ACUTE FIBRINOUS AND ORGANIZING PNEUMONIA: A RARE CAUSE OF INTERSTITIAL LUNG DISEASE

Abstract

SESSION TITLE: Tuesday Medical Student/Resident Case Report Posters SESSION TYPE: Med Student/Res Case Rep Postr PRESENTED ON: 10/22/2019 01:00 PM - 02:00 PM INTRODUCTION: Acute fibrinous and organizing pneumonia (AFOP) is a rare cause of interstitial lung disease that is commonly misdiagnosed in patients presenting with diffuse alveolar opacities. Here we present a case of a 60-year-old previously healthy man who presented with fevers, shortness of breath and cough and was eventually diagnosed with steroid-responsive AFOP. CASE PRESENTATION: A 60-year-old otherwise healthy man presented to the hospital with shortness of breath, dry cough and recurrent fevers as high as 40C of two weeks duration. Physical exam was significant for a respiratory rate of 22, oxygen saturation on room air of 94% and bibasilar crackles. Lab work-up revealed elevated white blood cell count at 12K, erythrocyte sedimentation rate and C-reactive protein were highly elevated at >120mm and 190 mg/L, respectively. Respiratory viral panel and atypical respiratory bacterial culture were negative. Chest x-ray showed left basilar and right lower lobe opacities. After 4 days of broad-spectrum antibiotics, the patient failed to improve with paroxysmal high fevers and hypoxemia, requiring 3-5L of oxygen with nasal cannula. A high-resolution CT of the chest (Figure 1) showed worsening multi-focal parenchymal consolidation in the lower lobes and new patchy involvement in the upper lobes. Antibiotics were discontinued after bronchoscopy & bronchoalveolar lavage showed the absence of infectious organisms. Work-up for collagen vascular disease was negative. Biopsy of the lung parenchyma was done and showed prominent intra-alveolar fibrin, scattered inflammatory cells, and patchy intraluminal connective tissue consistent with AFOP. The patient was started on high dose oral prednisone of 80mg daily with a plan for a prolonged taper over 8 weeks. Over the next few days, his symptoms, oxygen requirements and chest X-ray findings all improved. The patient was discharged home with no oxygen supplementation. DISCUSSION: One of the rare histologic interstitial pneumonias, AFOP was first reported in 2002 (1). It is defined as a subgroup of idiopathic interstitial lung disease with acute lung injury characterized by intra-alveolar fibrin deposition and organization of loose connective tissue (2). Patients with AFOP tend to present with pulmonary as well as extra-pulmonary symptoms. Cough, both productive and non-productive, has been found to be the most common symptom, followed by dyspnea and fever. While AFOP can present as an idiopathic disease process, it has been found to be associated with other disease processes as well including autoimmune, infectious and connective tissue diseases.Treatment consists of systemic glucocorticoids and immunosuppression (3). CONCLUSIONS: AFOP is a rare histopathological diagnosis that requires a high degree of clinical suspicion for diagnosis. Increasing awareness of this entity might lead to earlier diagnosis and more prompt initiation of appropriate therapy. Reference #1: Beasley MB, Franks TJ, Galvin JR, et al. Acute fibrinous and organizing pneumonia: a histological pattern of lung injury and possible variant of diffuse alveolar damage. Arch Pathol Lab Med 2002;126:1064. Reference #2: Travis WD, Costabel U, Hansell DM, King TE Jr, Lynch DA, Nicholson AG, et al. An official American Thoracic Society/European Respiratory Society statement: update of the international multidisciplinary classification of the idiopathic interstitial pneumonias. Am J Respir Crit Care Med 2013;188(6):733–48. Reference #3: Bhatti S, Hakeem A, Torrealba J, et al. Severe acute fibrinous and organizing pneumonia (AFOP) causing ventilatory failure: successful treatment with mycophenolate mofetil and corticosteroids. Respir Med 2009;103:1764. DISCLOSURES: No relevant relationships by Shameek Gayen, source=Web Response No relevant relationships by Xiang Liu, source=Web Response No relevant relationships by Mahmoud Madi, source=Web Response