Diffuse pulmonary arteriovenous malformation presenting with secondary polycythemia and headaches: a case report

Pulmonary arteriovenous malformations are a relatively uncommon medical condition, affecting roughly 1 in every 2500 individuals. Of those suffering from pulmonary arteriovenous malformations, 80% have an underlying genetic condition: hereditary hemorrhagic telangiectasia.

We present the case of a 20-year-old Pakistani male with a history of persistent slower-onset frontal headaches that increased in severity within the course of the day. His hemoglobin was 18 g/dl, indicating polycythemia, for which he had undergone seven venesections in a month previously. His physical examination was unremarkable. His computed tomography scan depicted multiple dilated tortuous vessels with branching linear opacities in the right lower lobe of the lungs. The multiple feeding arteries were supplied by the right main pulmonary artery, and the large draining veins led to the right inferior pulmonary vein. This was identified as a diffuse pulmonary arteriovenous malformation. He was recommended for a right pulmonary artery angiogram. It showed multiple tortuous vessels with a nidus and large draining veins-features of a diffuse arteriovenous malformation in the right lower lobe of the lung consistent with the computed tomography scan. Embolization of two of these vessels feeding the arteriovenous malformation was conducted, using Amplatzer Vascular plug 2, whereas multiple pushable coils (five coils) were used for embolizing the third feeding vessel. This achieved 70-80% successful embolization of right pulmonary AVM; however, some residual flow was still seen in the arteriovenous malformation given the complexity of the lesion. Immediately after, his oxygen saturation improved from 78% to 96%.

Diffuse pulmonary arteriovenous malformations, as seen in this patient, are rare, accounting for less than 5% of total pulmonary arteriovenous malformations diagnosed. The patient presented with a complaint of progressive frontal headaches, which can be attributed to low oxygen saturation or the presence of a cerebral arteriovenous malformation. There was no history of hereditary hemorrhagic telangiectasia in the patient's family. Furthermore, although most patients with hereditary hemorrhagic telangiectasia and hence pulmonary arteriovenous malformation have complaints of iron-deficiency anemia, our patient in contrast was suffering from polycythemia. This can be explained as a compensatory mechanism in hypoxemic conditions. Moreover, the patient had no complaint of hemoptysis or epistaxis, giving a varied presentation in comparison with a typical pulmonary arteriovenous malformation.