RARE ACUTE FIBRINOUS PNEUMONIA ASSOCIATED WITH LEGIONNAIRE’S DISEASE

Abstract

SESSION TITLE: Medical Student/Resident Chest Infections Posters SESSION TYPE: Med Student/Res Case Rep Postr PRESENTED ON: October 18-21, 2020 INTRODUCTION: Acute fibrinous organizing pneumonia (AFOP) is a newly proposed, rare histological variant of subacute interstitial pneumonia, which can be fatal. This case report describes an uncommon case of AFOP. CASE PRESENTATION: A 79-year-old female presented to the emergency department (ED) with worsening shortness of breath associated with hemoptysis, fever, and chills. Past medical history of remote Stage 1B adenocarcinoma of the lung status post-definitive chemo-radiotherapy, hypertension, coronary artery disease and permanent atrial fibrillation. In ED, the patient was afebrile, tachycardic and tachypneic. Her physical examination was significant for inspiratory crackles and wheezing throughout the lung fields. Laboratory data included a WBC of 9.1 k/µL, hyponatremia (122 mmol/L). A chest CT scan showed areas of airspace opacities in the right upper and left lung base. Legionella pneumophila serogroup 1 antigen was positive, compatible with acute Legionnaires disease. The patient was treated with 8 days of Levofloxacin and discharged home. After 3 weeks, the patient reported minimal improvement of symptoms, persistence of fatigue and shortness of breath with 10 lb weight loss. Repeat CXR displayed consolidative opacities in the upper lobes bilaterally, unchanged from previous imaging. Given the persistent infiltrates, and concern for progression of her known malignancy, a CT-guided biopsy was done. It contained core fragments of lung parenchyma with interstitial fibromyxoid tissue and organizing fibrin; without evidence of granulomas/neoplasm. These findings were consistent with a diagnosis of AFOP. After 1 week of steroids, her CXR highlighted interval resolution of patchy parenchymal opacities and resolution of symptoms. DISCUSSION: AFOP is a rare pathological disease with only a few cases reported in the literature. The exact etiopathogenesis remains unknown and clinical manifestations are usually non-specific. CT findings typically consist of bilateral opacities and areas of consolidation, but a definite diagnosis is made via lung biopsy. Currently, there is no standard therapeutic regimen for AFOP and is under investigation, making it controversial. The small number of case reports have highlighted that patients respond positively with a longer course of corticosteroids and/or immunosuppressive agents(1). Our patient showed marked symptomatic and radio-graphic improvement within 1 week of steroid therapy. As such, shorter courses of prednisone treatments may be considered in the appropriate clinical setting and if associated with side effects & morbidity from steroids. CONCLUSIONS: The diagnosis of AFOB can be very challenging as the clinical picture may mimic other potential etiologies such as inflammatory lung disorders, or malignancy. The mortality rate of untreated AFOB is high and therefore, consideration of this diagnosis in the appropriate clinic context can be potentially lifesaving. Reference #1: Gomes, R., Padrão, E., Dabó, H., Soares Pires, F., Mota, P., Melo, N., Jesus, J. M., Cunha, R., Guimarães, S., Souto Moura, C., & Morais, A. (2016). Acute fibrinous and organizing pneumonia: A report of 13 cases in a tertiary university hospital. Medicine, 95(27), e4073. https://doi.org/10.1097/MD.0000000000004073 DISCLOSURES: No relevant relationships by Sanchit Chawla, source=Web Response No relevant relationships by Anu Suri, source=Web Response