Two Tales of Cognitive Diagnostic Error


Health care is busy! We have patients on patients on patients. They come one right after the other, and we have little time between to catch up on documentation. As a matter of fact, most clinics/companies prefer you document while you’re with the patient. All of this leaves little time to reflect on your decision-making with each patient, and this might be a bigger problem than you realize.

Here are two case reports that illustrate examples of cognitive diagnostic error perfectly, both experienced just last week* by yours truly. One, I caught and helped; the other…my mistake.

Lets start with my mistake…get it out of the way ūüėČ

(Case 1)

It was a busy day, I was filling in at another clinic within the company. My last patient encounter had run over, which was okay because my current patient was late! This next patient was in for an initial evaluation, and had just been added to my schedule an hour before. As a result, I had not had a chance to review her chart¬†before calling her back to the exam room, and I was in a rush to get to the following patient on time. The current patient to be evaluated was a business woman in her early 40’s. Let’s call her Karen. ¬†She was slim and fit, well kept. ¬†Karen was referred to me with a diagnosis of a left-sided cervical radiculopathy. The pain had just started a week ago, so she was pretty “hot” and irritable in regard to pain and attitude. Head movements triggered the pain, even certain arm movements triggered the pain. The pain was localized¬†to her lateral arm and upper trap. She was tense and guarded with all of her movements, but her pain mostly matched a radicular pattern and style. She was weak, secondary to pain. Given the acute nature of her situation (i.e. 1 week from onset), and the prompting from the referral, and my desire¬†to “hurry up” so that I would not make my next patient (who was on time) wait, I wrapped up my exam and provided¬†Karen with some movements and recommendations for addressing the issue. I also explained that given the acuity of the situation, it may take a few more days to calm down and notice any change. She understood and thanked me. I had her schedule to be back in on my next day back at that particular clinic, so that I could personally follow-up with her.

About 4-5 days later, Karen returned to the clinic (I think she was late again). She had calmed down a bit, so that her pain was a bit more tolerable. Her pain, however, was still there. She didn’t display any directional preference in terms of a cervical radiculopathy. I had a bit more time with Karen this session, and decided to take another look at what was going on. She was responding the way I hoped and certain exercises caused her pain to increase (certain ones you wouldn’t expect).

Upon further, closer examination and more detailed history taking it was clear that Karen did not have a cervical radiculopathy. I explained to her that, given her high level of physical activity (weight lifting, kick boxing, occasional cross fit), and her present signs and symptoms she likely had a simple case of rotator cuff tendonitis. We adjusted course (or I left documentation for the following PT and PTA to adjust course as I wouldn’t be continuing at that clinic any longer), and she was thankful.

It wasn’t a huge deal. She had 1 extra treatment day with an incorrect diagnosis and she didn’t seem to mind the mix-up, but I felt stupid. I had entered Karen’s initial examination with a mindset that was rushed and hurried. I had modified my typical examination procedures for the sake of time, and didn’t bat an eye or even stop the think about an alternative. As soon as her pain was modified with neck movement (or at least seemed to be), I settled on that as my diagnosis and planned a course of treatment.

(Case 2)

Debra was a late 30’s, heavy-set woman. She had a moderate intensity job (custodial staff at a local school), with a high intensity persona. Upon calling her back from the waiting room, she looked at me and said, “I got you today?!” I think I saw a smirk.

She was being seen for anterior ankle pain, referred by a podiatrist. He had attempted to treat her with injections and medications to no avail. After the “conservative” measures, he ordered an MRI, and had finally sent her to physical therapy with the comments “ankle instability and pain; chronic ATFL tear.”¬†Debra¬†was on visit #9 in about 3 weeks, this was my first time treating her. She had been through a bunch of ankle¬†strengthening and stability exercises, along with some modalities to help her pain. She was being seen for approximately 45+ mins each session. All of this, and her pain was just the same as when she started…her words paraphrased.

Being my first encounter with Debra and her lack of progress, I decided to do a bit of a re-examination. She had finished her warm up on the recumbent bike, so I called her over to a plinth. She was short sitting on the edge of the table. I revisited the details of her initial onset of pain, it was insidious. She didn’t have a clear MOI for her chronic tear (and I wasn’t really buying this being a sudden contributor to her pain, obviously). I asked her to describe the pain, to put it into words for me. She pointed right to the front of her ankle and said, “it feels like someone is jabbing a needle in there.”¬†Something kinda tingled in the back of my brain when she said that…a small notification or alarm. I tried to do some isometrics into dorsiflexion, see if that relieved any pain (more of a shot in the dark at the moment, admittedly). She had no weakness with her resistance…and no pain relief either. I explained briefly purpose of that exercise and clarified, that they don’t always work. I asked to her stand up to walk around. She slid off the edge of the plinth, stepping gingerly initially, then smoothed out into her regular gait. I asked her what that was about. She said it had been hurt worse since we had been talking, maybe it was the “iso exercises,” but the pain leveled out after she was up and walking for a few steps.¬†I felt that tingling, that alarm going off again, but this time I knew why it was there.¬†She had more pain since sitting in a slumped position, less once she straightened up a bit.¬†She was having radicular pains.

I told Debra to lay flat on the table on her stomach, and after a few minutes and performing some directional preference exercises, her pain was gone. Debra was completely stumped. She was trying to figure out what had happened to make her pain go away so easily, while was trying to figure out why she was nearing her return to the podiatrist, who was already talking about surgery with no resolution to a simple problem — until now.

Cognitive diagnostic errors are mostly rooted in forms of bias, but it does seem that some of them are a bit outside the box of biases. Triage cueing is one form of cognitive diagnostic error.¬†Which is the tendency for a professional to treat a patient as if they automatically require our services — because they were sent to us with that assumption. There’s a saying that describes this, “geography is destiny.” This can refer to a person’s geographical location, or it can refer to the cardiac unit (for example) they’ve been referred to. The result is that the individual will be treated as a cardiac patient because they are in the cardiac unit, not necessarily due to a cardiac condition requiring cardiac treatment.

In the cases above there are examples of triage cueing, but also other cognitive diagnostic errors, like diagnosis momentum**,¬†the bandwagon effect***, anchoring bias****,¬†and others. These cognitive diagnostic errors are sticky and they build on each other, complicating things. The effects of these cognitive diagnostic errors can be minimal like in¬†Case 1, or potentially drastic like in¬†Case 2 (where Debra was close to having a completely unnecessary surgery). The necessity for us as clinicians to have rest and reflection time has never been so overlooked as it is today. This is at a time when we have such a wealth of knowledge of the human body, pathologies and conditions, and pain neurophysiology’s complexity and quirkiness; this may be the time we most need…time.


*This post was started and finished at separate dates, quite separate.

**Diagnosis Momentum -an essential snowballing effect that occurs once a diagnosis is place on a patient (labels are sticky!)

***The Bandwagon Effect Рthe tendency to think or behave in a way because other people are doing the same.

****Anchoring Bias – the tendency to latch onto salient features early on in the diagnostic process and failing to adjust interpretation once other features are display later in the process.

Here’s another post about bias and cognitive errors if you’re interested.

One thought on “Two Tales of Cognitive Diagnostic Error

  1. Hi Spencer: I have a couple of comments. You really did not misdiagnosis Karen. If treating her neck relieved some of her pain then there was some kind cervical influence on her shoulder problem. Not treating her neck would probably reduced the effectiveness of isolated treatment the rotator cuff tendinitis. The longer that you are in this business, the more you find out how things are interconnected.

    I have a serious issue with the second case. Why was Debra treated for 3 weeks without obvious improvement? Kudos to you. You fixed the problem in one session. Nine sessions is certainly good for the bottom line of the clinic but it doesn’t help the credibility of our profession. I hope that you gave the staff at that clinic an inservice on basic foot and ankle mobilization.

    Cheers, Brian


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