Do we know the most common misdiagnoses?

David Ryon Dyspneadoc at AOL.COM
Mon Nov 5 18:40:59 UTC 2018

I’ll chip in a first draft from Pulmonary and Critical Care. I’m not aware whether the question has been formally assessed; it fails a Google screening.  But as practicing pulmonologist we see these things frequently:

1. Pneumonia.  This is frequently missed, with radiographic findings attributed to other causes ( most frequently CHF), or it is overdiagnosed, when radiographic findings are actually old, or due to atelectasis, or to an uncommon lung condition such as fibrosis or sometimes even lung cancer. Many practitioners don’t realize that it’s normal for a very elderly patient to present pneumonia only having lethargy, without cough, fever, or leukocytosis. On the other hand, it’s often standard of care (such as it is in community medicine) for infiltrates to initially be treated as pneumonia, considering less common diagnosis after the infiltrate doesn’t clear.

2. Asthma. Not unusual for us to see a middle aged or elderly patient newly misdiagnosed as having asthma, which is a chronic disease that usually starts in childhood.  A new diagnosis of ‘asthma’ in an older person should raise alarm bells that something is being missed. Commonly, the condition was ‘bronchial asthma’, an acute state of wheezing during a bronchial illness that does not require chronic management, or it is COPD, once the history of smoking over 20 pack years comes out and spirometry is performed. But sometimes new onset wheezing in an elderly person is a sign of an endobronchial tumor, some other tracheobronchial obstruction, or uncommon conditions like vasculitis affecting the lungs, for example.

3. Pulmonary embolism (PE). This diagnosis still gets missed, particularly when confounding findings are present on CXR (leads to diagnosis of pneumonia and early closure). PE is a recognized cause of persistent exacerbation od COPD symptoms. Finally, PE is normally discounted when a patient is supposedly anticoagulated, but I recently had a patient nearly go to comfort measures only because she was on warfarin when she presented with dyspneadoc and wedge-shaped peripheral infiltrates in setting of known metastatic breast cancer.  Her large PE was clearly visible on a standard contrast CT done earlier in her admission, for unresolving ‘pneumonia’ that turned out to be pulmonary infarction.

4. COPD. We periodically see smokers who were heuristically handed this diagnosis when they complained of dyspnea, but turn out to have normal spirometry. Then they are found to have dyspnea for other reasons, such as coronary artery disease or other heart condition, most commonly, though there are about a dozen differential diagnosis categories. Occasionally such patients present with MI.

5. Lung cancer. This diagnosis completely dominates all other cancers in global mortality, in part because its onset is insidious, avoiding  detection. Several traps here: with CXRs are no longer advised annually or pre-op and seemingly discouraged, providers can forget that the onset of cough in their smoker isn’t always just another COPD exacerbation, putting off the study, sometimes for months. Early tumors, and sometimes poorly located larger tumors do not show up on CXR. These people will need a CT scan for diagnosis, and persistent symptoms to justify the scan.  For heavy smokers, or those who quit in the past 15 years, annual Low Dose CT screening has been proven to catch a significant percentage of lung cancers early enough to make a survival difference. However, most offices don’t have processes for ensuring that their smokers actually get screened.  There are ‘breathalizer’ type screening devices being developed, which should help. Then there is the problem of following up results appropriately, and sadly, we rarely have the  ‘incidental’ discovery of a small lung nodule that became  incurable before the patient was notified. Most practices do not have an airtight process to prevent this tragedy. More details here:

Next: misdiagnosis in Critical Care.
Thanks for putting up with my long post, it’s a privilege to be here....

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