Onset of symptoms is often gradual, but in necrotizing staphylococcal or gram-negative bacillary pneumonias patients can be acutely ill.

[3] Affected individuals may also complain of chest pain, shortness of breath, lethargy, and other features of chronic illness.

Presence of air-fluid levels implies rupture into the bronchial tree or rarely growth of gas forming organism.

Examination of the coughed-up mucus is important in any lung infection and often reveals mixed bacterial flora.

Fiber optic bronchoscopy is often performed to exclude obstructive lesion; it also helps in bronchial drainage of pus.