Imaging studies in suspected pneumonia
When assessing a radiographic abnormality suspicious for pneumonia, it is important to touch base with the referring physician. In particular, one should establish that the abnormality is in line with clinical suspicion. Not all pulmonary opacities on chest radiographs are due to pneumonia, and so patients should have some clinical evidence of infection such as fever, sputum production, or leukocytosis to make pneumonia the most likely diagnosis. A short-term follow-up chest radiograph after treatment is useful to confirm interval resolution of a suspected pneumonia after treatment.
It is also helpful to identify where the patient may have acquired the infection. Was it in the community, a hospital, a nursing home, or in a foreign country? The statistical likelihoods of different types of infection will vary in these different settings.
Lastly, one of the most important questions to ask is whether the patient is immunocompromised (e.g., if the patient has known cancer, has recently received chemotherapy, has undergone prior solid organ or bone marrow transplantation with associated immunosuppressive therapy, or has human immunodeficiency virus [HIV] infection). These patients are at a much greater risk for opportunistic infections, and this therefore would alter the major differential diagnostic considerations for the type of infection that may be present.
