What is the most likely diagnosis for a febrile patient with a WBC count of 22,000 and moderate respiratory distress?

The diagnosis of bacterial pneumonia is supported by the combination of fever, elevated white blood cell (WBC) count, and moderate respiratory distress. In cases of bacterial pneumonia, patients often present with fever as the body mounts an immune response to the infection. The significantly elevated WBC count indicates the presence of an active infection, which is commonly associated with bacterial causes.

Also, respiratory distress can occur because the infection leads to inflammation and consolidation in the lungs, impairing gas exchange and causing difficulty breathing. This scenario is characteristic of bacterial pneumonia, where the body's response to infection results in symptomatic presentations.

In contrast, while viral pneumonia and acute bronchitis can cause respiratory symptoms, they typically do not lead to such a high WBC count; viral infections often result in lower WBC counts or a predominance of lymphocytes. Pleurisy can cause chest pain and breathing difficulties but generally does not lead to a significant increase in WBCs unless there is an associated infection like pneumonia. Thus, the clinical presentation aligns most closely with bacterial pneumonia, making it the most likely diagnosis.