How do you use the chest x-ray during the evaluation of a suspected COVID19 patient? Our practice has been all over the map as we learn about the clinical course of this disease and how to allocate our resources effectively. Due to the lack of COVID19 testing, we have relied heavily on imaging and the simple chest x-ray. But how do we use this imaging modality effectively during the current pandemic?
- Multiple radiological organizations have come forward to state that CT should not be relied upon as a primary diagnostic/screening tool for COVID-19. The ACR is clear that no imaging is diagnostic.
- However if you have a high prevalence of COVID19 in your community (like us in NYC) and findings consistent with viral PNA on chest x-ray I think it pretty much nails the diagnosis, and without a reliable test many have been using the chest x-ray as a surrogate diagnostic tool. The utility of this strategy is questionable in my opinion.
- A CXR may sometimes exclude or rule in other conditions which would be a good reason to get one. Early in the pandemic outbreak in NYC I was getting chest x-rays for other possible diagnoses, and discovering in fact a lot of COVID19, which makes knowing when to order one for other reasons now more challenging.
- I have been surprised by COVID19. In Patients with AMS or dementia or atypical symptoms a chest x-ray has sometimes been a valuable tool to identify those who need to be placed in isolation and tested.
- The non-specific imaging findings are most commonly of atypical or organizing pneumonia, often with a bilateral, peripheral, and basal predominant distribution.
- CXR does not determine final disposition. Early on we were admitting lots of patients for positive chest x-rays. Now, if they look well, and have no significant tachypnea, or hypoxia I’m sending many of them home with close monitoring and strict return instructions.
- So is there utility in getting a chest x-ray if you suspect COVID19? I think the answer is not much. If your patient looks bad, they need admission regardless of what the chest x-ray looks like. If they look good and their chest x-ray looks bad they can still probably go home in most instances although I think many clinicians are understandably anxious about doing so.
- In patients who are poor historians (elderly, dementia, AMS, psychiatric illness) the chest x-ray as part of a screening evaluation can be helpful.
- We are not totally in the dark on the issue of radiographic imaging. Despite being a novel coronavirus with high morbidity it is still a respiratory viral pathogen. A review from the Cochrane Database of Systematic Reviews on chest radiographs for acute lower respiratory tract infections concluded that CXR did not improve clinical outcomes. I think this still holds with COVID19.
- Here is the clinical guideline I’m currently using.
- Bottom Line
- Lack of testing is hampering our ability to make good decisions. Reaching for the chest x-ray in most patients is probably not the answer, and likely leads to unnecessary admissions to beds we desperately need. The problem is we just don’t have a good way yet to tell who is going to deteriorate and who is just going have a bad viral pneumonia so clinical judgement and our rapidly growing experience is our best weapon for now. But unless new data comes our way saying specific radiographic findings lead to rapid deterioration opening pandora’s box with radiography during this pandemic may cause more problems than offer solutions. Use the chest x-ray wisely in these patients.
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