Atul Gawande is a human surgeon who writes fascinating books on medical errors and how they can be avoided. I have read all 3 of his books: Better, Complications, and The Checklist Manifesto. Having done so, you would think that I'd be prepared to recognize when I attempt to make them. Yet, that's not the case. Just like every doctor, there are errors in my logic/rational thought process that lead to misdiagnosis and mistakes.
I saw a case recently. It was an old dog Golden Retriever (13 years old). She came in for collapse, labored breathing, pale gums, and extreme lethargy. Based on the history and my physical exam findings, I suspected she was suffering a hemoabdomen - likely secondary to a ruptured splenic or hepatic tumor. I focused heavily on this diagnosis, although I did consider others - heart failure, rodenticide poisoning, etc. Still, in my mind, hemoabdomen until proven otherwise.
This is the first cognitive failure. Focusing too heavily on one diagnosis due to previous/recent experiences. I see these types of cases (hemoabdomens with ruptured abdominal tumors) ALL THE TIME. Thus, it is always a forefront diagnosis. This is an important step in formulating a differential list - recognizing patterns. The problem with recognizing patterns is that often we as doctors stop seeing the forest for the trees. That diagnosis pervades in our minds as THE diagnosis based on previous experience, making it difficult to see and accept any evidence that does not support that diagnosis.
On my physical exam, the patient had a significant arrhythmia - possibly consistent with hemoabdomen (very common), but also possibly primary heart disease (which can also lead to collapse, labored breathing, pale gums, and lethargy). I recommended xrays and bloodwork to the owner.
Then I went to pump while my techs took care of testing. About 30 minutes later, my technician came to me and said, "abdominal mass with metastatic cancer in the chest."
Error #2 occurred here. I went into the radiology room to review the xrays, and I already had an idea of what I was going to see. Thus, I tried to make what I saw on the xrays fit what I had already suspected (a ruptured abdominal tumor) and what my technician had diagnosed.
The dog did indeed have an abdominal mass. It was not ruptured. I recognized that immediately. The chest xrays were a little sticky. Initially, I diagnosed the dog with extremely enlarged tracheobronchial lymph nodes. I called this metastatic cancer.
The problem? The typical cancer of the spleen (hemangiosarcoma) doesn't usually show up in the lymph nodes like that when it metastasizes. The metastasis I should have seen (were this truly a metastatic hemangiosarcoma) would have been ill-defined, patchy nodules in the lungs. Instead, what I saw was likely a pneumonia/collapsed lung with retracted lung lobes (possibly a chronic lung disease). There are other cancers that this could have been that WOULD show up in the lymph nodes - like lymphoma. So it's not entirely impossible that this was metastatic cancer. It could have been pneumonia/chronic lung disease however.
I saw these things (the retracted lung lobes, the consolidation of the lung tissue) and yet, I must have subconsciously wanted a simple diagnosis to give the owner - a neat package to wrap up with a bow. So I ignored them (not deliberately, I am only understanding this in hindsight).
My next step was ultrasounding the abdomen. I did not see free fluid, so I knew that the tumor hadn't ruptured. I did find a large abdominal mass, but it didn't look like your typical malignant tumor. It wasn't cavitated and "nasty" looking - it was large but more smoothly marginated.
Bloodwork was fairly normal other than a pretty good anemia.
So, what I should have recognized was that several things were occurring here: the anemia was likely secondary to chronic disease of some sort. The lungs were probably a chronic problem, although possibly not. The splenic mass may have been an incidental finding or it may been cancer on the verge of rupturing. I **should** have recognized that this might be many different problems.
Yet my mind had decided this was metastatic cancer before seeing the xrays, and I made this fit, even though all the pieces weren't there.
In the end, the owner decided to euthanize her dog based on my diagnosis. Was it the wrong decision? Likely no. I do believe this dog had cancer. She was obviously very ill and needed a blood transfusion. I do not think my original clinical picture was correct though. In retrospect, I committed at least 2 significant cognitive errors that led to making a leap in deduction. I have to struggle to overcome this and find a way to prevent this in the future.
I've sent the xrays to a board-certified radiologist for review (professional interest). Once I have a better idea of what I was dealing with, I'll decide whether I need to contact the owner.
What do you think? If your dog was extremely ill, very elderly, and needed at least $1500 of treatment with a guarded prognosis for survival - would it matter if the doctor was right about the tentative diagnosis? If it was metastatic cancer versus some other terminal illness? If the doctor made a mistake in diagnosis and your pet was euthanized, would you want to know after the fact? Keep in mind that this dog was very ill and likely had some form of cancer - so the ultimate outcome would have likely been the same.
When I have the xrays back, I will let you know what the radiologist says. Try not to judge me too harshly.
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