— Chrissy, Michigan Dialysis, a procedure that uses a special machine to replace the kidneys in filtering waste from the bloodstream, may reduce the daily urine output that a person normally produces. This happens because as the blood is filtered during dialysis, fluid is removed, thus reducing the kidneys’ traditional role. As a result many dialysis patients produce very small amounts of urine. However, dialysis does not prevent someone from urinating normally; it only reduces the total urine output, so that he or she may only need to urinate once a day, which is not dangerous. Some dialysis patients produce as little as one cup or less of urine each day, though urine volume is usually dependent on the underlying cause of kidney failure. Some patients continue to produce normal volumes of urine, which helps to manage their fluid balance. You should be able to get more information from your grandmother’s doctor, a nephrologist. This medical specialist is experienced in treating kidney disease and can provide insight into the cause of your grandmother’s kidney failure. Q2. My husband was told that he has cysts in his kidneys. The doctor doesn’t seem concerned, but my husband says that when he urinates, he sometimes feels as if he is being kicked in the back. He also has an enlarged prostate, so he urinates frequently. He had a prostate biopsy last year that showed no cancer, but his PSA level is elevated. What causes these kidney cysts, and are they in any way related to the prostate problem? Most kidney cysts are completely benign and, once recognized by either ultrasound or CT imaging, do not need additional follow-up. Some kidney cysts have genetic causes, but they have a characteristic pattern, occur in particular age groups, and are very rare. Benign cysts have well-established characteristics: an imperceptibly thin wall, no interior debris, and a clear fluid inside that has the same density as water. More complex cysts feature thicker walls and internal echoes, where areas of calcification, or hardened tissue, need further significant follow-up. Your husband’s urinary symptoms may be consistent with his age. Back pain associated with urination, on the other hand, is an uncommon condition. It may be related to the reflux of urine from the bladder to the kidney and would usually be associated with other abnormalities seen on X-ray. Kidney cysts develop as a result of the thinning and expansion of some of the tubular structures of the kidney. They are not related to prostate problems and occur with the same frequency in men and women. Q3. I have medullary sponge kidney disease and have passed stones of all sorts of colors, shapes, and sizes. Are there really different types of kidney stones, and if so, is the type I’m experiencing now (white in color) of any greater concern? — Kimberly, Kentucky Kidney stones do come in all sorts of colors. Many are white, but others are black, or come in various shades of color. Medullary sponge kidney disease can be associated with the formation of calcium oxalate stones, which come in a variety of shapes and sizes. More important than the color, however, is the composition of the stone, which can include calcium oxalate, calcium phosphate, and a number of other compounds. Treatments to prevent a recurrence of these stones will focus on the type of stone you have, its composition, and any underlying metabolic disorders that may predispose you to the formation of stones. For this reason, it’s important to involve a medical or surgical specialist in your care. Together, you can develop a long-term strategy for managing your medullary sponge kidney disease and for preventing recurrent kidney stone formation. Learn more about disease prevention in the Everyday Health Healthy Living Center.
