The video is my narrative walking tour through the site. To me it is the easiest way to learn what is here and how to find what you want. It runs 12 minutes.
A growing number of articles have videos that take you through the difficulties of the medicine and science. People seem to like them a lot, and I think they make it easier to understand the truly complex nature of stone disease and its prevention. The collected videos range widely from article based to long form presentations about major problems in stone disease. It is the fastest growing part of the site.
The kidney stone guidebook has links to everything on the site. When you open it from here or from its big tab on the home page, you will find ‘ARTICLES BY TOPIC’.
I have written a brief book about how kidneys transform our fluid and diet habits into stone forming urine in the course of their normal life preserving functioning. It is a free PDF. Help yourselves.
Multiple trials have given us a reasonable answer, although no trial has actually focused on this question. My best opinion after reviewing much of what is available is that vitamin D supplements do not raise risk of kidney stones by themselves but may when combined with calcium supplements. In fact the supplements may be the major risk. In the trials no effort was made to control diet sodium, so supplements could raise urine calcium. This site has uniformly recommended that reduction of diet sodium is important when calcium supplements are used.
Struvite stones produced by bacteria are among the largest we form. They can fill up the inside of an entire kidney collecting system and often require elaborate surgery. Here is the story of how certain kinds of bacteria produce them by using materials present in normal urine. Infection stones are completely different from all other kinds, easily overlooked, potentially very damaging to kidneys.
Well enough to know how to construct a kidney stone prevention diet, but that does not solve the problem of how to eat. One needs many meals put together to form what might be called a cuisine, a collection of recipes from which one can construct a week or a month of meals. Here, Jill Harris has done just that.
The details about the OTC substitutes for potassium citrate tablets. All of the products are useful but they differ from one another in a lot of ways so you might want to read about them before using. For patients, I say in the article and also here that even though they are OTC I advise using them for stones only with your physician’s oversight.
A foundational article, this tells about risks stones pose during pregnancy and what can be done to reduce or prevent them. As well, it reviews what links stone forming to preeclampsia, prematurity, and lost pregnancies. Much of the linkage is via shared risk factors such as obesity, hypertension, and kidney disease. The article also shows that pregnancy is a stone forming state, that more pregnancies raise risk of becoming a stone former. It is of high importance for any women planning pregnancy.
The renal papilla is where urine is supersaturated, stones form, plaque forms, plugs form. And right there, where all the action is, the tissue is abnormally dense on CT. Most think it is denser than normal because of plaque and plugs, which makes sense. High density predicts one will become a stone former – that makes sense as stones form on plaque and plugs. One year of high fluids – 2 liters extra water a day – and density falls to normal. Maybe the plaque and plugs dissolve, maybe something else. Whatever the reason, a fall in density seems a practical gauge of fluid treatment, because physicians can measure papillary density on any CT.
This crucial article now has the video it long needed. The topic is as important as it is difficult, and I am afraid the difficulties have reduced its value to those who most need it – patients. I did brush up the text but frankly it was pretty good as it was. The video tells the story and makes the main points as clear as I can make them. It integrates the physiology with how things need to be done in order to achieve the final cure one expects from this not uncommon cause of calcium stones.
Red meat has a bad rep it may not deserve. For example, it does not promote kidney stones. You would think it might. Protein can raise urine calcium excretion and that is a major stone risk. But over the range of intakes we encounter in normal life, between 0.8 and 1.2 gm/kg/day of protein, risk does not rise. I presume body builders who snack on protein bars and protein powders may raise their stone risk, but the data we have does not support that – even so, it is probably not a great idea. On the other side of the diet divide, veggies lower stone risk, a lot. Part of the reason is they have a lot of potassium citrate and other alkaline potassium salts. Part, they have a high water content so urine volume goes up. Eat your red meat – not a problem for stones. Eat your veggies, a real benefit. Did I mention dairy protein? No risk, maybe a little protective. The article has been updated from its original, and I made a video for it. You can watch the video or read the article, or both. Incidentally, I did the video because someone wrote in and asked me to. I told her I would do it, and here it is.
This is a core article on the site, completely rewritten and updated, with two videos, one comprehensive (19 minutes) and a shorter one with less detail (10 minutes). These are among the most difficult and complex calcium stone formers to evaluate and treat effectively. The article on brushite supersaturation that I wrote only a month or so ago was meant as a crucial underpinning for this clinical presentation. The article is layered with something of value for patients and their families and enough detail to interest physicians and scientists. It is fully referenced for an online review genre,
All modern 24 hour urine results include supersaturations for calcium oxalate and brushite – the latter usually labeled “Calcium Phosphate”. Brushite is uncommon in stones and tubule plugs, and absent from plaque. Calcium oxalate and hydroxyapatite are the actual stone crystals we worry about, and hydroxyapatite what plaque and most plugs are made of. But brushite seems to come before these two more prominent crystals, and actually promote them, both of them. As calcium oxalate and hydroxyapatite form they destroy the brushite like fire destroys the tinder that started it. The role of brushite in calcium oxalate and hydroxyapatite stones was discovered by basic scientists, and the importance of brushite supersaturation as a predictor of stones was subsequently documented epidemiologically. So it rests upon basic and empirical research. There is no risk to monitoring brushite supersaturation, and assuring that stone prevention efforts reduce it below 1 – under saturation. The benefit has not been proven by a prospective trial, but lacking risk I wonder why we need a trial. It is simply that we keep an eye on a measure clearly presented to all of us with every 24 hour urine.
Empirical research is the workman’s science, the gathering of facts from the world into usable form. It is everywhere. Think about gathering the data about COVID-19 – empirical. About all the microbes in the colon – micro biome. About temperature everywhere on the planet all year round to ascertain Global Warming. The assembling of facts as they are in the real world is difficult and fundamental. What you do with them is quirky, the business of any scientist – or businessman, for that matter, who can get access. On this site, the work of Gary Curhan may be the best example of real empirical research for stone disease, and it is of massive value for practice of stone prevention – the link is to only one of his contributions. What sets empiricism apart from excellent report of cases from a clinic, for example, is that facts reflect a sample taken from the world without bias, or with as minimal bias as possible, so as to represent how things are in general. People who do this are superb professionals, usually part of big teams. The reason is obvious – collecting a lot of data costs a lot of money and takes a lot of time – no room for beginners, and not a lot of tolerance for mistakes.
Video: Overview of Science
The pandemic is teaching us about how important science can be – new vaccines, new treatments, but also how confusing science can be: slow moving, and easy for people to misinterpret, unintentionally or not. Kidney stone prevention arises from science, and I have always based the articles here on what science we have. I practice the same way. But it seems to me time to make science more obvious to people in general, and here to those people on this site because of stone disease. I have taught science to physicians for nearly 2 decades, and have made some videos about how it works. I aimed them at physicians but realized along the way that people with clear minds can just as well view them and get an idea about science – perhaps clear away some of its mysteries, and become more critical of what it offers. This is the first video, an introduction. I have more coming, one each week, for five more weeks.
Stone prevention often requires diet changes: lower sodium, oxalate, sugar and protein, and higher calcium and potassium intake. The idea is clear enough, and given food labeling the same for shopping. But how do you prepare tasty meals that meet the requirements – where do we get recipes? Here is a new collection by Melanie Betz, a well credentialed medical nutritionist who works with kidney disease patients at University of Chicago. They are correct in quantity. As to their appeal, I await the judgement of all of you. Please comment if you make any of her offerings.
Passing stones can obstruct a kidney. Obstruction reduces the function of a kidney and can injure it, even to the point of destroying tissue. CT scans and ultrasound can tell if a kidney is obstructed. Likewise, repeated studies can follow the progress of a stone down the ureter and into the bladder. But how long to wait is not so obvious. I found only a few reliable human studies of the matter and review them here. Likewise, I review evidence that kidney tissue can be lost with even moderate obstruction, and it does not come back – kidneys cannot replace lost nephrons. I view the matter of timing as unsettled and in need of more research. But for the moment it is possible to suggest a reasonable range of upper bounds on ‘how long’.
Crucial for large stone burdens, PERC is a complex surgery, one of the three main stone surgery modalities. Luke Reynolds was kind enough to write this helpful and well referenced article about how and why PERC is performed. What he wrote is especially valuable for patients who must help choose their best surgical option given the stones, anatomy, and myriads of other factors that determine if PERC is the ideal for them.
This article originated 3 years ago and it is so important I completely rewrote it into a new article. We know more and I wanted people to know. I wrote it better. The new is more charming and clear. I made a video, too, as people like them. The video has a built in recommended stopping point for a break. IH is bedrock knowledge for calcium stones. Much of what we do is to lower the urine calcium, and most of the reason for high urine calcium in calcium stone formers is IH. It puts bone at risk, too, and I have included the most important trial for bone related to what we do for IH. I am planning a deeper article on the science of IH.
Children form stones, not rarely, and have special needs. This article focuses on their 24 hour urine risk factors and recurrence rates. I do not cover the many rare genetic causes of childhood stones – saved for another time as it is a topic of its own. I also do not cover the surgical issues in children as I am not a surgeon and I have no one who can write if for me right now. Volunteers??
Not all true knowledge matters equally. Here is a nugget of three facts that matter more than much of what is on this site. It is a magic triangle of actions, in a special sequence, that can prevent stones and protect bone mineral stores. Like all magic spells you need to do it in a special way and not make a mistake, because you are doing things with real power, for good or bad. So read this and pay attention. The details, the science, are linked for anyone who wants them. For everyone who wants good prevention, these three steps, properly done, can be invaluable.
Most diseases have a common age at onset and stones the same – about 30 or so. Like most diseases, this one has its range, young and old. Here is about the latter, people whose stones begin on the last side. Why care? Partly people are curious. But as we looked into the matter there are special meanings to a late start. Some diseases are more prevalent. There are a few precautions. All in all it is good to keep this matter in mind. If you are one of the late ones, take a look.
When women and men eat the very same food, the women absorb from the food more alkali. As a result, for any amount of acid load our Western diet imposes they do better. Their selective absorption of alkali helps offset the diet acids. Acid loads are not a good thing. Experts in many fields link acid load to worsening glucose tolerance, bone mineral loss, kidney disease, hypertension, and even reduced longevity. By raising urine calcium, diet acid load certainly can raise risk of kidney stones. On top of that, women tend to eat foods with more alkali, like fruits and veggies. The dark side – there is always one, it would seem – is that when they do form stones women are more prone than men to form calcium phosphate stones. Phosphate stones are more likely to get larger, and numerous. So women have special powers and also special risks. Physicians need to know that, and so do they.
We know forming stones indicates above average risk for high blood pressure, and for kidney, cardiovascular, and bone disease. We also know that our modern diet promotes all of these diseases. Finally we know that not everyone responds to the diet by becoming ill – many seem relatively unaffected. This leads me to propose the idea of linked diet disease susceptibilities: stone formers are susceptible not only to stones but to an entire manifold of cardiovascular, renal, and bone diseases promoted by our present unhealthy diet. If true this speculative idea means that failure of stone formers to improve diet may be more harmful than in the average person, not just because of stones but because of the entire manifold of diseases, many far worse than stones. Scientists need to test the idea, but that will take time. As we wait on science’s progress, we need to highlight that dietary stone prevention is always important. Medications and fluids, valuable as they are, need to be in addition to, never in place of a correct diet.
Counting new stones right is absolutely necessary. You can’t sail a ship, or fly an airplane, or drive to the shopping mall without keeping track of where you are, and the same for stone prevention. New stone counts tell us if a patient is an active stone former or not, and if our treatment is a success or a failure. New stones are those passed or removed, or seen on an image, and not present on a prior image – radiographic or ultrasound. To know new from old requires, therefore, we read our images correctly and correlate stone numbers in time with stone events. Physicians have ultimate responsibility for counting right, but patients can help immeasurably by keeping track. This is how I count new stones, and I believe it is a correct way.
Recent epidemiology has linked forming stones to these dire conditions. Increase in risk is not large, but seems undeniable. The increase is most evident among younger women perhaps because their baseline risk of vascular disease is lower than that of men, but it can be seen in both sexes. These new facts add weight to the need for comprehensive care of all stone formers. As a group they have increased risks for bone disease with fracture, hypertension, kidney disease, and now we know for stroke and heart attack. We have no information about whether prevention of stones helps reduce these risks, but certainly it can do no harm.
Lower is better – that is the main burden of the new US hypertension guidelines. This applies to all of us. But kidney stone formers have a special place because their diet and treatment needs for stones closely overlay with those for blood pressure. The good part is synergy: If careful, treatment for the one will do for the other. The alternative is a piling up of treatments that eventually tire patients and lead to dropout. In this article I detail how to do the better way. The article is long because it includes home blood pressure techniques, and the evidence for lower treatment goals. But it is worth the read. Lower blood pressure saves lives, prevents strokes. It is so important. Give it your time.
We cannot ignore the excellent body of work that has disclosed undeniable associations between stone forming and significant bone, hypertensive, and kidney disease. Multiple investigators have found that having stones predicts higher risks we need to mitigate through treatment that can both reduce stone forming and protect against fractures, high blood pressure, and kidney disease. The main stay of such treatment is the kidney stone diet. It so much resembles the diet recommended for all Americans I cannot but say every stone formers should adopt it. While incomplete treatments like very high fluid intake, or perhaps rigorous low oxalate diet may stave off stones, they fail to address the range of diseases to which stone formers are more prone than otherwise normal people. There is no sense to such incomplete measures when proper diet can do so much more.