A young couple both presented in the autumn of 2013 with a protracted flu-like illness, right-sided pleuritic chest pain and night sweats. Neither had any significant past illnesses nor had they travelled abroad recently.

Patient X (aged 18 years) was systemically well with no extrapulmonary abnormalities on examination. Her C-reactive protein was elevated at 46 with a normal white cell count and negative blood cultures. She was not immunocompromised. Chest X-ray and thoracic ultrasound revealed a small right-sided pleural effusion. She was extremely needle phobic, and so pleural aspiration was not performed. She was treated for pneumonia with a 4-week course of oral antibiotics and clinically improved.

Patient Y (aged 20 years) presented to chest clinic 1 month later. On examination, he was septic. Chest X-ray, thoracic ultrasound and pleural aspiration confirmed that he had a right-sided empyema. He was admitted and treated with intravenous antibiotics and an intercostal …