Ask the Experts
These questions and answers have appeared in previous issues of PKD Progress, the PKD Foundation's quarterly magazine. The information below is provided by members of our Scientific Advisory Committee.
This section of the website will be updated frequently, and we encourage you to submit your own questions for our doctors by filling out this form. Please keep in mind these questions will not be answered immediately but will be passed on to a medical expert for review. Responses will be posted to the website - not sent to individual patients. For immediate personal health concerns, please consult your nephrologist.
WINTER 2007
Q: What pain medications can PKD patients safely use?
A: Do not use NSAIDs (non-steroidal anti-inflammatory drugs), because these compounds are nephrotoxic or damaging to the kidneys. NSAIDs include Ibuprofen, Aleve, and Motrin. PKD patients can use Tylenol 650-1000 mg as often as 4 times/day. If this does not handle the pain, Tramadol, Clonidine, or Amitriptyline may be added with the Tylenol on the advice of your doctor.
Q: What is genetic testing?
A: Determination of the mutation you carry can be done by direct DNA analysis, using a blood sample from the patient or by linkage analysis, which involves analyzing blood samples from a number of affected family members.
Q: What are the negative consequences of genetic testing to determine if you have a mutation in the PKD1 or the PKD2 gene?
A: The test is costly ($1,200-1,500). Since it involves having blood drawn by your doctor and being sent to the testing facility, the results become part of your medical records. As a result, there may be insurability problems at a later date, because PKD may be considered a “pre-existing condition” by insurance companies.
Q: Can Tolvaptan (now in Phase III clinical trials) be used “off label,” that is, for a condition for which it is not currently approved by the FDA?
A: Tolvaptan is not yet approved for any clinical condition at this time, so it cannot yet be prescribed at all. It is likely to be approved within the next few years for use in hyponatremic situations. Once it has received FDA approval, it can be used “off label.” It is strongly recommended that Tolvaptan not be used off label for PKD until research studies demonstrate that it works and that it is safe.
Q: Please explain the current use of steroids as anti-rejection medication post transplant.
A: The dose of steroids used to prevent rejection following transplant has been reduced since the early days of their use. It is common now for patients to have their dose reduced with time after transplant. It is not yet known if it is possible for a transplant recipient to get off of steroids completely. Many programs now avoid steroids completely or taper them very rapidly after the time of transplantation. Good outcomes have been reported up to at least five years after such protocols, however, the very long term outcome of using no steroids is not known completely.
FALL 2007
Q: I find it difficult to do most cardio exercises. Are there alternate forms of exercising that are beneficial to PKD patients, such as yoga or Pilates? If so, what are the best alternate forms of exercise and which ones aren’t so good?
A: There is little information regarding risks and benefits of exercise specifically in individuals with PKD. Thus, there is no real basis on which to recommend one particular type of exercise over another. In patients with chronic kidney disease, limited studies have suggested potential benefits of regular physical exercise including improvements in exercise capacity, strength, quality of life, blood pressure, diabetes, and survival. The relative benefits of aerobic exercise and resistance exercise remain to be defined, although studies have shown benefits in both.
Much of what is believed to be true regarding exercise in individuals with chronic kidney disease is extrapolated from studies in normal individuals. Even in normal individuals, it remains to be determined how the interrelated characteristics of amount, intensity, duration, frequency, type and pattern of physical activity are related to specific health or disease outcomes. Recommendations have generally focused on cardiorespiratory endurance and specified, sustained periods of vigorous physical activity involving large-muscle groups (activities such as walking or cycling) and lasting at least 20 minutes on 3 or more days per week. More recently, national organizations have recommended regular, moderate-intensity physical activity (30 minutes or more on all, or most, days of the week) as an option for those who get little or no exercise. Studies have even suggested benefits when physical activity occurs in several short sessions rather than one longer session. Moreover, for people who are unable to set aside longer blocks of time for physical activity, shorter episodes are clearly better than none.
The body responds to physical activity in ways that have important positive effects on musculoskeletal, cardiovascular, respiratory and endocrine systems. These responses have been associated with a number of health benefits, including a reduced risk of premature mortality and reduced risks of coronary heart disease, hypertension, colon cancer and diabetes mellitus. Regular participation in physical activity also appears to reduce depression and anxiety, improve mood and enhance ability to perform daily tasks. Flexibility exercises, such as stretching or yoga, could help maintain or improve range of motion and might also improve gait, balance and coordination.
The risks associated with physical activity must also be considered. The most common health problems that have been associated with physical activity are musculoskeletal injuries, which can occur with excessive amounts of activity or with suddenly beginning an activity for which the body is not conditioned. More serious health problems (e.g., heart attack, sudden death) are much rarer, occurring primarily among sedentary people with advanced atherosclerotic disease who engage in strenuous activity to which they are unaccustomed. Prior to embarking on an exercise program, individuals should be screened for signs or symptoms suggestive of cardiac disease. Exercise should begin at low intensity and short duration, with increases in both as the individual tolerates. Warm-up and cool-down sessions of 5 10 minutes should precede and follow each session.
Additional information regarding the health benefits of exercise can be found in a report of the U.S. Surgeon General at www.cdc.gov/nccdphp/sgr/sgr.htm.
Q: I am a 19-year-old male who has PKD. I used to do a lot of strength training and would like to get back to lifting regularly. Are there some lifting guidelines that I should follow, such as how much is safe to lift, how often can I lift, should I do fewer repetitions, and are there any types of lifting that I should avoid?
A: Once again, there is limited data in this regard specific to PKD. In general, resistance training should be initiated at low intensity and progressed gradually as tolerated. With gradual progression, it is not clear there is a maximum weight that can be lifted safely. However, there is an increased incidence of abdominal and inguinal hernias in individuals with PKD, and thus excessive straining of the abdominal muscles should be avoided to the extent possible.
SUMMER 2007
Q: If I have PKD, is it safe to breastfeed my child?
A: Evidence for positive health effects of breastfeeding has been increasing over the last several decades. The clearest benefit is protection against infectious diseases. It has also been suggested that there is a relationship between breastfeeding and long-term effects on development and risk of later diseases, although a direct cause-and-effect relationship has not been demonstrated. There is no evidence that there is any detrimental effect to breastfeeding if a mother has PKD, but the usual caveats would apply (for example, the mother should make efforts to maintain adequate nutrition and adequate hydration). It should be noted that selective medications, when taken by the mother, will appear in the breast milk and may be absorbed by the infant. Thus, a new mother who anticipates breastfeeding should seek counsel from her physician regarding what medications are safe during breastfeeding. This same concern would apply to pregnancy in general. Numerous medications, including those used frequently in patients with PKD (ACE inhibitors, angiotensin receptor blockers, statins), can have adverse effects on the fetus and are contraindicated during pregnancy. The best advice is to consult your obstetrician regarding medications during pregnancy and breastfeeding.
Q: How many years should a transplanted kidney last before it begins to fail?
A: There are many factors that affect the duration of useful function for a transplanted kidney. Statistics typically look at the duration of graft function until a patient needs to return to dialysis. Many factors affect this, including recipient ethnicity, recipient age, the etiology of the recipient’s kidney failure, HLA (tissue) matching, donor age and, probably most importantly, donor type (living donor versus deceased donor). In general, patients with PKD are very good candidates for renal transplantation and have graft-survival rates that are as good as or better than patients with renal failure due to other diseases. Advances in immunosuppression have decreased the risk of immunologic recognition of the foreign kidney (rejection) and have led to significant increases in early graft survival. In addition, with modern immunosuppression, the survival of living donor kidney transplants is not dependent upon a genetic relationship between donor and recipient. Currently, at the end of one year, approximately 95% of living-donor renal transplants are still functioning, and approximately 89% of deceased-donor renal transplants are still functioning. In spite of improved immunosuppression, ongoing graft loss over time continues to be a significant problem, with approximately 5-10% of grafts lost each year. At the end of five years, approximately 80% of living donor renal transplants continue to function and 67% of deceased donor renal transplants continue to function. At the end of 10 years, approximately 57% of living-donor renal transplants and 41% of deceased-donor renal transplants continue to function. Additional information can be found at http://www.ustransplant.org/ and http://www.unos.org/.
Q: My daughter’s boyfriend has ADPKD. My concern is that he smoke cigarettes. What are the implications of this to his future health?
A: Cigarette smoking has adverse affects on multiple organ systems, including the lungs and cardiovascular system, of which the kidneys are a part. Cigarette smoking increases the likelihood of lung cancer and increases the frequency of heart attack, stroke and chronic kidney disease. Cigarette smoking increases the rate of deterioration of chronic kidney diseases of all types, including that caused by polycystic kidney disease. Cigarettes are clearly addictive, and smoking cessation is truly a challenge. Nonetheless, there are significant health benefits to smoking cessation, and seeking the help of a physician or other health professional is recommended.
SPRING 2007
Q: Research in ADPKD animal models suggests soy protein may have a beneficial effect on delaying the progress of renal disease. Does this mean I should eat a lot of soy?
A: The statement “eating a lot of soy” means only that you can eat as much soy as you wish as long as you stay within the guidelines for total protein intake. Soy protein should be counted as part of your protein allowance. At this point, the safe recommendation is to substitute soy products for animal protein (meat and dairy products). Soy protein has been shown to have an increased benefit over the other forms of protein in animal models of polycystic kidney disease. The effect was moderate. Research is being conducted to delineate the specific beneficial components in the soy proteins that retard PKD. Phytoestrogens were once thought to be the beneficial compound, but research has determined that this is not the case. Currently, sapsonin B is being investigated, and if found to be beneficial, will be certainly tested further in humans with ADPKD.
Q: My wife has been treated over the past 15 years or so for PKD. Lately, she has been, with the consent of her nephrologist, using fish-oil supplements as well as flax seed. Do you know of any research showing benefits to patients who use flax seed or fish oil?
A: Investigators in Canada have demonstrated the value of dietary fish and flax oils in a number of renal diseases in experimental animals. Fish oil and flax oil are excellent sources of a type of fatty acids (omega-3-fatty acids) which are thought to have anti-hypertensive, lipid-lowering and anti-inflammatory effects. Fish oil, however, did not have a beneficial effect on early disease progression in a strain of mice with polycystic kidney disease (pcy mice). Histologic studies revealed that flaxseed feeding in the Han:SPRD-cy rat was associated with a modest reduction in cyst change.
Q: I am 62 years old, and I have PKD. My physician has told me that my renal function is beginning to decline, but that it may still be a few years before I need dialysis. Is there an age limit for renal transplantation?
A: In the United States, there is no formal age limit to renal transplantation. There is some concern that, as people get older, there are more illnesses or medical conditions present that make the possibility of a successful transplant less likely. During the transplantation evaluation performed on every applicant, there is a greater likelihood that there will be a medical or surgical contraindication to transplantation (such as cancer, significant heart disease, etc.).
Q: I saw my gynecologist because of irregular menstrual cycles and was diagnosed with polycystic ovary syndrome. Is this related to polycystic kidney disease? Are patients with PKD more likely to have polycystic ovaries?
A: Polycystic ovaries are a separate clinical entity associated with facial hair, acne and infertility. This form of polycystic ovaries is not associated with ADPKD. However, in women with ADPKD, cysts in the ovaries can develop. They are not related to polycystic ovary syndrome. The treatment of polycystic ovaries unrelated to ADPKD usually includes the use of birth control pills. As well, the polycystic ovaries can be treated by taking a small piece of tissue out of the polycystic ovary. If birth-control pills are used, it is wise to undergo imaging of the liver to determine if significant polycystic liver disease is present. If so, one might consider wedge resection of the polycystic ovary instead of birth-control pill use. Currently, polycystic ovaries in PKD have no known associated abnormalities and are not treated unless large enough to cause pain. If this occurs, removal of the ovary is often considered.