A man with fever and breathlessness

A 42 year old man, born in Zimbabwe and living in the UK, presented with a two week history of fever, vomiting, and diarrhoea on a background of six months of increasing exertional dyspnoea. His temperature was 38°C, heart rate 96 beats/min, respiratory rate 24 breaths per minute, blood pressure 82/57 mmHg, and saturations 100% on room air. On examination there was a loud first heart sound and mid-diastolic murmur. Blood results are shown in the table. View this table: Relevant abnormal blood results He underwent chest radiography (fig 1). Fig 1 Chest radiograph He was treated for septic shock of unknown origin with piperacillin-tazobactam and 4000 mL intravenous fluid, after which he developed bilateral coarse crepitations on auscultation and marked type 1 respiratory failure. He improved after 12 hours of ventilation on the intensive care unit and was successfully extubated. Blood cultures were later positive for Streptococcus oralis . 1. What does the chest radiograph show? 2. What is the most likely underlying diagnosis? 3. What is the most likely cause of the rapid deterioration and improvement of respiratory function? ### 1. What does the chest radiograph show? It shows evidence of pulmonary oedema with perihilar congestion, fluid in …