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Saltiest Sodium. Dumbest Dude.

My work-shop on sodium includes a bit on all the cases of hyponatremia due to fraternity hazing.

I also include the crazy case of Jennifer Strange.

But I had never heard of idiot induced hypernatremia until this case report:

A nineteen year old male drank a quart sized bottle of soy sauce on a bet.

Two hours later he was brought to the ER comatose and seizing. His sodium was 177. They initiated hypotonic fluids and arranged transfer to a tertiary care center. At the tertiary care center the sodium was still higher at 191. The doctors then changed the fluids to D5W at 12,000 mL per hour. They gave 6 liters of D5W in 30 minutes.

After the infusion he opened his eyes and regained spontaneous movement. He was discharged on hospital day four neurologically intact with only some minor abnormalities on the head MRI, all attributed to postictal changes.

How high is a sodium of 191? MedCalc will not even accept it as a possible sodium concentration:

A couple items of note:

  • The infusion of D5W raised his serum glucose from 365 (hyperglycemia causes insulin resistance) to 1,116 mg/dL.
  • The authors do not comment on what access they used to infuse D5W at a liter every five minutes.
  • In addition to the hyperglycemia, the D5W infusion dropped the potassium from 5.1 to 2.5 in 30 minutes! That is kind of terrifying.
  • The authors use the Katz correction for hyperglycemia, (eat it Hillier).
  • The authors do not discuss how they decided on 6 liters of D5W. Full correction down to 140 would by roughly 12 liters, so perhaps they decided on 12 liters in an hour with continuous neurologic assessment and when he began to have spontaneous motor movement after 30 minutes they slowed down.

Some nerdery about the sodium exposure: He drank a quart of soy sauce. A quart is 946 mL. The article states that soy sauce is 17-18% sodium chloride. Here are some meta calculations, in case you are interested:

Read the article, it’s a good read and it has the highest urinary sodium I have ever seen, 270 mmol/L (almost twice as salty as normal saline). They discuss other extreme hypernatremic conditions, and theories on rapid or slow correction.

Slides for Keynote | PDF

Update from Twitter:

@kidney_boy I would guess they used a pressure bag or infuser (e.g. Trauma 1) to get in a L every 5 min
— Seth Trueger (@MDaware) June 10, 2013

@mdaware @kidney_boyA good 14 ga 1.75 inch peripheral IV can do 333 cc/min with a 1 meter pressure head to gravity.
— philroman (@philroman) June 11, 2013

@kidney_boy I’ve seen 216 before. Started at 196, rose more with initial NS administration. Kid with ichthyosis, and bad dehydration.
— Ken Tegtmeyer (@pccm_doc) June 11, 2013

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July first approacheth

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.

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Medicine, 4 log units above normal!

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

Still can’t believe I didn’t get a picture of the urine on the first day, it was black.

.@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:

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Best post I have read on how to pay donors for kidneys

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.

Rohin Dhar, at the Priceonomics Blog has put together a brilliant, straight-forward essay describing the problem, showing how current ideas for increasing the organ supply (make donating organs the default after death, paired kidney donation, improved donor-recipient matching) are not working and cannot hope to solve the problem and then goes on to describe a hypothetical organ purchasing system run by medicare. I’m convinced.
When discussing this on twitter, the always interesting Christos Argyropoulos talked a bit about the problem with Greece’s implementation of default organ donation:

@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

An open access review of Iran’s transplant system can be found here (A non-systemic review from McGuil University? I grow feint.) Here is the Kidney International paper Dr. Argyropoulos was referring to.
Look at how the number of transplantations is growing in Iran:
Mitra Mahdavi-Mazdeh. Kidney International, 2012
While it is flat in the US:

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.

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And therefore never send to know for whom the bell tolls; It tolls for the TTKG

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

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Hey Hey it’s your birthday!

Five years.
584 posts.
545,000 pageviews.

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:

Looking at the data you can see how ordinary PBFluids is. The average number of posts is weirdly average, there are a number of blogs with more posts (I fully expect to be passed by the Kidney Doctor in his next bolus of productivity). It is only remarkable in that it is the third oldest active blog, behind the Renal Tsar and RFN.

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.

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App.GoSoapBox.com. Three times a charm.

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.

Non-anion gap metabolic acidosis (Powerpoint, PDF)

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.

I started the lecture with a couple of slides walking them through logging in and getting familiar with the system.
Then I had them do a pre-test to assess what their baseline knowledge of the subject was
Then I posted an ABG and asked them to interpret it.

Use of Winter’s Formula

I had a series of questions on the proper use of the urinary anion gap.

And the lecture finished with a series of quick case vignettes designed to test knowledge of NAGMA.

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.

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The Road to NephMadness

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.

If you ever wanted to know what the traffic at PBFluids looks like?
Ever wonder how many copies of the Fluids book are out there?
Ever wonder what the hell the Microbiology Companion is?
All of these secrets and more are revealed in the presentation.