A particular manner

Here and there physician friends have asked me about how I practice. But however much I have written about kidney stones, nowhere before have I told about how I practice because I feared my style might seem too odd. But it is not if you consider how narrowly I have chosen to focus.

My clinical life is based on several facts. One is that doctors send me their patients and expect that I will prevent recurrent stones. That is all they want from me. This means that I can depend on other physicians to do everything else, focus on the pathogenesis of kidney stones in a particular patient and fashion for that patient a program of prevention which will disrupt that pathogenesis and reduce or possibly abolish their illness.

In the title of this post, I say ‘art’ because physicians are makers. We make a treatment plan for every patient that will result, in this case, in less stones. In the making of such plans, I use only a few remedies, which most of you know about, but I probably use them a bit differently from most.


Although I have seen about 6,000 stone patients, I still take a very long time with each one. New patients require an hour or more, and it might surprise you to know that many return visits can take as long or longer. Such lavishness would be unreasonable in the broad world of medicine, only in a world like mine, subsidized by a tolerant university and the willingness of our culture to support a few odd sojourners like me can someone lavish so much time on one task.

The time is partly to get the history right. Stones arise through a compound of inheritance, habit, accident, and chance, and no two patients are exactly alike in how they became stone formers. Although I have not written any proof of it, no two have the very same treatment programs if you consider not just superficial aspects of diet and drugs but the details of life and work and habit that need to be altered. It is in those details, in the thick of the brambles, I usually find the real reasons for stones and, having found them, fashion my treatment plan around them. This patient did some odd thing, that one something else, for a while or for a lifetime, and will not tell me right away. Some do not know what caused their stones. Some know very well but will not tell unless I stumble on it. That is where the variety hides, and where I spend a lot of time.

The rest of the long time I take is used in explaining and in finding ways to change things, for I must bring about a change in life. It sounds easy if you have not tried it, but most of you know it is not easy. Patients will always acquiesce on the moment, and then do as they desire. I must somehow change their desires or fail. And these desires are about important matters: How they work, how they eat, how they entertain themselves, how they strive to remain healthy. I know that much of general medicine concerns itself with healthy habits, but my work is not like that. It is not general, but so particular as to reach into the detailed reality of the lives as lived, and it is there one meets with beliefs and resistances, and desires, and habits.

What crystals know

Of course it is not behavior that makes crystals from, it is urine chemistry. I use the standard 24 hour urine to gauge the immediate forces that control crystallization and use my clinical history to understand what aspects of life have affected those forces and which of them might be alterable. Everyone does this, I simply do it with unusual focus as it is all I do.

Consider this patient.

A woman of 42 began forming stones at 32, not an unusual age. Her latest stone was in the past year, and in between the first and last she had 4 other episodes. For her stones she has had 3 SWL procedures, and one ureteroscopic removal. An early stone report showed calcium oxalate dihydrate with 15% hydroxyapatite. A more recent stone analysis reported 45% calcium oxalate dihydrate, 5% brushite, and the rest hydroxyapatite. A recent CT showed bilateral universal papillary and perhaps medullary calcifications varying from 1 to 5 mm. A brief trial of hydrochlorothiazide some years prior had resulted in hypotension and the drug was stopped within 3 months. She had been advised to maintain a high fluid intake, which she said was her habit.

Her mother, who had herself developed premenopausal osteoporosis, urged calcium supplements on her which she used from her early twenties. She became a nurse, and in her mid twenties specialized in orthopedic surgical work. She married and had two children at ages 33 and 35, which interrupted but did not stop her nursing career that continued through a combination of day care and willing grandparents. When stones began she stopped the calcium supplements, and went on a low calcium diet. Her husband is a skilled pipe fitter with steady work in a foundry.

As I do in all cases, I obtain the blood and urine laboratory results I will need in advance of the visit so they are available without needing yet another visit. So when I had finished with the initial  history, I had the labs ready. Her blood chemistries were normal – in particular she was normocalcemic. Her 24 hour urine studies – I do three, not two as is more common – showed mild hypercalciuria, mild hyperoxaluria, a volume of above 2 liters, a pH of 6.5 on average, and only modest supersaturations with respect to both calcium oxalate and calcium phosphate. Urine sodium excretion averaged 175 mEq/day. Her urine calcium excretion varied with her urine sodium excretion in an obvious manner, as I commonly find. I made her a little graph to illustrate the point.

What life does

Of course, this is a patient with sodium dependent, genetic – idiopathic – hypercalciuria which may have been worsened by maternal advice and lessened by low calcium diet. As expected, she had modest osteopenia – I ordered a DEXA scan as any of you would do. The natural initial treatment would be low sodium, high calcium diet since thiazide had already proven troublesome and her calcium excretion was sodium dependent. But her work made me suspicious: how did she achieve her ample urine volumes being a surgical nurse? One of her three collections was on the weekend but I had insisted that two be during working days and the volumes at work and on the weekend matched reasonably well.

The answer, which took some time to get to, is that she drank after her long cases – one or two cases a day – and in the early evenings. The high sodium was from everywhere. Her husband and she were so busy that ‘food’ was ‘take out’ most of the week, and she, being in a hospital much of her day, snacked, as nurses do, on pretzels, chips, and peanuts. Willing as they were, the grandparents could not cook for them to any great extent, and, in fact, had high sodium food habits of their own. So, how can I treat her in a way that will work? How will she achieve constant high fluids, much reduced diet sodium, and much increased diet calcium?

What I did

This is a sophisticated nurse. She knew her fluid intake was variable to an extreme because of surgery and suspected the low extremes were promoting her stones. But she did not tell me. I had to ‘find out’ by going through her meals and what she drank with each, her work schedule, the nature of her cases, and even her snacks before the obviousness of the fluid problem led her to tell me she certainly knew daily intermittent dehydration was a problem.

She knew surgery was causing a dehydration problem, but she was the larger wage earner of the pair, so less surgery was not an option and she did not want it to come up with me. As for her diet, she did not know that high sodium intake would raise her urine calcium, or that combined with a low calcium diet would reduce bone mineral balance; but she did know the family ate badly. This latter she did not tell me until I had asked after all her meals; she knew there was no time to cook or shop properly but given the work she and her husband did what could be done about it?

Of course, making a way for her was not easy. It was all about the nearly impossible realities of two busy people. I did find ways, and her followup urines showed more calcium than at the beginning – higher calcium diet, somewhat less sodium, less oxalate – the low calcium diet and peanut snacks had raised her urine oxalate, and the same volumes. So on average her supersaturations were not better. But she assured me that the urine volumes were steadier throughout the working days. Over time she pushed the sodium down, the volumes up, and saturations fell more. Because of her many stones, and that she had converted from calcium oxalate to brushite and apatite, I added a very low dose of a long acting (23 hour 1/2 life) thiazide – chlorthalidone, 12.5 mg every other day – and achieved a reasonable result.

How, you might ask, did I get her sodium intake down and her urine flow up steadily yet she remain an operating room nurse? I talked to her about how she and her husband worked out their schedules and realized there was no time in the week for anything like cooking. So, I recommended they shop and do batch cooking on the weekends, freeze meals in proper sized containers, and use them for lunches and suppers. As for her water, I worked out her rotating in and out of scrub with several colleagues, which permitted fluids. She has been free of new stones for several years.

The manuscript score is said – on the web – to be an original by Bach. Perhaps a few of you who play classical keyboard music will have recognized the opening of the first fugue in d minor from ‘Art of Fugue’, his vast unfinished masterpiece. Bach is an immortal genius, and we are common folk, but the principle holds. He was a maker, as we are. Perhaps so much greater a maker that the comparison seems ridiculous, but I disagree. We make treatments out of the materials at hand and with what skills we can achieve. If we believe, as does the spiritus mundi of the West, that even one individual life is priceless, then what we do is, in its way, considerable under heaven. And, I might say, worth even my extravagances of time in the doing of it.

When I work

I see patients only one half day a week, because as a professor I do research which takes a lot of time and for which research grants provide support. Likewise, the writing of books, chapters, reviews, and papers takes up a lot of life. My meager clinical life is not odd for a university research profession; many I know do what I do. It is in fact the very smallness of the actual clinical time which permits me to be so specialized, and to have leisure to review what has happened to the patients I have seen so that past mistakes need not be repeated for a lifetime. My Google page is public; if you follow the link, and look, many of my papers have described what I have seen, and in the making of them I have made and remade the way I work with patients.

How I get paid

The only way that works is to bill by time. I keep track of how long I spend, and the university bills for that time. The documentation of the medical record for various levels of care is a distraction to me, and utterly unfit to what I do. What good is a stock review of systems, as an example, to someone who is after extreme details concerning the whole health and behavior of a patient? The basic assumption of my practice is that other doctors provide the broad range of care and have sent their patient to me for one special thing. I tell all patients about my specificity and the need to have proper primary care; to my knowledge they all do.

How I report

The computer formatted record is useless to me. I need to produce a consultant’s report, and do it in a way patients like and I find very effective. I use a blank report form in the EMR and share the screen with the patient by turning it at an angle where we both can see it. I tell patients we will write the record together and to correct any errors as we go along. I use up about a full single spaced page and when they leave patients get the report to take with them. We mail it out with all labs alter on to the physicians, and the patient. Incidentally, I have sent all my patients their entire record since I began in 1969, and have never encountered a single problem in doing it.

Something for later on

I haven’t told you everything. Nor can I. But I can bring some cases, as time goes on, and hope they show what I cannot tell. You might offer some, too. I am happy to have guests post a case. Let me know.

Bach was a teacher, incidentally. He wrote the 48 preludes and fugues partly for his gifted children to learn from. I believe the violin and cello suites, French and English suites, even the Musical Offering – though presumably made for Frederick II of Prussia – were also by way of education, perhaps his own. As for Art of Fugue why write 17 fugues in d minor on one theme if not by way of illustration; they make their way through every kind of fugal technique, and culminate in an unfinished fugue of such complexity no one has ever been able to fashion a reasonable ending for it.

Fredric L Coe MD

Return to Walking Tour on Supersaturation




  1. Judy C

    Dear Dr. Coe,
    I had been a stone former for over 30 years but only having stones every two or three years. However, stone formation increased significantly in late 2013-2016. I contacted you over a year ago (Jan 2016). At that time I provided you (online) with my lab tests, CT scans and KUB, and medication list, and you provided recommendations. I also had some concerns regarding my own MDs, procedures to remove stones, and lack of dietary education. I had already had a PNL that had complications…adm 9 days, two ureteroscopies, and two lithotripsies all since 2013. After having four stones from Jan to April of 2016, I started on your low oxalate diet in mid-April 2016. I used the Harvard list on this website to avoid all foods with very high and high levels of oxalate six days of the week plus also paired foods with calcium to those with oxalate. I did not drink anymore fluids that I had been drinking. I am very happy to report that I have not had any kidney stone attacks this past 12 months! Also, I have had wnl lab work plus a recent KUB shows no new formation of kidney stones! Although I still have fragments/dust/particles from a lithotripsy the area has not grown or moved. This is the first time since 2013 that I have not had any kidney stones! It now appears that my healthy eating diet (2013) in which I lost 25 pounds and exercised more both contributed to my significant increase in kidney stones. My nephrologist agreed that I no longer need to be on HCTZ or K Citrate as I taken myself off of it after 9 months after having normal lab work and KUB at 6 months. Thank you so much for all your help and for this wonderful educational interactive website. I have no doubt that you and you alone were responsible for preventing new kidney stone formation this past 12 months. I am now trying to determine how to lose weight and still have a low oxalate diet. I am very excited that I can now travel without worrying about having a kidney stone attack. Again, thank you so much.


    Judy C of St. Louis, MO

  2. Stavros Michailidis

    Good day Dr. Coe,
    Like the patient you describe in your article, I first presented with my stones in early adulthood. I had my first stone in my twenties and have been producing them ever since. My father had one stone at 25 and never presented again. Now, as a father of two I find myself wondering if my children will one day suffer from stones as well. To that effect, I have 2 questions.
    1) Why is it common for first time stones to occur between the ages of 20 & 30?
    2) What should I do if anything for my children?

    Thank you very much and warm regards,

  3. jon Adie

    I have had Oxalate stones since I was born – I use many strategies to control the production of.. and the pain of course when

    • Fredric Coe, MD

      Hi Jon, So long a time of calcium oxalate stones makes me wonder why. I hope you have had 24 hour urine studies with especial care for the urine oxalate level – primary hyperoxaluria can be like that. Be sure. Regards, Fred Coe

  4. shams zia

    Dr. Coe, my name is Shams Zia and I’m a nephrologist. I have started a kidney stone center along with the urologists and dietician in our program. As expected, our major population has calcium oxalate stones and NC is a known stone belt. I wanted to ask if you generally use urine pH sticks for home use on patients with hypocitraturia and low urinary pH to maintain a urinary pH of 6-7. I’ve a couple of patients who have been using these and several of them are interested to use them now. Thanks in advance.

    • Fredric Coe, MD

      Hi Dr Zia, I do not use them. To me overall 24 hour urine pH will more or less determine overall uric acid crystal formation over the day, and it is for uric acid stones we raise urine pH. As an example, suppose urine pH rises after eating – as it may – and some uric acid dissolves. But later on the pH dips and more crystals form. As for low urine citrate, urine pH is misleading in my observations. For example in RTA urine pH can be very high and citrate below detectable. Plots of urine citrate vs. urine pH taken in the CRC hour by hour show only a weak correlation. So, I think it is more stable to just measure 24 hour urine pH and citrate to monitor treatment. Regards, Fred Coe

      • shams zia

        Thank you so much Dr. Coe, this really helps. I may have more questions for you in future.

  5. Rumah Taman

    many plants extract use to treat kidnet stone. Is it safe and effetive enough?

    • Fredric Coe, MD

      Hi Rumah, I know plants have been mentioned but I also know we have inadequate studies so far for me to recommend any. Regards, Fred Coe

  6. Laurel Jenner

    I have been a patient of Dr. Coe’s clinic for many years. Initially, I saw Dr. John Asplin. He learned from the best. Everything Dr. Coe has written about working with patients, Dr. Asplin did, too. I was quite impressed at my initial and follow-up visits. Eventually, Dr. Asplin left to spend his time at Litholink, providing us a great service with 24 hour urine analysis. Dr. Anna Zisman took over, another terrific kidney stone specialist. As the clinic is a 2 hour one way commute, I see a local nephrologist and a urologist annually. Along with Litholink’s 24 hour urine testing, I get an annual CT Scan. I’m always afraid to go on vacation without knowing size and location of stones. This works for me. The high dose of radiation is worth it for my peace of mind. I go to Dr. Coe’s clinic every 3 years or so. Thankfully, my nephrologist (Dr. Donald Cronin) has great respect for Dr. Coe and follows his guidelines.

    Drinking upwards of 3 liters a day can be quite daunting early on. It becomes easier and 2nd nature within weeks. Adding fresh lemon juice to the water helps to keep citrates in a healthy range for kidney stone patients.

    I highly recommend any patient reading Dr. Coe’s blog entries, take this information to his/her own Nephrologist or Urologist. Prevention is certainly key!

    I have considered trying to form kidney stone patient support groups in the Chicago metropolitan area. It would be a beneficial service, with Urologists and Nephrologists referring their patients to the program. I believe a quarterly gathering and an online forum would be sufficient. The involvement of a Nutritionist or Dietician, educated about the different stone type dietary guidelines, would be important. This would have been very beneficial to me in the late 1990’s when I began the struggle with stones too large to pass. At that time, my local Urologist handed me a short 1/2 page dietary restriction, based more on oxylate stones, when unknown to him, my stones were phosphate. Thankfully, the internet was growing and I found Dr. Coe’s clinic.

    Here’s to no stones to large to pass and continued research identifying metabolic reasons for this disease – Cheers!

  7. Michael Williams

    Dr. Coe,

    I apologize if this topic is discussed in another section of your website., but I wonder if you could tell me what you have heard about Phyllanthus Niruri, or point me to the area where this is discussed. This plant, also called Chanca Piedra, has been touted as an aid in preventing or resolving kidney stones, but this could just be a marketing ploy to sell herbal cures that are worthless, and maybe even dangerous. I am intrigued, though, by articles mentioned on the National Institutes of Health website as to its potential. Thank you!

    • Fredric Coe, MD

      Hi Michael, I do not know about this plant but I’ll tell you what. Send along the link and I will read it and say what I can about the article from NIH. If it is interesting I will write an article about it and credit you for putting me on to it. Regards, Fred Coe

  8. Stephen Knohl

    Dr. Coe,

    Can you please comment on how urine volumes affect the reported measures of substances on 24 hour studies? As substances such as calcium, oxalate, phosphate, uric acid etc. can cyrstallize and come out of solution if there isn’t enough water to keep them at or below their solubility product, how, for example, can we be sure that a patient does not have hypercalciuria when a 24 hour urine study reports out, say, 120mg of calcium, with only 1 liter of urine (as the lab can only report what is dissolved in solution, it will not be able to report any calcium that has come out of solution with an accompanying anion)? I have anecdotally found a direct correlation between certain substances in the urine (such as calcium, phosphorus, oxalate, and uric acid) and urine volumes (to a point) and believe that low urine volumes may reduce the specificity/predictive value of 24 hour urine studies to predict abnormally high values of certain substances in the urine. I appreciate your thoughts on this. Thank you.

    • Fredric Coe, MD

      Hi Steve, and thanks for the great question. It is true that as urine volume falls supersaturations rise steeply and in vitro crystallizations are not rare. I have often found 24 hour urine uric acid excretions of 300 mg/day in adult men with scanty and acidic urine which rises to 900 mg/day when I raise pH or volume or both. Likewise, I have observed urine calcium excretion rise in high pH CaP stone formers when the volume goes up. As a lab practice we can acidify an aliquot of urine to dissolve CaP crystals and raise the pH to dissolve uric acid, and that can help. But if you do not have the 24 hour urine container a lot can be lost in it unless patients rotate it about so aliquots sent to central labs have some of the crystals. Put simply when I find low volumes I raise them and always recheck everything on the higher volumes to be sure nothing is missed. For uric acid excretion and SS in acidic urines, I have no confidence until pH goes up and volume, too. Warm Regards, Fred


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