Table 1 Criteria for defining pneumonia

Radiological signs

 Two successive chest radiographs showing new or progressive lung infiltrates

 In the absence of medical history of underlying heart or lung disease, a single chest radiograph is enough

And at least one of the following signs

 Body temperature > 38,3 °C without any other cause

 Leucocytes < 4000/mm³ or ≥ 12,000/mm³

And at least two of the following signs

 Purulent sputum

 Cough or dyspnoea

 Declining oxygenation or increased oxygen requirement or need for respiratory assistance