musings of a salt whisperer
I wrote a post for the Pediatric Career blog. It is about July first, the most significant date in the academic medicine calendar. I did not discuss patient risk or medical mistakes. I have blogged about those before. I discussed how to leverage this new beginning to develop a fulfilling and productive career in medicine. Read it.
Highest CPK I have ever seen:
That is the first CPK over one million I have seen. I love how the CPK of 4,000 on day one, you know the CPK that is 20x the upper limit of normal, is not high enough to even be rendered on the graph. For the scientific-minded here is the same data on a log rhythmic scale:
We were able to successfully alkalinize the urine (EBM purists can bite me, I believe the bench data here) and she never became oliguric, however on day three her potassium was 7 and we initiated dialysis. Surprisingly, phosphorous never got out of control.
She also had the highest CRP I have ever seen, 147.
The etiology you ask? She presented three days after a sore throat. We initially discounted viral rhabdo because the CPKs were so high but the Coxsackie B type 3 and 4 antibodies were off the scale and the literature is sprinkled with similar case reports (here and here). Muscle biopsy results are pending.
Muddy brown cast (day one, unspun specimen):
Urine sample (day two with urine pH of 8.5), no red cell on U/A
.@kidney_boy re:CPK I see Phos was never uncontrolled – anything to say about Ca both at presentation & during alkalinisation? #nephrology
— Tom Oates (@toates_19) June 4, 2013
See this:
If you want to start a fight among nephrologists, start talking about paying donors for their kidneys. This may be the most contentious issue in nephrology. I personally am a believer in the concept but trying to imagine a free market for organs makes me nauseous.
@kidney_boy The Iranian system was covered last year in KI if I am not mistaken. Opt out can also backfire as it has in Greece
— ChristosArgyropoulos (@ChristosArgyrop) May 29, 2013
@kidney_boy Opt out legislated in 2011;hugely unpopular, a couple of high profile resignations from the Ntl Transplant body-> # of Txps down
— ChristosArgyropoulos (@ChristosArgyrop) May 29, 2013
@kidney_boy Public pushback makes ICUs reluctant to refer donors,even though almost everyone is. Opt out systems are embraced not imposed
— ChristosArgyropoulos (@ChristosArgyrop) May 29, 2013
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| Mitra Mahdavi-Mazdeh. Kidney International, 2012 |
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| USRDS |
The current system of paired exchanges and campaigns for kidney donors has noble intentions, but it’s not working. People are needlessly dying as a result.
I was never a big fan of the trans-tubular potassium gradient. I taught it because it was expected core knowledge for medicine residents. While I thought it was a poor test to assist in clinical management I delighted in using it to teach physiology. Understanding how the TTKG works, why it works and the thinking behind the exclusion criteria required sophisticated understanding of potassium and solute handling in the distal nephron.
My primary complaint of the TTKG was how useless it was in the assessment of hyperkalemia. In persistent hyperkalemia the TTKG is always inappropriately low (except in cases of rhabdomyolysis or tumor lysis syndrome where it is possible to get persistent hyperkalemia despite normal renal potassium handling, woe to the patient, whose doctor is relying on the TTKG to diagnose rhabdo). The TTKG was not useful for differentiating the various elements of renal potassium handling that can go off the rails to cause hyperkalemia.
The TTKG could do a neat job of differentiating renal from extra-renal potassium losses in hypokalemia.
Then in 2011 this article came out which showed urea cycling to occur in the late cortical collecting duct. The authors believed that urea delivery to the cortical collecting duct was an important driver of potassium secretion. This broke one of the central assumptions of the TTKG: that no appreciable solute resorption occurs in the medullary collecting duct, the only reason the osmolality increases is the absorption of water.
It looks like the editors of UpToDate have voted the TTKG off the island, here is what UpToDate has to say about the TTKG. In Evaluation of the patient with hypokalemia:
Trans-tubular potassium concentration gradient — The transtubular potassium concentration gradient (TTKG) has been primarily used in the evaluation of patients with hyperkalemia. However, we do not recommend using the TTKG. Details pertaining to the TTKG and the reasons for our recommendation not to use it in hyperkalemia are discussed in detail elsewhere. (See “Causes and evaluation of hyperkalemia in adults”, section on ‘Transtubular potassium gradient’.)
In Causes and evaluation of hyperkalemia in adults
Trans-tubular potassium gradient — It would be desirable to assess the degree of aldosterone activity in patients with hyperkalemia by estimating the tubular fluid potassium concentration at the most distal site of potassium secretion in the cortical collecting tubule. Although this measurement cannot be made in humans, it was proposed that the potassium concentration at this site could be estimated clinically from calculation of the transtubular potassium gradient (TTKG) [91-93].
However, in a later publication, the authors of the original studies found that the assumptions underlying the TTKG were not valid [94]. It was concluded that the TTKG was not a reliable test for the diagnosis of hyperkalemia. We recommend not using the TTKG to evaluate patients with hyperkalemia.
RIP TTKG
Five years.
584 posts.
545,000 pageviews.
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| Monthly page views. (The posts from 2007 are back dated pages written at a later time that I use for my schedule and some other projects, first true post was May 30, 2008. Work arounds for dealing with the limits of Blogger) |
The first peak is my review of medical calculators for the iPhone.
The second peak is the Margaret Atwood Super Hero Costume experience.
The most recent surge looks less like a peak and hopefully a new plateau, I don’t know the reason but it may have something to do with Google rolling out Penguin 2.0. Decreased search results for spam presumably mean more research results from high quality content.
I asked for a list of nephrology blogs last week and I know have what I believe is a comprehensive list of nephrology blogs oriented to medical professionals. There are dozens (hundreds?) of patient blogs and I did not include those unless they included significant scientific and or nephro-medico-politico content (see Hemo-Doc and Dialysis from the sharp end of the needle). I have found 30 blogs:
I also asked you to vote for your favorite post (here and here). We have a winner:
Other honorable mentions:
The blog has been a total gas and I really appreciate all the readers and their feedback. Five years down and I still have plenty of steam. I look forward to celebrating the blog bar mitzvah in 2021.
Please take a moment to vote for your favorite post on PBFluids.
I have been trying to use GoSoapBox to add some interactivity to my lectures. My first attempt did not work out at all like I wanted it. I used quizzes instead of polls. Then I added GoSoapBox elements to my non-anion gap lecture and I tried to use it at McClaren Macomb a couple of weeks ago. McClaren built this beautiful auditorium under the hospital. It is state-of-the-art in every way except it has no way to plug in your laptop. My Kingdom for a free VGA cable. So I had to run the lecture off Dropbox on the Window’s machine they had available. Not surprisingly it looked like ass. Then, when I tried to use GoSoapBox, I found that the auditorium had no cell signal penetration (basement) and no wifi (whiskey-tango-foxtrot). Who builds a modern auditorium like that? Total Fail.
On Tuesday I gave the same lecture to the Internal Medicine Residents at Providence. This time the system worked great.
As the residents were getting food I was joking with a few them and we were stuck on what Batman’s father’s name was. The residents found the Social Q&A section and used it to provide the answer.
The feedback on the system I received from the residents was excellent. They loved it. I made a mistake of using my laptop to both run the presentation and manage GoSoapBox. GoSoapBox requires the presenter to open the polls at the appropriate time so students can’t see the poll until the appropriate time. Powerpoint got cranky when I would bounce to my web bowser and then back. Next time I will manage GoSoapBox on my iPad.
Disclaimer: I was given a free 6 month trial of this product. I have received no additional payment or inducement for promotion. I was looking for a system like this and Gary Abud, a friend and Michigan Teacher of the Year, suggested I give this a try. He arranged the free trial.
I know I said I would stop talking about NephMadness, but I just got a headset in order to record screen casts and I wanted to try this out. This is my first Screencast, as delivered at Beaumont’s MedEd Week.
Here are posts tagged kidney.
I’m trying to generate a master list of renal blogs. I a m looking for blogs that would be of interest to nephrologists, doctors and medical students. I am not looking for patient blogs unless they have significant scientific information. See HemoDoc and Sharp End of the Needle as examples. I am also interested in blogs that are no longer being maintained or may have disappeared from the internet (see Utah Renal Fellows). I am limiting my analysis to English Language, sorry NephroHug.
Here is my list so far:
Update found another one:
20. Kidney Talk by Shalini Mundra published from Feb 2010 to March 2010.