Patient History: A 17-year-old boy presents to the emergency department complaining of severe chest pain and shortness of breath. He has had a sore throat for a few days and started developing pain in his back and arms, which has increased in severity. Six hours prior to admission he suddenly developed right-sided chest pain, which is worse on inspiration and associated with marked breathlessness. He has had previous episodes of pains affecting his fingers and back, for which he has taken codeine and ibuprofen. There is no family history of note. Physical Examination: He is unwell, febrile (37.8°C) and cyanosed.

His conjunctivae are pale. Pulse rate is 112/min and regular, and blood pressure is 136/85 mmHg. His jugular venous pressure is not raised, and heart sounds are normal. His respiratory rate is 28/min, and a right pleural rub is audible. The abdominal and neurological examination…