Pulmonary arteriovenous malformation: a rare cause of dyspnoea on exertion.

To cite: Mangla A, Nevares A, Yamani N, et al. BMJ Case Rep Published online: [please include Day Month Year] doi:10.1136/ bcr-2014-204087 DESCRIPTION Pulmonary arteriovenous malformation (PAVM) is caused by the abnormal connection between pulmonary arteries and venous systems. First described in 1897 by Churton, PAVM is a rare disease. In an autopsy study in 1953 at Johns Hopkins, only 3 cases of PAVM were detected out of 15 000 consecutive autopsies. PAVM are present in 15–50% of patients with hereditary haemorrhagic telangiectasia (HHT), also known as Osler-Weber-Render disease; however 70% cases of PAVM are associated with HHT. A 69-year-old woman with a history of hypertension, diabetes, dyslipidaemia and hypothyroidism presented with a history of progressively increasing dyspnoea on exertion over past 3 months. She denied any history of chest pain, palpitations, presyncope or syncope. At admission pulse oximetry showed 83–90% saturation on room air, correcting to 95–96% on supplemental oxygen. Physical examination was significant for a faint bruit on right infrascapular region. Arterial blood gas (ABG) showed elevated Alveolar-arterial (A-a) gradient of 44.1 mm Hg (normal for age was 17 mm Hg). Chest X-ray (CXR) showed a 3 cm tubular opacity in the right lower lobe (figure 1). CT angiogram confirmed the diagnosis of pulmonary arteriovenous malformation (AVM; figure 1). Two-dimensional