A 19-year-old female with sickle cell disease presents to the emergency department in acute pain that she describes as most severe in her legs and back and radiating to her abdomen. A frequent visitor to the ER with painful crises, the patient is convinced this is just another episode, and emergency medicine physician Dr. Gita Pensa treats her accordingly. When the pain worsens, Dr. Pensa questions her original diagnosis, and realizes the one crucial bias that nearly blinded her from correctly diagnosing the patient.
Gita Pensa, M.D., FAAEM
Dr. Gita Pensa is a Clinical Assistant Professor of Emergency Medicine with the Brown Emergency Medicine Residency Program. She has an interest in digital medical education and is the editor of the Brown Emergency Medicine blog, as well as the Associate Director – Education of Brown’s Emergency Digital Health Initiative (EDHI). She is the lead podcaster for the Academic Emergency Medicine journal, and editor of the AEM Early Access podcast. Find her on Twitter at @GitaPensaMD. See more cases from the Brown Emergency Medicine Residency Program on Figure 1 at @BrownEM.
Marjorie P. Stiegler, M.D.
Dr. Stiegler is a Harvard-trained physician specializing in anesthesiology. Since 2005, her academic focus for research, writing, and speaking has been the application of behavioral psychology to patient safety in medical settings. She has given over 100 presentations across the globe on the role of cognitive bias in medical decision making, expertise, and error. Her publications can be found here. Dr. Stiegler also has a professional blog and can be followed on Facebook and Twitter at @drmstiegler. Her book “Quality and Safety in Anesthesia and Perioperative Care“ is available on Amazon.
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DDx SEASON 1, EPISODE 2 TRANSCRIPT
Anchoring bias and the frequent flyer
RAJ: The patient is a 19-year-old woman who presents to the emergency department with acute total body pain. It’s most severe in her legs and back and radiates to her abdomen.
This is DDx. A podcast from Figure 1 about how doctors think.
I’m Dr. Raj Bhardwaj.
Today’s case comes from Dr. Gita Pensa.
PENSA: I’m an emergency physician working in Rhode Island and I am a clinical assistant professor of emergency medicine with the Brown University emergency medicine residency.
RAJ: As emergency physicians, most of the patients we see are complete strangers to us – they walk in the door, we meet them for the first time, we treat them, and then we may never see them again.
But there is another group of patients in the ER – the “frequent flyers” – patients with chronic conditions who we get to know after repeated visits.
This case involves one of those patients – a 19-year-old woman who Dr. Pensa and her colleagues had seen every few months over the course of a few years.
A quick note – The patient in this episode is represented by the voice of a professional standardized patient, like the ones used during clinical training and exams.
PENSA: So this was a young woman who I actually knew. She suffered from sickle cell disease and patients often present with these painful vaso-occlusive crises. So she came in complaining of what she referred to as her usual acute pain episode.
SP actor: (sound up) It hurts all over like it always does. But right now I’m feeling it the most in my legs and my back, and it’s kind of radiating around from my back to the front of my stomach. I just need my pain meds.
PENSA: She had had episodes like this before. She was quite emphatic that this was similar to her other pain crises. When she came in, until you got her pain under control, she didn’t want to talk a lot. And so I started down the path of treating her pain and I’m sending some blood work because often they can present with severe anemia. I wanted to make sure that there wasn’t any other acute complication of sickle cell going on. I started managing her pain, hydrating her because the usual course of events was that after a few rounds of pain medication and fluids, she would feel better and she would be ready to go home.
RAJ: When we I see sickle cell on a patient’s chart, I know that in addition to anemia, I’m looking for any signs and symptoms of infection, pulmonary embolism, or avascular necrosis of their bones.
I also have to be on the lookout for hypoxia, respiratory complaints, and chest pain.
Dr. Pensa’s patient didn’t present with any of these signs or symptoms. And her labs didn’t indicate anything abnormal.
PENSA: There wasn’t anything about it on the surface that was ringing any bells for me. So I wrote some orders and promptly went off to see my next patient.
RAJ: She expected that after a few rounds of pain medication and fluids, they’d likely be able to send the young woman home without admitting her. But then a nurse came to find Dr. Pensa…
PENSA: The nurse came to me and said, she’s complaining of worsening pain, mostly in the pelvis in the low back. I really think you need to come back and see her because her blood pressure is much lower and she seems like she’s really feeling poorly.
So whenever the nurse says, you better come back and see this patient, you better go back and see that patient.
I went back to re-examine her and she, she really did not look well. She was clammy, her blood pressure was very low. She had a thready pulse and when I went to re-examine her she was now complaining much more of abdominal pain. And her belly was now much firmer, much more tender. And I thought, well, I’ve missed something. What’s going on?
RAJ: In Emergency Medicine, we’re trained to think ahead: to anticipate the next potential complication, the next drug we might need to give, or the next treatment option if the first one doesn’t work. But we’re also trained to think back: to reassess our patient, re-examine them for new clues. Sometimes that means starting over, with an open mind and a broader DDx.
PENSA: When I went back from the beginning, and I’m very glad I did, I kind of went through the labs and there wasn’t anything there that was abnormal. And then I realized that in thinking solely about this patient as having sickle cell disease, I had ignored one of the cardinal rules of emergency medicine – which is to obtain a pregnancy test on every female patient between the ages of basically 10 and sixty.
RAJ: We’re always at risk of being burned by the un-performed test… blood glucose that changes the diagnosis from stroke to hypoglycemia; or from a child with gastroenteritis to a new diagnosis of Type 1 Diabetes; or a pregnancy test in any woman of child-bearing age…
PENSA: Her pregnancy test, which we added on very quickly came back positive.
PENSA: She was very convinced that this was her sickle cell disease. She […] did not really want to hear a thing about going to the operating room or that she was pregnant because she hadn’t known that she was. And so she and I both needed like a sort of paradigm shift in terms of thinking about what was going on that day.
She ended up having a very quick, gynecologic consultation, going to the OR and having surgery for a ruptured ectopic pregnancy.
RAJ: The patient ended up having a ruptured fallopian tube, which was removed. But she did well post-operatively. And a couple months later, Dr. Pensa saw her again in the ER.
PENSA: The next time I saw her we actually kind of had a laugh about it because she remembered that she was so convinced that it was her sickle cell disease too. Interestingly she wasn’t upset with me, which was good. She definitely saw it more as like, gosh, despite everything that I was telling you, you managed to figure it out anyway. And on my end I was thinking like, oh my God, I took so long to figure that out. Like she could have died in the meantime.
You know, after that I saw her multiple times over the years thereafter and um, it always was her pain. Every other time it was the disease, but just this one time… it wasn’t.
RAJ: Dr. Pensa often tells this story to her residents at Brown University as a cautionary tale about anchoring bias. That’s what happens when a physician gets stuck or anchors on an initial diagnosis, which can make it hard to notice what else might be going on.
This case is also a good example of confirmation bias.
STIEGLER: Confirmation bias is essentially selecting the data points that support the diagnosis you already believe to be true.
RAJ: This is Dr. Marjorie Stiegler, she’s an adjunct associate professor of anesthesiology at the University of North Carolina at Chapel Hill who has published extensively on cognitive biases in medicine.
STIEGLER: This patient came in all the time with the same constellation of symptoms. And both the patient and the physician thought they knew the diagnosis really before any evaluation or management had happened. So the patient believes she had a sickle crisis and she described the symptoms that are consistent with that. The physician thought she had a sickle crisis and so she looked for the data that supported that.
RAJ: Her near-miss experience with this case changed the way Dr. Pensa approaches cases where the patient is someone she’s seen before… or where the diagnosis seems obvious from the outset.
PENSA: Now in these scenarios, I may, you know, work a little harder just trying to prove to myself that, it is indeed what it seems to be, that you know, that it looks like a duck. And quacks like a duck. So it, you know, it is really, is the duck instead of a platypus. Do they quack? (laughs) I don’t know, but you want to just convince yourself that I’m right here.
RAJ: It can be tough to draw that line between what’s the logical or even obvious diagnosis and what might be too much of a snap judgement. Dr. Stiegler says it makes sense for physicians – especially those of us in the ER – to jump to the most obvious diagnosis first.
STIEGLER: When a medical student comes in and begins to learn medicine, they don’t recognize patterns and constellations of symptoms for the individual diseases, and experts can do that in a matter of minutes. So the development of these biases is not bad. It’s in fact linked directly to expertise and almost always gives us the right answer.
PENSA: I’m glad that this happened to me relatively early in my career. I think that there’s that sort of, of learning curve where you’re never quite as cocky as when you’re a senior resident and then when you come out as an attending you start to realize like, oh my gosh, there’s a lot that I didn’t know. And then your confidence plummets and then it kind of comes back up. I think it was kind of coming back up and then, you know, you get pulled down a couple of notches by a case like this.
Thanks to Dr. Gita Pensa and Dr. Marjorie Stiegler.
This is DDX, a podcast by Figure 1, the knowledge-sharing app for doctors. Figure 1 is an app that lets doctors share clinical images and knowledge about difficult-to-diagnose cases.
DDx is produced by Earshot podcasts. Our executive producers are Jesse Brown and Corey Marr. And our theme music is by Nathan Burley
You can find full show notes, photos, related medical cases, and links to Dr. Stiegler’s publications on cognitive biases at Figure1.com/ddx.
And you can follow Dr. Pensa and the Brown Emergency Medicine residents on the Figure 1 app at BrownEM
I’m Dr. Raj Bhardwaj. You can follow me on Twitter at RajBhardwajMD.
Thanks for listening.