Attention to pulmonary arteriovenous fistula in a case of transient hypoxemia and cerebral infarction during pregnancy: a case report and literature review

Background Pulmonary arteriovenous fistula is rare during pregnancy. Pulmonary arteriovenous fistula presents no pulmonary symptoms in most patients but can be exacerbated by pregnancy. If not diagnosed and treated promptly, pulmonary arteriovenous fistula can lead to respiratory failure, stroke, spontaneous hemothorax, or other fatal complications. Case presentation A 29-year-old healthy pregnant woman presented with a transient drop in blood oxygen level of unknown cause during a routine examination at 34 weeks of gestation and during a cesarean section at 38 weeks of pregnancy. The patient’s oxygen saturation quickly returned to normal and was not further investigated. On day 3 postpartum, the patient suddenly displayed slurred speech and right limb myasthenia. A head magnetic resonance imaging revealed cerebral infarction in the left basal ganglia. Subsequent computed tomography pulmonary arteriography revealed bilateral pulmonary arteriovenous fistula, which was likely the cause of cerebral infarction. The patient was transferred to the Department of Thoracic Surgery after one month of treatment and successfully underwent percutaneous embolization of pulmonary arteriovenous fistula. Conclusion Pulmonary arteriovenous fistula should not be neglected if a pregnant woman presents with transient hypoxemia and cerebral infarction. A transient decrease in pulse oxygen saturation that cannot be explained by common clinical causes can be an early warning sign of the disease. Early diagnosis and multidisciplinary management could improve the prognosis.