A young, previously fit man presents with a one week history of a 'flu-like illness which hes worsened over the past 24 hours. His temperature is 39.5 °C with a heart rate of 100 and increased respiratory rate. His chest X-ray shows diffuse mottled shadowing in both lung fields A diagnosis of community-acquired pneumonia is made and he is started on co-amoxiclav and clarithromycin. After 24 hours his condition has not improved, his temperature is 39 °C and a repeat chest X-ray reveals multiple nodular shadows with the possibility of a fluid level.A young, previously fit man presents with a one week history of a 'flu-like illness which has worsened over the past 24 hours. His temperature is 39.5 °C with a heart rate of 100 and increased respiratory rate. His chest X-ray shows diffuse mottled shadowing in both lung fields. A diagnosis of community-acquired pneumonia is made and he is started on co-amoxiclav and clarithromycin. After 24 hours his condition has not improved, his temperature is 39 °C and a repeat chest X-ray reveals multiple nodular shadows with the possibility of a fluid level.