HEMOPTYSIS WITH POSITIVE ANTI-GLOMERULAR BASEMENT MEMBRANE ANTIBODY WITHOUT RENAL INVOLVEMENT: UNUSUAL PRESENTATION; IS THIS TRULY AN ANTI-GLOMERULAR BASEMENT MEMBRANE DISEASE?

Abstract

SESSION TITLE: Medical Student/Resident Pulmonary Manifestations of Systemic Disease Posters SESSION TYPE: Med Student/Res Case Rep Postr PRESENTED ON: October 18-21, 2020 INTRODUCTION: Anti-GBM disease is a small vessel vasculitis affecting glomerular and pulmonary capillaries due to deposition of anti-GBM autoantibodies along basement membrane. It is characterized by a triad of pulmonary hemorrhage, crescentic glomerulonephritis and circulating anti-GBM autoantibodies (1). In rare cases, pulmonary disease predominates. We report a patient with hemoptysis who was found to have positive anti-GBM Ab but normal renal function. CASE PRESENTATION: A 74-year-old male with 30 pack year smoking history and emphysema came into ED with sudden onset hemoptysis. He reported dry cough and a low-grade fever for a month that did not respond to antibiotics. CT angiogram showed bronchial wall thickening in mainstem and perihilar bronchi and secretions in the left mainstem. No pulmonary embolism, aneurysm or AVM was noted. Laboratory findings included hemoglobin drop from 17 to 14 mg/dl; normal white cell count, platelets, PT/PTT, serum creatinine, urinalysis and negative procalcitonin, respiratory viral panel, ESR and CRP. Bronchoscopy showed recent blood in left mainstem bronchus and multiple segmental bronchi with active oozing from inferior lingular subsegmental bronchus which was cauterized. There were no airway lesions to biopsy or broncholith eroding into the airway wall. BAL cultures were negative. On further testing, ANCA (MPO and PR3 IgG) antibodies, rheumatoid factor, anti-cyclic citrullinated peptide antibodies were not detected. However, serum ANA titer was 1:320 with speckled pattern and anti-GBM IgG antibody was 55 AU/ml. He was started on prednisone taper. Multidisciplinary discussion was held as with lack of inflammatory markers and classic radiographic findings, it was not clear if he truly had anti-GBM disease. Repeat serum ANA and Anti-GBM antibody were positive with a decrease in anti-GBM antibody titer from 55 to 41 AU/ml. Kidney biopsy was not obtained due to lack of renal involvement. He was continued on prednisone taper with initiation of mycophenolate. At 6 months follow-up, his anti-GBM titer decreased to 27 AU/ml without recurrence of hemoptysis or renal involvement. DISCUSSION: Pulmonary predominant anti-GBM disease is rare and accounts for <10% of all cases [1]. Our patient presented only with hemoptysis with no typical radiographic findings (diffuse alveolar hemorrhage) or renal involvement. It is possible that smoking or a respiratory infection triggered mucosal injury causing hemoptysis and positive anti-GBM Ab was an incidental early finding [2,3]. However, no other possible explanation for hemoptysis was found on bronchoscopy and his high titer of anti-GBM Ab decreasing with immunosuppressants makes this a plausible diagnosis. CONCLUSIONS: Clinicians should consider anti-GBM disease when patients present with hemoptysis without obvious etiology. Early diagnosis and treatment could potentially delay or even prevent renal involvement and may improve outcome. Reference #1: Justin A. Edward, Jeffrey S. Lee, Peter K. Moore, Andrew K. Levy. A Man in His 50s With Hemoptysis, Dyspnea, and Bilateral Patchy Ground-Glass Opacities. CHEST 2019; 156(2):e41-e45 Reference #2: Chin Jung, George Karpouzas, William W. Stringer. Dyspnea, Hemoptysis, Perihilar infiltrates in a 35-year-old man. CHEST 2005; 127:1437-1441 Reference #3: Emily Ann Boardman, Sameira Sohail, Rajesh Yadavilli. Goodpasture’s disease with late presentation of renal abnormality and anti-GBM autoantibody. BMJ Case Rep 2017. doi:10.1136/bcr-2016-218705 DISCLOSURES: No relevant relationships by Maria Azhar, source=Web Response No relevant relationships by Sukrita Menon, source=Web Response No relevant relationships by harikrishnan nandakumar, source=Web Response No relevant relationships by Ji Hyun Rhee, source=Web Response