A 44-year-old man was admitted to the intensive care unit for mechanical ventilation after developing pneumonia complicated by acute respiratory distress syndrome. Despite aggressive management, his gas exchange deteriorated, requiring his transfer to a specialist respiratory unit for veno–venous extracorporeal membrane oxygenation therapy. During this treatment, recurrent clotting of the extracorporeal filters led to him receiving additional heparin and epoprostenol sodium. His blood film, thrombophilia screen and bone marrow aspirate did not identify a cause for his thrombotic propensity. Soon after starting extracorporeal membrane oxygenation therapy he became agitated, less responsive and developed lateralised upper motor neurone signs. CT scan of the head (figure 1A) showed multiple areas of acute parenchymal haemorrhage that evolved on sequential imaging (figure 1B). However, after …