A 66 year old woman presented to the accident and emergency department with severe chest pain radiating to the back following several episodes of vomiting after a meal.

On examination, she was unwell with tachycardia and tachypnoea. Her blood pressure was 150/80 mm Hg in the left arm and 138/80 mm Hg in the right arm. Her past medical history included asthma, hypertension, and a previous transient ischaemic attack.

On admission, she had a mildly raised white blood cell count (14.3×10⁹/l) with neutrophilia (8.58×10⁹/l) and normal haemoglobin (143 g/l). Serum lactate was raised (3.6 mmol/l), but urea and electrolytes were normal. Chest radiography was performed and showed a right sided pleural effusion. Aortic dissection was suspected, and she underwent computed tomography of the chest, abdomen, and pelvis using an aortic protocol. The scan showed a pneumomediastinum with an associated pneumothorax and a right sided pleural effusion. Further radiological investigation was performed (fig 1⇓).