Idiopathic pulmonary arteriovenous malformation: a rarity in clinical practice

Pulmonary arteriovenous malformations (PAVM) are characterized by abnormal pulmonary vessels forming arteriovenous shunts that compromise oxygenation of the blood, causing hypoxemia, and predispose to infections and cerebral ischemia. The patient in this case was a 38-year-old male who presented with tachypnea and dyspnea, cyanosis of extremities, and significant digital clubbing. The patient had structural epilepsy secondary to neurosurgery for a cerebral abscess during childhood. Arterial blood gas analysis showed significant hypoxemia (PaO₂ = 46.2; SaO₂ = 77%; PaO₂/FiO₂ = 70) and a chest computed tomography showed PAVM in the apical segments of the right upper and lower lobes, with ectatic and tortuous vascular structures following an intraparenchymal path, communicating with the pulmonary artery and veins. After confirmation of the PAVM, it was concluded that elevated pulmonary resistance was contributing to refractive hypoxemia and hypercapnia. Gradual reduction of the ventilation parameters, primarily controlled pressure and positive end-expiratory pressure, and consequent reduction of the arteriovenous shunt, resulted in progressive improvement of oxygenation and respiratory mechanics. The vascular surgery team's assessment was that treatment with embolization was warranted.