Differential diagnosis
The table summarizes the most common diseases, that present with consolidation.
Chronic diseases are indicated in red.
A way to think of the differential diagnosis is to think of the possible content of the alveoli:
 - Water - transudate.
 - Pus - exsudate.
 - Blood - hemorrhage.
 - Cells - tumor, chronic inflammation.
Another way to think of consolidation, is to look at the pattern of distribution:
 - Diffuse - perihilar (batwing) or peripheral (reversed batwing).
 - Lobar or focal.
 - Multiple - usually multiple ill-defined densities.
Now it is obvious that some diseases can have more than one pattern.
For instance a lobar pneumonia caused by streptococcus pneumoniae may become diffuse if the patient does not respond to the treatment.
Other examples are organizing pneumonia (OP) and chronic eosinophilic pneumonia.
These diseases typically present as multifocal consolidations, but sometimes they may become diffuse.
OP is organizing pneumonia. When it is idiopathic it is called cryptogenic (COP). The old name is BOOP - Bronchiolitis Obliterans Organizing Pneumonia.
The new name for BAC - bronchoalveolar carcinoma is adenocarcinoma in situ. #Diagnosis #Radiology #Pulmonary #CXR #Consolidation #Lobar #Diffuse #Multifocal #Differential #Table #RadiologyAssistant