Kidney Disease : Part 2

by Food and Drug Administration (FDA)

(Page 2 of 3)

Unlike the acute form, chronic glomerulonephritis involves progressive kidney failure and is the most frequent cause of end-stage renal disease. In the early stages, the only sign that the patient is ill may be abnormal findings in a urinalysis typically red and white blood cells and protein in the urine. If the kidneys are beginning to lose function, the patient may have high blood pressure.

As the disease progresses, hypertension becomes persistent and difficult to treat. With severe loss of kidney function, patients experience diminished appetite, nausea and vomiting, extreme fatigue, difficulty sleeping, itching and dry skin, and muscle cramps.

Yet another kind of glomerulonephritis, rapidly progressive glomerulonephritis, is marked by accelerated kidney failure. It appears suddenly, is characterized by a decrease in urine output, and is irreversible.

Disease Product

Strictly speaking, kidney stones are not a disease but the product of a disease. Nevertheless, the more than 800,000 Americans treated for this ailment each year know that kidney stones can cause excruciating pain before they pass out of the body by themselves or are cut out on the operating table. Stones can be caused by hereditary factors, diet, occupation, metabolic disturbances, the amount of water a person consumes, and even climate. The fact is, scientists are not entirely sure why some people develop kidney stones while mercifully most don't. Nor do they understand why black people have far fewer stones than do whites or why three males are affected for every female.

Most kidney stones are hard masses of salt and mineral crystals deposited on the inner surface of the kidney. (Similar stones that form in the bladder or pass from the kidney to the bladder via the ureter are properly called bladder stones.) A stone that breaks loose from the kidney and passes through the ureter to the bladder and then through the urethra outside the body may go entirely unnoticed. About 90 percent of stones do that. But sometimes they lodge somewhere en route through the urinary tract and continue to grow. This leads to tissue damage, internal bleeding, and the exquisite pain that is the hallmark of a stuck stone.

Prevention and Treatment

Since many forms and individual cases of kidney disease are of unknown cause, it's hard to identify preventive measures. On the basis of experience, though, scientists think that increasing urine output by drinking fairly large amounts of liquids each day can lessen the risk of kidney stones. A better understanding of metabolic factors that seem to be involved in stone formation together with careful use of drugs to regulate body chemistry may soon make recurrent kidney stones a preventable condition.

The prospects for preventing the various forms of nephritis, whose causes are even less well understood, are not as bright. Keeping hypertension under control, however, can have a bearing on the risk of developing nephritis. Moreover, adequate control of blood pressure is crucial in the care of patients with kidney disease at every stage of their illness.

People with diminished kidney function benefit from avoiding a diet high in sodium and protein as well as careful control of minerals such as potassium, calcium and phosphorus. However, the value of diet in preventing kidney disease is uncertain. Diet isn't likely to lower the risk of developing inherited kidney disease, and it can?t help a baby born with a congenital malformation that will lead to kidney problems.

Treatment of kidney disease depends on several factors, among them the exact diagnosis, the stage of the disease, other illnesses that may be present, and the age and general condition of the patient. In some cases treatment may consist of little more than rest and dietary restrictions. In others, notably end-stage renal disease, the patient may benefit from such medical marvels as an artificial kidney (dialysis) or a kidney transplant, techniques that improve the quality of, and prolong, life for many thousands of kidney disease patients.

Kidney Stones. Stones that aren't causing any trouble, so-called silent stones, usually don't require treatment. Acute attacks, however, may demand hospitalization because the pain is so severe. In most cases, the stone is small, and the patient needs medication to control pain and instruction on how to recover the stone for examination when it passes.

If a stone gets lodged in the ureter, physicians may try to remove it in a basket-like device passed into the ureter through a cystoscope, a hollow tubular instrument that can be passed through the urethra to allow visualization of the bladder.

If a stone gets stuck in the bladder itself, it can be crushed by a tiny instrument inserted via the cystoscope. The fragments are either washed out or allowed to pass in the urine. For stones lodged inside the kidney, physicians can insert a needle through the skin of a patient under local anesthesia to create a passage directly to the stone. Instruments are then passed through this passage either to remove or break up the stone. Stones that are formed primarily of uric acid can sometimes be dissolved by the use of drugs. But if neither medicines nor specialized instruments can be counted on to work, surgery may be the only option.

Several years ago, FDA approved a device that uses high-intensity pressure waves traveling through water to disintegrate some kinds of kidney stones and enable them to pass out of the body on their own. Known as extracorporeal shock wave lithotripsy, the procedure may involve lowering a patient under local or general anesthesia into a tank of water in which a powerful electric or other source generates a shock wave that, with the aid of x-ray or sonographic imaging, is directed precisely at the stone to be shattered. Multiple shock bursts are fired at the stone, reducing it to fragments. Lithotripsy takes about an hour, and the patient is usually out of the hospital in two days some are treated as outpatients and can resume normal activities. (Patients who have surgery for kidney stones are generally hospitalized for several days and need up to five weeks to recuperate.)

Another lithotripsy technique that uses a laser instead of shock waves was approved by FDA in 1986. The laser, passed through a tube to the location of the stone, reduces the stone to particles the size of grains of sand that are then excreted. Laser lithotripsy is especially useful in treating stones in the lower ureter.

Nephritis. Treatment for the various kinds of nephritis aims chiefly at controlling kidney damage and dealing with the consequences of progressive kidney failure. It can and often does involve a combination of dietary restrictions, drugs, and, when the patient develops end-stage renal disease, dialysis and transplantation of a donor kidney.

About the Author

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