HIDDEN IN PLAIN SIGHT: NEW DIAGNOSIS OF PULMONARY ARTERIOVENOUS MALFORMATION AFTER ISCHEMIC COLITIS

Abstract

SESSION TITLE: Medical Student/Resident Pulmonary Vascular Disease Posters SESSION TYPE: Med Student/Res Case Rep Postr PRESENTED ON: October 18-21, 2020 INTRODUCTION: Pulmonary arteriovenous malformation (PAVM) is an abnormal connection between a pulmonary artery and vein, which allows blood to bypass the filter function of the capillary beds and delivers deoxygenated blood to the left heart. This condition often remains undiagnosed until thromboembolic complications present. We report the case of new diagnosis of PAVMs in a patient presenting with ischemic colitis. CASE PRESENTATION: A 58-year-old female presented with acute onset diffuse abdominal pain and emesis. She was afebrile and normotensive with nonspecific abdominal tenderness on examination. Laboratory data was significant for mild leukocytosis and normocytic anemia. Computer Topography (CT) abdomen and pelvis showed diffuse inflammation around the cecum, consistent with ischemic colitis. She underwent partial colectomy with ileostomy placement. Postoperatively, she developed acute hypoxemia. CT angiogram showed left lower lobe pulmonary embolus and multiple PAVMs (largest in left lower lobe). She was treated with anticoagulation. However, she remained hypoxic and required oxygen at discharge. Further history revealed episodic epistaxis since childhood, three prior stillbirths, miscarriage, and multiple strokes in her sister. Hypercoagulable work-up was negative. She was readmitted multiple times for hypoxia and has undergone numerous PAVM embolization procedures. Post-embolization bubble echocardiogram showed intra- and extra-cardiac shunt both confirmed by transesophageal echocardiogram. DISCUSSION: Most PAVMs are hereditary with over 80% occurring in association with hereditary hemorrhagic telangiectasia, an autosomal dominant vascular disorder. Less commonly, PAVMs are idiopathic or secondary to trauma, infection or due to hepatopulmonary syndrome. Previously viewed as rare conditions, recent data suggest PAVMs affect 1 in 2,600. Patients with PAVMs present with hypoxemia and paradoxical embolization complications, including stroke, brain abscess, and other end-organ ischemia as seen in our patient who presented with ischemic colitis. A history of recurrent nosebleeds since childhood and family history of strokes were subtle clues to the diagnosis, but as in many other cases, the PAVMs were not identified until she presented with a paradoxical thromboembolic event. Patient has persistent hypoxemia despite embolization, and we hypothesize that obliteration of the large PAVMs led to elevated pulmonary pressures, which opened the intra-cardiac shunt in addition to new intra-pulmonary shunts. CONCLUSIONS: Pulmonary AVMs often remain undetected in patients until a thromboembolic complication occurs. Increased awareness of variable presentations of pulmonary AVMs is essential for prompt diagnosis and treatment to prevent devastating complications. Reference #1: Shovlin, C. Pulmonary arteriovenous malformations. Am J Respir Crit Care Med. 2014 Dec 1; 190 (11): 1217-1228. Reference #2: Lovering, A et al. Pulmonary pathways and mechanisms regulating transpulmonary shunting into the general circulation: An update. Injury. 2010 Nov; 41(0 2): S16-S23. Reference #3: Lee, W et al. Contrast echocardiography remains positive after treatment of pulmonary arteriovenous malformations. Chest Journal. 2003 Feb; 123 (2): 351-358. DISCLOSURES: No relevant relationships by RAMYA GORTHI, source=Web Response No relevant relationships by John Mwangi, source=Web Response No relevant relationships by Mackenzie Steck, source=Web Response