Things that bug me – telling me normal (CBC, BMP)

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Category : Medical Rants

Dr. Rabih Geha’s excellent post on Closler – Every Piece of Data Matters – has stimulated much thought. He makes one important point that I would like to expand.

My mind finds it much harder to attach diagnostic significance to pertinent negatives. Even if their impact on a diagnostic hypothesis is equal, I find that a positive test result sways my reasoning more so than an equally impactful negative test.

My students and residents know that I want to hear the numbers. Sometimes normal is not normal. Sometimes seemingly normal gives clues.

The problem comes from our laboratory definition of normal.The lab uses large data sets to estimate a “normal” range. Sometimes the clinical condition says otherwise.

Several years ago I had a patient with an unknown “pneumonia” who was not improving. On examining his labs I noted that his creatinine has risen from 0.8 to 1.2. Both numbers were technically normal, but a 50% increase in creatinine should grab out attention. When we finally obtained a urinalysis, he had evidence of acute glomerulonephritis. The “pneumonia” was really GPA.

What is a normal platelet count? What is a normal WBC? How do we interpret a serum calcium if we do not know the serum albumin? What does it mean when the BUN is 2? What is the BUN/creatinine ratio – and does that help us understand the patient’s story?

The patient has a history of severe vomiting, but has a normal bicarbonate level. What is the anion gap? Does the computer flag an abnormal anion gap?

When students present, I expect to hear the numbers. When reading MKSAP questions or reading (or listening to) Human Diagnosis Project cases, too often labs are reported as normal. Yet the numbers may still provide some value.

So here is my call for presenting the numbers and let me decide if they provide information. Perhaps I can teach the team something from these labs. But let me decide if the numbers are actually normal. Please!

Mystery novels, cold cases and the diagnostic process

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Category : Medical Rants

Currently listening to David Baldacci – Redemption. The mystery novel, like many others, demonstrates important diagnostic principles.

The story is one of missed diagnosis – in the mystery the detective is asked to reopen a case. Once he reconsiders his first murder case (13 years later), he recognizes mistakes that he made. He carefully reanalyzes several pieces of evidence considering how they fit the original assumptions.

Once he decides that he needs to reinvestigate, he returns to the scenes of the crime. He re-examines the evidence; he once again interviews potential suspects; he focuses on inconsistencies.

In medicine we should do that regularly. When in doubt, return to the patient, retake the history and physical examination. Ask yourself, if the current diagnosis is wrong, what else could be the proper diagnosis.

When asked about another detective for whom he has low regard, he opines that the other detective is adequate but prone to focusing on the easiest explanation, and ignoring the inconsistencies.

This reminds me of an Agatha Christie quote:

“It often seems to me that’s all detective work is, wiping out your false starts and beginning again.”

“Yes, it is very true, that. And it is just what some people will not do. They conceive a certain theory, and everything has to fit into that theory. If one little fact will not fit it, they throw it aside. But it is always the facts that will not fit in that are significant.”
? Agatha Christie, Death on the Nile

We can learn much about diagnostic errors and the diagnostic process from mystery fiction. To do so requires that we relate the detective process to our own diagnostic process. This seems like a natural progression, since being an internist starts with detective work. Remember that many of your best diagnostic successes come on “cold cases”. As in this book, when a previous diagnosis does not make sense, consider reopening the diagnostic process as a “cold case”.

Podcasts for medical students on internal medicine

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Category : Medical Rants

Today, we received two 3rd year medical students starting their IM rotation. I told them I would give them a list of podcasts that should help them get oriented to internal medicine. This is my podcast v1.0 list:

From the Curbsiders:

142 Cirrhosis TIPS for Acute Complications

104: Renal tubular acidosis with Kidney Boy, Joel Topf MD

92: Pulmonary Embolism for the Internist

86: COPD: Diagnosis, treatment, PFTs, and nihilism

76: Pneumonia Pearls with Dr Robert Centor

61: Vasculitis and Giant-Cell Arteritis: ‘Rheum’ for improvement

52: Anemia: Tips, and tools for diagnosis and treatment

20: Hypertensive urgency and severe hypertension

From the Clinical Problem Solvers:

Hypokalemia

Hyponatremia

Abdominal Pain

Syncope

Hypercalcemia

From Core IM:

Stress Testing

Hepatic Encephalopathy

From Annals On Call:

C. Difficile

Diverticulitis

Diuretic Resistance

Each podcast above has many more excellent episodes. I picked these out on a first pass, quick suggestion for my new 3rd year students. Would appreciate suggestions for improving this list.

Lessons learned from the National Champions

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Category : Medical Rants

All physicians have failures. The best physicians learn from those failures. They become better physicians and work on continuous improvement.

Everyone who knows me well knows that I have had a 52 year obsession with UVa basketball. While I love all the sports teams, basketball is my true love. Better wordsmiths than me would have a difficult time explaining my joy in Monday night’s championship game. You can imagine my dark place after last year’s loss in the first round.

So what does this have to do with medicine. Maybe nothing, but we can learn important lessons from literature, music and sports. In this case I will likely stretch the lessons, but in my post game euphoria, please indulge me.

Lesson #1 – do not let a failure define you, rather let it motivate you. Focusing on diagnostic errors (which we all make), learn from those errors. Every diagnostic error happens for a reason, explore the reasons and own them. Perhaps you (like Virginia) will need to modify some procedures.

Lesson #2 – pay attention to the details. Virginia’s coach, Tony Bennett, stresses playing each possession without regard to future possessions. Stay in the moment, analyze where you are, without regard to what you were thinking yesterday. Has the patient gone down the path expected? Does the diagnosis still make sense.

Lesson #3 – do not be scared to change your approach. Learn from your mistakes and try not to repeat them.

Lesson #4 – embrace humility. We are never as good as we desire, nor as bad as we fear. Understand who you are, and work to better yourself, even if you really are pretty good. We can always improve. We can always learn something from others.

Lesson #5 – value everyone on the team. Nurses can make us better; clerks can make us better; the cleaning staff helps everyone. As an attending physician, I learn from the residents, interns and students. My first goal is to help everyone improve and to focus both on the patients and the learners. We learn from our patients. Minimize hierarchy and then everyone benefits.

I hope that I have provided some food for thought. I cannot describe my happiness with basketball today. But almost every day I have that same happiness with internal medicine. I continue to make mistakes, but do not fear them. We all try to minimize them, but when they occur we must learn from them for our own sake and more importantly for the next patient’s sake.

Fictional detectives as diagnostic models

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Category : Medical Rants

Like most internists, I love a good mystery novel, TV show or movie. Mention Sherlock Holmes and internists smile. When Dr. Mark Shapiro wanted to complement Dr. Gurpreet Dhaliwal for his diagnostic expertise, he labelled their podcast discussion – Gurpreet Dhaliwal, The Sherlock Holmes of Medicine

Studying fictional detectives helps me understand some basic principles of diagnostic excellence. A common trope in detective novels is the misdiagnosis. Someone has been falsely accused or even convicted of a heinous crime. Superficially, the evidence points to the accused, but the fictional detective has an uncomfortable feeling because of something in the case that does not fit.

In the BBC series, Sherlock, Season 1 Episode 2, Sherlock states, “You have a solution that you like, but you are choosing to ignore anything that you see that doesn’t comply with it.

It’s that uncomfortable feeling you get about a patient’s diagnosis. Many years ago I described this as reading the textbook description of the patient’s diagnosis and finding that it does not fit. When that happens, the patient is not wrong, rather you are reading on the wrong page.

When this happens, we need more data, or as Sherlock said in the Adventure of the Copper Beeches, “Data! Data! Data!” he cried impatiently. “I can’t make bricks without clay.

Sometimes the data comes from questioning the patient again. When stumped go back to the bedside. Or as Agatha Christie wrote for Hercule Poirot, “It often seems to me that’s all detective work is, wiping out your false starts and beginning again. Yes, it is very true, that. And it is just what some people will not do. They conceive a certain theory, and everything has to fit into that theory. If one little fact will not fit it, they throw it aside. But it is always the facts that will not fit in that are significant.” 

When the diagnosis does not make sense, start over. Michael Connelly’s great character Harry Bosch said, “I’ve learned over the years that sometimes if you ask the same question more than once you get different responses.” And this really happens at the bedside.

These wonderful, entertaining detectives give us permission to be skeptical of accusing a particular disease as the cause of the patient’s illness. We owe our patients a dispassionate, dogged approach to the truth of their diagnosis. We have great role models from whom we can all learn.

And remember the wisdom of Dashiell Hammett in the Thin Man, “The problem with putting two and two together is that sometimes you get four, and sometimes you get twenty-two.

Confusion after gastric bypass with Roux-en-Y

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Category : Medical Rants

At at recent case conference, we discussed a woman who had had a gastric bypass 20 years previously, and now had confusion. To remind you of the details of a gastric bypass:

First, a small stomach pouch, approximately one ounce or 30 milliliters in volume, is created by dividing the top of the stomach from the rest of the stomach. Next, the first portion of the small intestine is divided, and the bottom end of the divided small intestine is brought up and connected to the newly created small stomach pouch. The procedure is completed by connecting the top portion of the divided small intestine to the small intestine further down so that the stomach acids and digestive enzymes from the bypassed stomach and first portion of small intestine will eventually mix with the food.

I posed this question on twitter, but unfortunately did not give enough specification of the problem. Restated, a patient with progression confusion presents years after the procedure (very successful at weight loss) and no apparent infection.

Our leading differential included hyperammonemic encephalopathy, thiamine deficiency, B12 deficiency and d-Lactic acidosis.

We excluded d-Lactic acidosis become the symptoms were not episodic and the electrolyte panel did not have a moderately increased anion gap (usually around 18). A B12 level was normal, excluding that possibility.

The patient did have both hyperammonemia and thiamine deficiency. She also had several vitamin B deficiencies and low levels of copper, zinc and selenium.

After adequate replacement, her confusion eventually improved.

The problem of hyperammonemia is very dangerous. This paragraph from a recent article explains it well.

Patients presenting with hyperammonemic encephalopathy after Roux-en-Y gastric bypass surgery presented with overlapping clinical and laboratory findings. Common features included: (1) weight loss following successful Roux-en-Y gastric bypass for obesity; (2) hyperammonemic encephalopathy accompanied by elevated plasma glutamine levels; (3) absence of cirrhosis; (4) hypoalbuminemia; and (5) low plasma zinc levels. The mortality rate was 50%. Ninety-five percent of patients were women. 

Likely the zinc deficiency is a major culprit here. Studies of the ornithine  transcarbamylase cycle show that zinc is an important co-factor. Like to many patients with successful bypass surgery the patient presented was not taking supplementary vitamins with trace metals. Several companies make vitamins labeled as bariatric vitamins that have adequate trace metal supplementation.

The patient presented at our conference eventually did well after receiving supplementation that included zinc.

The role of podcasts in medical education

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Category : Medical Rants

Obviously I am very biased, hosting a podcast now for 8 months, and being a guest on two other popular podcasts – The Curbsiders and The Clinical Problem Solvers. Given my obvious COI, here are my thoughts on the contribution that podcasts are making for students, residents and practicing internists.

Two or three years ago some students asked me if there were any good podcasts to listen to while on their medicine clerkship. Soon thereafter, two things happened: The Curbsiders started their podcast and the Annals of Internal Medicine asked me to develop a podcast. I had a growing love of podcasts as an accompaniment on long drives. When the Curbsiders asked me to appear on episode #16 of their new podcast in October 2016, I jumped at the chance and started my love affair with medical podcasts.

Now when I make rounds for 1/2 months or full months, I regularly recommend podcasts to the learners. Now that we have released 16 episodes of Annals on Call, I frequently get comments from colleagues and learners about individual episodes. This week at an Update in Hospital Medicine done at our noon conference, podcast episodes were quoted. Earlier this year the CMRs asked me to give Grand Rounds on social media. The response from house-staff and faculty was outstanding.

Why so much excitement about podcasts? I think it follows from the classic way we learn. Storytelling is likely the oldest form of education. We learn best from stories. This concept holds particular in medical education. Patients are our best teachers. The best is taking the history ourselves and then following the process of diagnosis and teaching. Next best is learning from someone else telling us a compelling story about a patient.

I do not think we can overestimate the value of clinical stories to expand our medical diagnostic and therapeutic abilities. As a resident, I loved and tried to never miss Morning Report. I love hearing cases presented at a conference and discussed in depth. That knowledge sticks so much better than reading an article, unless the article helps me understand my patient.

In addition to the 2 podcasts above, I particularly love The Clinical Problem Solvers, because each week they provide a highly selected Morning Report case to solve. They focus on the thought process and schema for evaluating a problem (syncope, eosinophilia, chest pain, etc.).

Other IM podcasts that I frequent include Core IM and Bedside Rounds. I get different things from each podcast, but most of all I get continued learning. Even at age 70, I want to continue to learn more so that I can do a better job teaching and caring for patients.

Podcasts increase learning and (IMHO) the joy of medicine. As internists, we love solving our patients’ puzzles. We all want to be Sherlock Holmes. This gets us closer. And I love that our students and residents are enthusiastic devourers of this teaching.

The problem of admission diagnoses – a guest post

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Category : Medical Rants

I received this response to a recent post. It is so good that I wanted to share it – so with Dr. Thomas Nielson’s permission I have. He makes the important point that the rush to LABEL the patient with the diagnosis has major unintended negative consequences. He says it so well that I encourage your reading and comments.

Thank you for this post. This is a problem that occurs from time to time, and I believe that the current system in place for admissions is a large part of the problem.

We are asked to diagnose people in the emergency department because we need an “admission diagnosis” so that we can make sure that we meet “admission criteria”. The people in hospital administration who require this have never taken care of patients themselves, and they have no idea what they are talking about.

There is a disconnect between administrative types and doctors, and I do not know how this can be solved in our current system.

Example: Patient presents with AMS and is found to have a massive acid base disorder in the ED. What is the diagnosis? I have no idea! I need to admit the patient to the hospital and run a bunch of tests before I can tell you what the underlying problem is. Is it ethylene glycol poisoning? Is it their renal failure? I don’t know.

The current system puts the cart before the horse in requiring an admission diagnosis. What happens is some random diagnosis is given to the patient so that we can get them into the hospital. Unfortunately, because the system demands that we treat the patient with “quality” care, this diagnosis puts a process in place. Now the patient is run through a bunch of tests relating to the admission diagnosis which may or may not be the actual problem going on with the patient. And at the end the patient is sent home, dazed and confused, without a clear understanding of WTF just happened to them.

Think I am kidding? How about this example: Patient present with shortness of breath and the radiologist in the ER says pulmonary vascular congestion. The BNP is 300. Now the patient is admitted with “congestive heart failure”. Do we know it is CHF? NO! But now, because CHF is a diagnosis which beancounters believe they can treat by protocol alone, the patient is set upon a course in which all of the “quality” measures must be met to make sure that we get paid. The patient does not know what is going on, but all of a sudden they are being put on a low salt diet, being given an ACE inhibitor, and so on. They will (hopefully) get an echocardiogram and then….what happens if the echo is normal? SYSTEM FAILURE

To get back to your post, it is often the system that is running away with the patient when we have a sense that the diagnosis is wrong. And studies have repeatedly shown that pinning a diagnosis to a patient early in the process, which is required by the system, leads to significant bias in the doctor’s treatment process and judgment.

What we need in this country is for the doctors to reclaim their rightful place in the system. All of the quality metrics BS needs to go right out the door.

How do we do this? I am afraid that we are going to have to revert to doctor-run hospitals, with all cash. Let patients deal with their own insurance companies.

The danger of ignoring your instincts

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Category : Medical Rants

Recently we had a patient admitted for a diagnosis that did not really fit his problem representation. The diagnosis was a convenient one, and easily treated. He initially responded to treatment and we discharged him. The diagnosis assumption nagged at me, but I did not push forward with a test that my mind wanted.

A week later he returned (the dreaded readmission), with the same symptoms. The admitting resident expanded the treatment for the same diagnosis.

The next morning on seeing the patient we were even more uncomfortable than on the first admission.

As often happens, this is a story of community acquired pneumonia that was not CAP. We ordered a CT scan that clarified the abnormal Xrays. We reviewed the CXRs and CT with the radiologist. His symptoms never fit CAP. His CXR could have been CAP. Only the CT scan pointed us in the right direction.

I preach expanding the diagnostic evaluation when the problem representation and the illness script do no match. Yet, doing so is often difficult. Our patient’s diagnosis was delayed a week, with continued discomfort for that entire week.

So I am challenging myself. I “knew” that we did not have the right diagnosis, but “I did not pull the trigger”. I am not unusual. I suspect we all suffer from this error.

The second time I had no hesitation. How do I convince myself to honor my instincts in such patients?

I suspect you all have experienced similar situations. This story (and I have withheld some details for patient confidentiality) likely seems rather common to others.

I hope to do better the next time. Part of not doing better is refusing to rationalize what happened, but rather learn from the experience. The patient improved dramatically when we treated the right process.

My tweetorial collection

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Category : Medical Rants

You can probably tell that I tweet much more than I write blog posts these days. I have started doing tweetorials – linked collections of tweets that tell a story. Most tweetorials represent teaching or rather online chalk talks.

They are now being collected (along with other tweetorials that I particularly like and want to use. Here is the link: Medrants Tweetorials

If you do not follow me on twitter or use twitter, you can still use this link to read through these teaching sessions.