INTRODUCTION: Pulmonary arteriovenous malformations (AVMs) have shown to clinically deteriorate during pregnancy, frequently during the second and third trimester(1). We report the case of a young woman in her first trimester of pregnancy presenting with spontaneous abortion and profound hypoxemia due to diffuse pulmonary AVMs.
CASE PRESENTATION: An eighteen-year old African American woman at 12th week of her first pregnancy presents with vaginal bleeding, abdominal pain and chronic shortness of breath. She denied smoking or current medication use. She suffered from mild intermittent asthma treated with inhaled albuterol as needed since childhood. Her family history was non-contributory. Initial evaluation revealed patient to be tachycardic to 110 beats per minute, with a blood pressure of 138/68 mm/Hg, and oxygen saturation (SaO2) of 85-87% on room air that increased to 93% on 3 liters nasal cannula. Her physical exam revealed mild suprapubic tenderness and blood in vaginal vault. Missed abortion was confirmed by ultrasonography and treated with emergent dilation and curettage. The patient’s hypoxemia persisted despite supplemental oxygen and albuterol and ipratropium nebulizers. Chest radiograph showed no consolidation, effusion or pneumothorax. Computed tomography of the chest with intravenous contrast revealed several areas of small ground glass opacities some with vessels in their central region. There were no discrete nodules or obvious pulmonary arteriovenous malformations. A trans-esophageal echocardiogram with agitated saline showed left atrium opacification after 3.5 cardiac cycles. Bilateral selective and segmental pulmonary angiogram demonstrated diffuse innumerable pulmonary AVMs concentrated predominantly in the left lower lobe measuring between 1.0 and 3mm. The patient was medically managed with supplemental oxygen via nasal cannula. She declined any contraceptive method. Over the following 3 years, the patient had a second spontaneous abortion during her first trimester of pregnancy and three consecutive live births. Her respiratory status remained unchanged.
DISCUSSION: Pulmonary AVMs are abnormal communications between pulmonary arteries and veins that lead to right-to-left blood shunting. They could clinically manifest as persistent hypoxemia, hemoptysis, pleuro-pulmonary hemorrhages or as neurologic complications due to paradoxical embolization. Dyspnea could be masked as a pregnancy-related symptom, but evidence of hypoxemia is always pathologic. Progression of pulmonary AVMs during the second and third trimester has been linked to physiologic changes of pregnancy such as increase in total plasma volume and cardiac output. These changes promote blood flow across the pulmonary AVMs and its further dilation leading to increased shunting and hypoxemia. Out of twenty-six cases of pregnant patients with pulmonary AVMs reported(2), two patients developed symptoms during their first trimester. Enlargement of pulmonary AVMs during the first trimester has been linked to the vasodilating effects of progesterone(1). Our patient’s angiogram showed diffuse pulmonary AVMs, defined as AVMs in all sub-segmental arteries of at least one pulmonary lobe(3). This presentation is not often seen and difficult to detect by initial imaging studies. Patients with diffuse pulmonary AVMs have been able to conceive but the rate of fetal loss is increased(3) as showed in our patient. It is difficult to determine if our patient developed new arterio-venous malformations during pregnancy, or if her pregnancy-related hormonal changes dilated the clinically quiescent pulmonary AVMs.
CONCLUSIONS: Diffuse pulmonary AVMs may become clinically evident during the first trimester of pregnancy as unexplained hypoxemia in the setting of a spontaneous abortion.
Reference #1 Swinburne, A J Fedullo, R Gangemi and J A Mijangos. Hereditary telangiectasia and multiple pulmonary arteriovenous fistulas. Clinical Deterioration During Pregnancy. Chest 1986;89;459-460.
Reference #2 Andrea S. Gershon, Marie E. Faughnan, Kenneth S. Chon, et al. Transcatheter Embolotherapy of Maternal Pulmonary Arteriovenous Malformations During Pregnancy. Chest 2001;119;470-477
Reference #3 Marie E. Faughnan, Yvonne W. Lui, Joel A et al. Diffuse Pulmonary Arteriovenous Malformations. Chest 2000;117;31-38
DISCLOSURE: The following authors have nothing to disclose: Mauricio Danckers, Carlos Alviar, Ruth Minkin
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