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

Epidemiology

There tends to be a higher prevalence in older patients with alcohol use and debilitated hospitalised patients ³.

Pathology

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 ². This organism can cause extensive pulmonary necrosis and frequent cavitation ¹.

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 that 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 recognised complication.

CT

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

• ground glass opacities: considered relatively common ⁵

• consolidation: considered relatively common ⁵

• intralobular reticular opacities

• centrilobular nodules

• interlobular septal thickening

• cavitation

• pleural effusions

Necrotising pneumonia can occur as a complication ⁶.

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 ^7,8.

See also

• pneumonia