I've heard that there is something called a "subtle pneumonia".could you please explain what this is and the way it works?does it have a medical name?

Pneumonia: There are various descriptions of pneumonia, but I'm not familiar with the term "subtle pneumonia". The mildest form of pneumonia is a patchy lung involvement and is called bronchopneumonia. A more extensive pattern is lobar pneumonia. Bronchitis may be difficult to distinguish from bronchpneumonia as symptoms are similar and X-Ray findings are minimal at times.

Subtle Pneumonia: Either you do or don't have pneumonia. It may have been sounds heard by a stethoscope or your symptoms but not present on CXR. This would be enough evidence to treat. Sometimes these are called " soft signs".

The name: Indicates pneumonia that is not easily visible on CXR. Which usually indicates a small infiltrate and hence had to see on CR. Sometimes identified by looking for the silhouette sign. Though clinically it will be treated as walk in pneumonia