Diagnosis
Chest radiographs (X-ray photographs) often show a pulmonary infection before physical signs of atypical pneumonia are observable at all. This is called occult pneumonia. In general, occult pneumonia is rather often present in patients with pneumonia and can also be caused by Streptococcus pneumoniae, as the decrease of occult pneumonia after vaccination of children with a pneumococcal vaccine suggests.
Infiltration commonly begins in the perihilar region (where the bronchus begins) and spreads in a wedge- or fan-shaped fashion toward the periphery of the lung field. The process most often involves the lower lobe, but may affect any lobe or combination of lobes.
Read more about this topic: Atypical Pneumonia