone is in a location that does not allow ESWL or results in blockage that cannot be bypassed with a stent, a surgeon may need to perform a percutaneous nephrolithotomy. Through a small incision in the flank area, an instrument called a nephroscope is used to locate and remove the stone. For larger stones, a type of energy probe (ultrasonic, electrohydraulic or hydraulic) may be used to shatter the stone. This is performed with sedation or general anesthesia.
Open surgery for stone removal is rarely necessary. This is the most invasive form of treatment. In open surgery, the ureter and/or kidney are exposed and the stone is directly removed.
If a stone is caused by a metabolic disorder, the individual may be treated with a diet and drugs to lower the urine content of the substance from which the stone was formed. Increased fluid intake may be necessary to not only dissolve existing stones, but also to help prevent a recurrence. Stones associated with hyperparathyroidism are also treated by removing the parathyroid tumor responsible for the condition. |
Source: Medical Disability Advisor
| In most cases, the outcome of treatment is excellent whether the stone passes without incident or the individual requires a procedure to effect stone removal. However, people who have had one kidney stone are more likely to develop others. Approximately half of the individuals treated for a renal calculus will have a recurrence within 5 to 10 years and 80% have a recurrence sometime during their lives ("Kidney Stones"). |
Source: Medical Disability Advisor
| Renal calculi may be associated with recurrent episodes of urinary tract infection. Any obstruction to urine flow may result in rapid kidney damage or severe kidney infection (pyelonephritis). |
Source: Medical Disability Advisor
| Individuals who are in the midst of passing a kidney stone are unable to work, but may resume work once the stone passes. Those who have jobs in which the sudden and severe pain from a calculus could put them at risk (such as heavy-equipment operators, construction workers, or those who do heavy lifting) may need to stay home or be assigned less dangerous duties when experiencing kidney stone problems. Individuals with stones may require restrictions on bending, stooping, and heavy lifting. All will require frequent access to fluids to aid in hydration. Those who are hospitalized will need from several days to weeks for recovery, depending on the procedure performed while in the hospital. |
Source: Medical Disability Advisor
| If an individual fails to recover within the expected maximum duration period, the reader may wish to consider the following questions to better understand the specifics of an individual's medical case. Regarding diagnosis:
- Has diagnosis of renal calculus been confirmed through x-ray studies, ultrasound scanning, or CT scan of the abdomen?
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Has intravenous pyelography (IVP) been done to determine site of the stone and whether there is obstruction above the stone?
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Has urine culture been done to determine the presence of an infection?
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Has individual experienced any complications associated with stones in the kidney or ureters?
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Does individual have an underlying condition such as a metabolic disorder or hyperparathyroidism that may impact recovery?
Regarding treatment:
- Does discomfort persist despite the passage of small stones? Could additional, larger stones still be present?
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Was ESWL successful in disintegrating the stones into pieces small enough for easy passage? If not, was ultrasonic lithotripsy, electrohydraulic lithotripsy, or laser lithotripsy utilized?
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If not successfully removed via ureteroscope, what procedure was used for removal of stone from ureter?
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Has individual been compliant with prescribed diet, drug therapy and increased fluid intake? Have stones recurred?
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If stones are associated with hyperparathyroidism, have one or more of the parathyroid glands been removed? Has this been effective in correcting the metabolic abnormalities of hyperparathyroidism?
Regarding prognosis:
- With larger stones, or if an infection or obstruction to the urinary flow is present, was surgical intervention required to prevent damage to kidney? What is the prognosis associated with that specific procedure?
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For what reason has disability persisted beyond expectations?
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Does individual have a history of renal calculi? What can be done to reduce risk factors for future recurrence?
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Source: Medical Disability Advisor
| "Kidney Stones." American Foundation for Urologic Disease. 31 Aug. 2004 <http://www.afud.org/conditions/kidneystones.asp>. "Management of Ureteral Stones." UrologyHealth.Org. American Urological Association. 30 Aug. 2004 <http://www.urologyhealth.org/adult/index.cfm?cat=12&topic=105>. |
Source: Medical Disability Advisor
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