Chest radiographs (X-ray photographs) often show a pulmonary infection before physical signs of<unk>  are observable at all. This is 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.
Atypical pneumonia
Fungal pneumonia
Lobar pneumonia
Dust pneumonia
Viral pneumonia
Bacterial pneumonia
Lipid pneumonia
Lung abscess