Demystifying Kidney Disease for the Average Joe!

Uric acid is a substance found in the blood. It gets there when "purines" which are one of the building blocks of your DNA, are broken down. This is normal cell metabolism, and hence it is ok to see some amount of uric acid in the blood. However certain disease conditions, foods, and medications can also raise blood uric acid levels to abnormal levels. High uric acid levels, or "hyperuricemia", may lead to "gout/gouty arthritis", but these terms are not interchangeable. 

It is a fact we are all too well aware of. The world, as we know it, continues to grow fat. The popular press has done an excellent job of educating the lay person about the link between obesity and heart disease, high blood pressure, diabetes, etc. However, despite scientific evidence to the contrary, the effect of obesity on the kidneys’ function is less widely known. 

For many of my patients, it is hard to see the connection between chronic kidney disease (CKD) and low red blood count, or anemia. The two entities just seem so disconnected that one wonders, what would one have to do with the other? The key to appreciating this link is recognizing two fundamental principles; one, that the function of the kidneys extends to beyond just "making urine", and two, kidney disease has numerous repercussions that affect multiple organ systems. Well, one of these organ systems happens to be your body's machinery that makes red blood cells, known as the hematopoietic system. And the reason this machinery gets affected in kidney disease is because of the kidneys' function in producing a hormone called, erythropoietin.

Sometime ago, I had posted a brief overview of treatment of chronic kidney disease . However, one factor that does determine the progression of chronic kidney disease that I did not touch upon was the amount of "acid" in your blood, and its consequent effect on the kidneys.

Sometime ago, I had written a post exploring the role of alternative herbal medications in the treatment of chronic kidney disease . That post had evoked strong reactions, both for and against, from the readers! Which set me thinking...is there a role of alternative therapies in the treatment of high blood pressure? If yes, is it based on hearsay, or solid medical evidence?  Luckily, to make my job easier, the American Heart Association came out with an official statement addressing this issue early this year. This was published in the journal Hypertension . I will try to summarize this statement's conclusion's addressing the efficacy of approaches like acupuncture, yoga, meditation, etc in treating high blood pressure. Please note that these conclusions apply only to treatment of high blood pressure, and not to other health/psychological benefits that may be derived from doing these activities .   

This is one the commonest questions that I get as a nephrologist. The typical situation is a patient with advanced kidney disease that I see in the office. The patient is accompanied by a family member who is eager to donate their kidney to the patient, but is concerned about any potential health pitfalls.  Assuming you have a donor who is willing to donate you their kidney and is fit to do so (I covered the steps involved in kidney transplantation and the prerequisites for a potential donor here ), the donor as well as you would need to be aware of what donation entails, and what, if any, future health consequences can they expect. So assuming the potential donor has no major contraindications to kidney donation (these will include impaired kidney function, active infections, cancers, chronic lung/heart/liver/autoimmune disease, substance abuse, pregnancy, etc.), this is what they could expect:

When patients develop advanced kidney disease, medically called stage 5 CKD , they could begin to develop symptoms or signs of kidney failure, called uremia. Up to a certain point, your nephrologist will try and treat these complications medically as much as possible. However, as kidney disease progresses, the symptoms may no longer be amenable to medical treatment. At this point, you will need either dialysis or a kidney transplant. Image courtesy NIDDK

Pregnancy is a physiologic stressor on a woman's body. The cardiac output has to increase to keep up with the increased metabolic demands of the woman and the developing fetus. The blood flow to the kidneys increases. Changes in blood electrolyte and acid levels occur. These changes, among others, have implications for both the kidney's function, as well the state of the pregnancy. Hence, nephrologists typically try to answer two questions when assessing these issues: 1) How does kidney disease affect the chances of getting pregnant, and kidney disease's effect on pregnancy? 2) What effects does pregnancy have on the status of your underlying kidney disease?  Continuing on my last discussion about sexual and reproductive issues in people with kidney disease, lets carry this forward.

The damaging  effects of smoking on lung and cardiovascular function are well known. Does smoking have similar effects on the kidney function as well? If yes, what is the evidence to support that conclusion? Most recently, this question was addressed by two different studies, both of which were published in the Journal of the American Society of Nephrology. The first study I want to discuss came out from the Johns Hopkins University School of Medicine. Unlike a lot of its predecessor studies, this study was a prospective study (rather than a retrospective analysis of patients' charts), following about 23,000 patients over a span of 20 years. The results of this study clearly established that current cigarette smoking was a significant risk factor for development of chronic kidney disease (CKD). However, what was even more profound was that the attributable risk (difference in CKD rates between people who smoke and those who don't)  of CKD for smokers was 31%, which was...

I often get the question, "hey doc, do I need to be tested for kidney disease"? The answer would depend on whether you have the risk factors to develop serious kidney disease. Kidney disease is often called a "silent killer", because all too often, patients do not have any symptoms, period. A common misconception is that if you "make urine", your kidneys are healthy. This is not true. As you might have noticed in my previous post , the amount of urine you make is not necessarily considered a valid test of your kidneys' function. In fact, I personally have a lot of patients who are on dialysis due to kidney failure; yet they continue to pee out a liter of urine daily! I will talk about the symptoms of kidney disease later, but for now let's focus on who needs testing; knowing that you may or may not have the relevant symptoms.

Nephrologists typically would question you about your alcohol intake as part of a routine office visit.  Let's see why is that so? Humanity's association with alcohol dates back to antiquity, as evidenced by the now-famous discovery of the Stone Age Beer Jugs ! So for millenia, we have been using alcohol variously as a medication, an antidote, a source of inspiration for treatment of writer's block, a medium to make friends and political connections, etc. "I have taken more out of alcohol than alcohol has taken out of me", claimed Winston Churchill. I am not sure if that included kidney disease or not, but I do intend to explore that question today.  Does alcohol cause kidney disease? Image courtesy of arztsamui/FreeDigitalPhotos.net You would think that 9000 years of binge drinking would lead to some solid evidence about the association between alcohol use and kidney disease. Surprisingly, there are not a lot many good studies out there that have addre...

The short answer is, "probably not". So is this another one of those medical myths, then? I had a patient's relative ask me this question recently. They had driven up from Sarasota to see me for some other nephrological issue, when we got talking about the role of recurrent kidney infections in causing chronic kidney disease (CKD). Recurrent kidney infections (called pyelonephritis, which is a type of a UTI) are known to cause renal scarring. They might also be associated with genetic or developmental abnormalities that could be lead to CKD.  That is a separate discussion in itself, but for the time being, I wanted to delve a little bit in to whether cranberry juice is worth your money. This is another one of those "top ten" questions that nephrologists get all the time! Do cranberries prevent UTIs? Image courtesy of James Barker/FreeDigitalPhotos.net Jokes about cranberry juice aside, there do seem to be plausible biological mechanisms to suggest t...

For all these years, I have considered the good old recommendation of drinking "8 glasses of water daily" another one of those medical myths; an unsubstantiated idea that for some reason has come to be accepted as the gospel truth by all. Till date, not a single high quality scientific study has looked at whether this is indeed the appropriate amount of water to drink. Yes, dehydration is obviously harmful to the kidneys' function, and you should still drink according to the thirst/weather. Yes, drinking a good amount of water will prevent kidney stones. But, how do we know if the magic number is 6 glasses, or 8, or 10? Should the recommendation be a higher intake for my patients here in Bradenton, Florida, than for instance, someone living in Upstate New York?  Image courtesy of artzenter/FreeDigitalPhotos.net Even nephrologists and other physicians have been guilty of doling out this advice to their patients for the longest time.

Since we have been discussing kidney stones over the last few weeks, I wanted to highlight a few points about the diagnosis and treatment of kidney stones, as it pertains to patients . I am not going to get in to the technical details of what a nephrologist or a urologist would do. My idea is to emphasize what you can do to complement your physician's treatment plan. One of the perks of practicing nephrology in Bradenton, Florida, is that you get a pretty good experience seeing patients with kidney stones. Maybe it is the weather! Most patients that I see have already received a diagnosis of kidney stones (nephrolithiasis or urolithiasis) via imaging studies by the time I see them in my clinic. Imaging studies used to diagnose kidney stones include CT scans, X-rays, or ultrasounds. The latter two modalities can often miss certain types of stones (like uric acid), which is why CT scans are considered the "gold standard".

I had previously emphasized that the treatment of a kidney stone does not end with its passage or removal. Let's talk about why is that the case? Kidney stones could be of different kinds (the predominant types are made of calcium and oxalate). Why you form a stone, as well as what type of stone you form, depends on a number of lifestyle, dietary, and genetic factors. It could also depend on other disease conditions that have a bearing on the way stones form in the first place. Some of these factors might be treatable or modifiable, and hence prevention of future stone formation is possible if you can tailor treatment to those risk factors. Before we talk about why kidney stones form, lets talk briefly about how stone formation occurs.

I covered the short-term symptoms and consequences of kidney stones in my previous post. Let's talk a little about the long term consequences. A question that is often asked is whether kidney stones can lead to progressive kidney disease/kidney failure. This is not an easy question to answer; in fact it should probably be rephrased to say, "can kidney stones be associated with kidney disease/failure?" This is because current medical studies that have addressed this issue have proven association, and not causation. At least, not yet!

Stones in the kidneys are a common clinical problem. You might see this medically referred to as "nephrolithiasis" or "urolithiasis".  For reasons not fully understood, the prevalence of kidney stones seems to be increasing . This could be related to the increase in obesity rates, dietary changes (availability of cheap, high sugar, high salt fast foods), or maybe, even changes in the climate (global warming!). Warmer weather is a known risk factor for kidney stones; which is probably why their prevalence in southeastern U.S. is 31% higher than the northwestern region ! So what are kidney stones made of?

I see a lot of patients in consultation in my clinic who are, well, not quite sure why they are in my clinic! Usually, they would have been referred from their primary physician because they were deemed to have " chronic kidney disease , or CKD". A frequent refrain is, "Doc, I feel fine. I don't know why they asked me to see you?!"  The reality is that CKD belongs to that dreaded class of diseases called, "the silent killers". In other words, you may or may not have any symptoms! In the early stages especially, the only abnormality might be elevated creatinine or reduced GFR when your physician checks your kidney function . Some common misconceptions regarding kidney disease are that the kidneys "should hurt", or you "stop making urine". These are nothing more than medical myths.

I want the first post to address the absolute basics about the kidneys. Looking at this from a patient's perspective, I am often surprised by how little some of my patients know about the kidneys. I guess the lay press has a done a pretty good job of educating everyone about the other "more glamorous" organs! Everyone realizes the important roles played by the heart, the brain....even the liver gets its fare share of the limelight with everyone realizing the connection between liver disease and alcohol intake. The questions that I get asked often range from, "what do the kidneys do", "what/where are they", "why should I be worried about kidney disease"? "Image courtesy of [Dream Designs] / FreeDigitalPhotos.net" So here goes: