Malformação arteriovenosa pulmonar idiopática: raridade na prática clínica

Abstract

Pulmonary arteriovenous malformations (PAVM) occur with abnormal pulmonary vessels, forming arteriovenous shunts, compromising blood oxygenation and causing hypoxemia, in addition to some clinical manifestations, mainly predisposition to infections and cerebral ischemia. Hereditary Hemorrhagic Telangiectasia is responsible for 80-95% of PAVM cases, and, when there is no clear characterization of the syndrome, PAVMs are classified as idiopathic. V.S.B., 38 years old, male, presenting with tachydyspnea, cyanosis of the extremities and significant digital clubbing. With no previous need for hospitalization or episodes of acute respiratory failure, he denied orthopnea, trepopnea, platypnea and paroxysmal nocturnal dyspnea. It reported structural epilepsy following neurosurgical intervention due to a brain abscess in childhood. Admission arterial blood gas analysis, using a mask with reservoir 15L/min, revealed significant hypoxemia (PaO2 = 46.2 mmHg / SaO2 = 77% / PaO2/FiO2 = 70 mmHg); and, on the chest computed tomography, it was seen: PAVM in the upper segment of the upper and lower lobes, with ectatic and tortuous vascular structures, with an intraparenchymal course, maintaining a relationship with the pulmonary artery and veins. The patient's initial respiratory condition worsened, and orotracheal intubation continued. After proving PAVM, it was realized that high pulmonary resistance contributed to refractory hypoxemia and hypercapnia. Then, the gradual reduction of ventilatory parameters, especially controlled pressure and PEEP, and, consequently, the arteriovenous shunt, resulted in a progressive improvement in oxygenation and ventilatory mechanics, culminating in successful extubation. The assessment by the vascular surgery team indicated treatment via embolization. Most PAVMs are oligo/asymptomatic and, therefore, underdiagnosed. It is essential to alert the medical community about this entity, aiming for early diagnosis and immediate intervention.