Ruptured pulmonary arteriovenous malformation

36-year-old male patient with no previous comorbidities presented with 2-week history of left-sided chest pain.

Plain radiograph revealed left pleural effusion with an added radioopacity in the left lower zone. Plain and contrast-enhanced CT thorax revealed an abnormal tortuous vascular structure in the left posterior basal segment with more than one feeding artery from left branch of pulmonary artery and multiple draining veins to left inferior pulmonary vein. Hemothorax was noted on the left with evidence of contrast leak.

Pulmonary arteriovenous malformations are rare low resistance, high flow abnormal vascular structures that connect a pulmonary artery to a pulmonary vein bypassing the normal capillary bed and resulting in an intrapulmonary right to left shunt [1]. Pulmonary AVMs are divided into simple and complex lesions. Complex AVMs account for approximately 20% of pulmonary AVMs.[2] Simple pulmonary AVMs are lesions defined as comprising of a single feeding artery connected through a bulbous aneurysmal non-septated communication with one or more draining veins. Complex AVMs are defined as lesions supplied by 2 or more feeding arteries connected via a septated aneurysmal sac to 2 or more draining veins [1]. Diffuse pulmonary AVMs involve every segmental or subsegmental type of arteries of atleast one lung lobe and are extensive [3].

The incidence of pulmonary AVMs is 2 – 3 per 100000 population. The condition remains under-recognized until 2^nd decade of life [1]. These patients maybe asymptomatic but may also present with features of hypoxia, fatigue, dyspnea and cyanosis. Right to let shunting can result in pulmonary embolism and may cause stroke or brain abscess. Less common but life-threatening complications include hemoptysis and hemothorax [4]. 50 – 80% of pulmonary AVMs occur in patients with hereditary telangiectasia[5]. Rupture of AVMs can be seen in hereditary telangiectasia and pregnancy from hormonal changes.

Pulmonary AVM is characterised by abnormal vascular structures that connect the feeding artery and draining veins. They appear on radiographs  as rounded well defined nodular lesions of varying size with dilated draining vessels and branching feeding vessels. On pulmonary arterial phase intense enhancement with demonstration of feeding and draining vessels is seen. Uncommonly non enhancing peripheral hypodense nodule is seen in thrombosed AVM [1].

Our patient presented with ruptured pulmonary AVM and was managed surgically by segmentectomy of the involved segment. Patient is stable and symptom-free at present. Hemothorax and hemoptysis, though life threatening are rare complications [4].

Massive hemoptysis and hemothorax have been reported with fatal outcomes but hemothorax that is not life-threatening as in this case has been very rarely described in literature[6].