klebsiella pneumonia

Klebsiella pneumonia, also known as Friedländer pneumonia, refers to pneumonia resulting from an infection from the organism Klebsiella pneumoniae.


There tends to be a higher prevalence in older patients with alcoholism and debilitated hospitalized patients .


Klebsiella pneumoniae is among the most common Gram-negative bacteria encountered by physicians worldwide and accounts for 0.5-5.0% of all cases of pneumonia . This organism can cause extensive pulmonary necrosis and frequent cavitation .

Radiographic features

Plain radiograph

It is one of the causes that could be suspected when there is cavitatory pneumonia +/- a bulging fissure sign. Often there can be extensive lobar opacification with air bronchograms.

A helpful feature which may help to distinguish from pneumococcal pneumonia is that Klebsiella pneumonia develops cavitation in 30-50% of cases (in comparison, cavitation is rare in pneumococcal pneumonia). This occurs early and progresses quickly. Massive necrosis (pulmonary gangrene) is a recognized complication.


There can be variable features on chest HRCT which can also depend on current other organisms. The spectrum includes

Necrotizing pneumonia can occur as a complication .

History and etymology

The organism Klebsiella pneumoniae was first described by German microbiologist Carl Friedländer (1847-1887) in 1882, in a series of patients with Klebsiella pneumonia .

See also