A CASE OF ACUTE INTERSTITIAL PNEUMONIA

Abstract

SESSION TITLE: Lung Pathology 1 SESSION TYPE: Fellow Case Report Posters PRESENTED ON: 10/09/2018 01:15 PM - 02:15 PM INTRODUCTION: Acute interstitial pneumonia (AIP) is a rare and life-threatening condition resulting in acute respiratory failure. Early recognition is paramount as patients often deteriorate rapidly. The pathogenesis is not well understood. Computed tomography (CT) imaging may show a pattern similar to that observed in acute respiratory distress syndrome (ARDS) (1) and the histopathologic pattern is characterized by diffuse alveolar damage (DAD). CASE PRESENTATION: We present a 56 year-old male with a history of tobacco use and type-2 diabetes mellitus who presented with new symptomatic anemia (hemoglobin 7.3 mg/dL), fever (39.4 degrees Celsius), tachycardia, and a non-productive cough. Physical examination was unremarkable except for skin and conjunctival pallor. Laboratory values revealed neutropenia (absolute neutrophil count of 0.33 K/uL) and 33 percent blast cells on the differential. CT chest demonstrated bilateral ground glass opacities and small bilateral pleural effusions. A bone marrow biopsy and peripheral flow cytometry findings were consistent with acute myeloid leukemia (AML). Broad-spectrum antibiotics were initiated for neutropenic fever. The patient underwent bronchoscopy with bronchoalveolar lavage (BAL) and transbronchial biopsies to evaluate for infection prior to initiation of chemotherapy. Infectious work up and cytology findings were negative. Pathology from the biopsy demonstrated a mild inflammatory infiltrate with fibrin exudate and hyaline membranes consistent with DAD, a non-specific finding consistent with acute lung injury. The patient proceeded to develop acute hypoxic respiratory failure with rapidly rising oxygen requirements. Following a negative rheumatologic work up, a diagnosis of AIP was made. Pulse-dose steroids were initiated and over the next several days his respiratory status significantly improved. Steroids were tapered over the course of several months and he was able to tolerate initiation of chemotherapy. A follow up CT chest after one month showed improvement of the ground glass opacities noted on the initial scan. DISCUSSION: DAD in a non-specific histological finding that may result from various types of lung injury. When there is no known trigger, it is called AIP or Hamman-Rich Syndrome. The exact mechanism of AIP is not well understood. Treatment consists primarily of supportive measures, which may include mechanical ventilation and extracorporeal membrane oxygenation (ECMO) (2). Management of early stages of AIP has had some success with high dose steroids (3). Evidence for the role of non-steroid immunosuppressive agents is limited. CONCLUSIONS: Prompt recognition of AIP is critical. Despite treatment, it carries a poor prognosis. The mainstay of therapy consists of supportive measures and the use of steroids. AIP is a diagnosis of exclusion and one must consider other known causes of DAD, including infection, medications, and autoimmune processes. Reference #1: Avnon LS, Pikovsky O, Sion-Vardy N, Almog Y. Acute Interstitial Pneumonia–Hamman-Rich Syndrome: Clinical Characteristics and Diagnostic and Therapeutic Considerations. Anesthesia & Analgesia. 2009 Jan 1;108(1):232-7. Reference #2: Newmarch W, Puopolo A, Weiler M, Casserly B. Hamman-Rich syndrome: a forgotten entity. Monaldi Archives for Chest Disease. 2017 May 18;87(1). Reference #3: Suh GY, Kang EH, Chung MP, Lee KS, Han J, Kitaichi M, Kwon OJ. Early intervention can improve clinical outcome of acute interstitial pneumonia. CHEST Journal. 2006 Mar 1;129(3):753-61. DISCLOSURES: No relevant relationships by Michael Esposito, source=Web Response No relevant relationships by Craig Fryman, source=Web Response No relevant relationships by Becky Lou, source=Web Response No relevant relationships by Gulrukh Zaidi, source=Web Response