Saturday, April 26, 2014

Social Media posed to disrupt medical education.

Read this post in the BMJ.
Now read this post by John Mandrola

When I grow up I want to be Dr. John Mandrola. Great blog post on the emerging preeminence of social media in medical education.
Perhaps the most notable facet of this new brand of knowledge transfer is its democracy. There are no paywalls; patients get access too. Let’s emphasize the value of patients learning alongside caregivers. This democracy of knowledge is vital. 
My favorite part of the post was his answer to the question of quality of information:

An often cited challenge comes in the vetting of information. Skeptics of social media and the Internet have asked me how one knows the truth. Their bias, of course, is that prose written in peer-reviewed journals is accurate and free of conflict. That’s a laughable bias these days.
His link was a personal experience but he could just as easily linked to Retraction Watch to make the same point.

Make sure you follow his link to the global emergency medicine journal club. Impressive work. A great model for #NephJC to aspire to.

By the way is live, if not a bit rough.

Thursday, April 24, 2014

#NephJC is coming

Next Tuesday will be the inaugural NephJC, a twitter journal club for nephrology. At 9pm Eastern there will be a twitter discussion on the article: Educational programs improve the preparation for dialysis and survival of patients with chronic kidney disease by Tamura et al. You can read about it here.

Tweet chats change the communication model of twitter. In the standard model of twitter interaction you see the tweets of the people you follow and your tweets are seen by the people who follow you. In a twitter chat you want to see all of the tweets surrounding a single hashtag, in this case #NephJC. This can be done by clicking on the hashtag, but this would require repeated clicks on the hashtag to keep it updated. Additionally you need to remember to addend each tweet with the same hashtag so other participants can see your comments.

Pressing the #icanhazpdf hashtag will find all of the tweets with that tag regardless if you follow the author.
TweetChat is a web app that makes it easy get the up-to-the-minute tweet stream of a certain hashtag, it also filters out all of the other tweets from your timeline so you can focus on the discussion at hand.

Go to and click Sign In the upper right corner.
 Authorize TweetChat
 Enter the hashtag NephJC and press GO
There is a custom tweet stream containing all the tweets across the twitterverse that are tagged #NephJC.

Additionally any tweet you enter in the tweet box will have #NephJC automatically added to it.

An alternative WebApp is Here is webcast on how to use it;

New Dietary Supplement Story: OxyElitePro

I learned about this at Forbes. But I guess I should have learned about it in the NEJM.

from this piece at Huffington Post
A popular diet supplement has caused an outbreak of severe liver disease, sickening nearly 100 people in 16 states since it was first reported in Hawaii last year, according to a new paper. The publication calls for a better system to remove dangerous supplements from the market.
Final score in the aegeline scare:
  • 97 cases
  • 47 hospitalizations
  • 3 liver transplants
  • and 1 death

And from the Department of This is Too Crazy to be Fiction:

I'm going to need to explore this paragraph in a few slides when I give my next talk:
And the agency has its work cut out for it: potentially dangerous supplements are widely available. More than 500 supplements have already been found to be adulterated with pharmaceuticals or pharmaceutical analogues, including new stimulants, novel anabolic steroids, unapproved antidepressants, banned weight-loss medications, and untested sildenafil analogues. In 2013 alone, researchers discovered two new stimulants in widely marketed supplements. My colleagues and I identified a new analogue of methamphetamine, N,α-diethyl-phenylethylamine (N,α-DEPEA), in a popular sports supplement. 3 FDA scientists discovered another stimulant, β-methylphenethylamine (β-MePEA) — a novel analogue of amphetamine — in nine supplements. 4 N,α-DEPEA and β-MePEA have never been studied in humans, and their adverse effects are entirely unknown; yet they are sold as “natural” products without having undergone any premarketing testing for safety. (Although supplements containing N,α-DEPEA were voluntarily withdrawn from the market, supplements containing β-MePEA remain widely available.) 

Tuesday, April 22, 2014

Electrolyte Review

For my final lecture at Providence this academic year I did an ABG review covering all of the core concepts regarding the rapid interpretation ABGs and a touch on hyponatremia.

Keynote       PDF

My two favorite slides were the slides that asked the residents to name the most likely diagnosis for a scenario with hyponatremia and various clinical settings:

Can you name all of them? I'll post my answers in the comments.

Thursday, April 17, 2014

Monday, April 14, 2014

Passover is Here Again! Updated with a working link.

Newest version of my Passover Haggadot, now for iPad!

For the link to work you will first need to install iBooks.

Friday, April 4, 2014

#NephMadness, choices we made.

After next Tuesday, all that will be left
will be to send out the prizes.
NephMadness announces the finals today and the winner next Tuesday. As the field has contracted we have been feeling the pressure. People we respect have questioned our choices. Some have pointed to our final four, JNC8 and Acute PD in particular, and had some negative thoughts abut their importance.

I’m sorry they are disappointed with the final four. I personally am more concerned with the elite eight* than the final four, as the elite eight represents the champions of each region. The elite eight were:

  • Toxins: Aristolochic acid
  • Renal replacement therapy: Urgent PD
  • Hypertension: JNC8
  • Regeneration: pericytes
  • Acute kidney injury: Balanced fluids
  • Electrolytes: Bicarb in CKD

  • Stones: Acute Medical Care
  • Biologics: belatacept
* Any one else feel that the Final Four and the Sweet Sixteen, make it feel that eight should be an alliteration? But the sad reality is, elite and eight are not alliterative. I prefer Great Eight.

Looking over this list I am comfortable and enthusiastic about each choice (except for pericytes which I still don’t understand but Matt and I didn’t want a dream, bioartifical kidney, to win. When they can keep that Frankenstein Kidney alive for more than a few days without clotting we'll reconsider).


JNC8 is the most important issue in hypertension because it is leading a massive sea change in the blood pressure standards of hypertension around the world. JNC8 is largely in agreement with all of the national guidelines that have been published world wide.

For one, the start-treatment threshold of >150/90 mm Hg applies to patients 80 years or older in the ASH/ISH guidelines, as opposed to 60 years or older in JNC 8.
AHA/ACC/CDC joins JN8 in not calling for stricter, lower, blood pressure targets in the presence of CKD, diabetes, or proteinuria.

JNC 8 versus KDIGO

Everywhere hypertension experts have been reconsidering previous aggressive blood pressure targets. In the end, the blood pressure targets of JN8 are not based on firm data that fit every clinical scenario and we may end up revising them in the face of future data but these guidelines will determine the future of stroke, coronary disease, heart failure and kidney failure for millions of people being treated for hypertension.

Additionally, JNC8 and the ACC/AHA cholesterol guidelines together usher in a new era where observational data is no longer considered acceptable data to base guidelines. This resulted in a relaxation in both cholesterol and blood pressure targets. This is a sea change in how guidelines are developed. This is important. JNC8 also grades the evidence. E level evidence, i.e. expert opinion, on such a fundamental question as systolic blood pressure target, should be humiliating to the hypertension community. I believe that letter grade will stimulate the community to find the answers definitively. I salute the guideline writers for having the courage to admit that the emperor wears no clothes.

Urgent PD

Urgent PD triumphed in the renal replacement therapy region. We chose this because it is the first innovation in peritoneal dialysis in the last 20 years that seems capable of moving the needle and reversing the trend of dwindling number of patients on home therapy.

Two years ago there were one or two programs in the country, today there are over 100 urgen PD programs. PD, according USRDS is $20,000 a year cheaper to administer than HD and considering that 115,000 people initiate dialysis every year the savings quickly exceed my ability to track the zeros (9, I think). No one knows if PD is better than HD, and it probably is roughly equivalent, but it is definitely cheaper. Urgent PD is an innovation that shows promise in increasing the numbers of people in PD. After starting an urgent PD program we doubled our PD population after years of decline. When I mentioned that story to others who had urgent start PD programs they nodded their head and say the same was happening at their centers.

NephMadness Decisions

We did not make our decisions without thought and it is inevitable that others will have different values when it comes to these ambiguous and irrational comparisons. I am comfortable with the decisions that we made and do not feel we are limping to the finish line.

Tuesday, April 1, 2014

#Nephmadness Explanations: Serum Anion Gap

The fall of the serum anion gap.
The serum anion gap was an entry on the electrolyte region of NephMadness. It won it's opening round over urine anion gap and advanced to the Sweet 16 by beating hypertonic saline but failed to win the electrolyte region when it fell to Bicarbonate in CKD.

CJASN did a recent review of the anion gap and they were frank with its limitations:

Some interesting notes about the anion gap: though the serum potassium was included in the original derivation of the calculation, none of the major U.S. textbooks include it. The upper limit of normal anion gap from the 8 sources included in the paper is much higher than I teach. I use 12 and after the ASN Board Review Class, I remember feeling that was too high.

The article then discusses the fact that ion selective electrodes are more sensitive for chloride so they detect higher chloride concentrations so that average and pathologic anion gaps are lower.

The article discusses the importance of albumin in the normal anion gap. As albumin falls, either the limit for a pathologically elevated anion gap needs to fall or the calculated anion gap needs to be adjusted upwards. The article recommends the latter. The anion gap should rise 2.5 for ever 1 g/dL the albumin falls below normal (presumably 4 g/dL). The authors recommend that albumin adjustments be incorporated into laboratory reporting so clinicians do not need to worry about this.
The meat of the article is contained in table 3 where the authors review 5 studies that looked at the sensitivity of an increased anion gap for lactic acidosis. It's not a pretty picture.

The anion gap is meant to be a screening test, if it is positive the specific cause of the increased anion gap can be investigated with specific assays. Screening tests are supposed to be sensitive so that if they are negative one can rule out that potential diagnosis. Here we see that the anion gap is wearing no clothes. Sensitivity can be as bad as 43%, but typically runs around 60-70%.

In Adams et. al's (PDF) analysis of emergency department patients, 50% of patents with a lactate level between 5 and 9.9 had an anion gap below 12!

The authors theorize that the anion gap fails due to the broad range of normal in the anion gap. The normal anion gap can range from 3 to 12, so suppose a patient is sitting at the low range of normal say 3 or 4, they could absorb an lactate level up to 8 or 9 mmol/L while still maintaining a normal anion gap. See the illustrations with Gamblegrams below:

Both James and Jean Luc start with normal anion gaps, though James is at the upper limit and Jean Luc is at the lower limit of normal.

Both patients develop equivalent and significant lactic acidosis but only James develops an anion gap
The article then describes some unusual behaviors of the anion gap. The first is that the anion gap can rise more than the bicarbonate falls. A basic tenet of the anion gap is that the ratio of the change of bicarb and the anion gap is 1:1, this is the theory that the delta gap equation rests on. In lactic acidosis apparently the the anion gap can rise 1.8 for every fall in the bicarbonate of one. The net result of this is patients can have significant lactic acidosis in the presence of a normal serum bicarbonate.

Additionally, patients with identified organic acidosis, the identified acid typically does not explain the entire gap. 

The authors discuss some data on using personalized normal anion gap targets from previous labs. This would help the sensitivity of the test in patients who run low normal anion gaps and have a hard time cross the threshold for an increased anion gap (see Jean Luc above). However, the authors point to a study (Lipnick et al. 2013) which used this technique and still missed approximately 30% of lactic acidosis cases.

This is a good article but it does not address issues such as the the anion gap's usefulness in the diagnosis of the toxic alcohols and its use in the management of DKA.

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