An unusual presentation of pulmonary artery dissection.

A morbidly obese woman presented with exertional dyspnoea and leg swelling. Past medical history included deep venous thrombosis and atrial fibrillation. Arterial blood gases demonstrated chronic respiratory acidosis and type 2 respiratory failure. Further evaluation consisted of spirometry (restrictive defect), Epworth scoring, overnight pulse oximetry (median oxygen saturation 68%) and echocardiography (pulmonary artery pressure 59 mm Hg). CT pulmonary angiography excluded signs of acute or chronic thromboembolism but demonstrated a 4 cm long dissection flap in the lower lobe segmental branch of the left pulmonary artery (fig 1).