ACTINOMYCOSIS

Abstract

SESSION TITLE: Chest Infections 1 SESSION TYPE: Med Student/Res Case Rep Postr PRESENTED ON: 10/09/2018 01:15 PM - 02:15 PM INTRODUCTION: Actinomycosis is a rarely encountered infection and technically difficult to culture, hence may pose a challenge for the clinician. Awareness regarding this uncommon infection, when dealing with susceptible patients, can lead to early diagnosis and optimal treatment. CASE PRESENTATION: 37 M with history of chronic alcohol abuse, presented complaining of hemoptysis, SOB, subjective fever and generalized myalgias for 2 weeks. PE revealed tachypnea, fever and left lung crackles. Labs showed acute hypoxic respiratory failure and lactate elevation. CT revealed 9 x 6 cm inflammatory-appearing cavitary lung mass in the left lower lobe most likely representing a lung abscess, along with large left sided loculated pleural effusion. Patient was intubated and empiric antibiotic therapy was started.2 left CT were placed for loculated pleural effusion. Sputum and pleural fluid AFB were negative. Pleural fluid was exudative and revealed Gram positive cocci and Gram positive rods, with identification of sulfur granules which was highly suggestive of Actinomyces. Intrapleural fibrinolytic agents were given with optimal drainage of empyema. Patient was extubated and improved clinically DISCUSSION: Diagnosis of Pulmonary Actinomycosis, solely based on clinical presentation is not possible. Imaging studies commonly show air-space consolidation and/or cavitary or mass-like lesions. Parenchymal disease can also extend to pleural cavity and chest wall. BAL for culture is inappropriate since it may only represent colonization. Acceptable specimen include lung biopsy or pleural fluid. Gold-standard for diagnosing Actinomycosis is growth of the bacteria in culture, but is technically difficult and occurs only in a minority of cases. If the suspicion is high, the clinician should indicate this to the microbiologist to ensure appropriate processing specimen measures. Identification of sulfur granules from pleural fluid is strongly supportive of Actinomycosis and may be enough to lead the clinician into the diagnosis and appropriate management. Carbapenems or combination of a beta-lactam with beta-lactamase inhibitor in the setting of lung abscess, is a proper empiric approach.Therapy should be targeted once Actinomycosis has been diagnosed. Intravenous therapy should be given for 2 to 6 weeks, followed by oral route.Length of the oral antibiotic depends on clinical and radiological response. Resolution of radiographic findings may take several months, with 6 months to 1 yr. of oral antibiotics being recommended. CONCLUSIONS: Actinomycosis should be suspected in patients with history of aspiration or at risk for it and individuals with chronic alcohol abuse. A high clinical index of suspicion could lead to the proper usage of diagnostic tools and facilitate the rare growth of the causative pathogen in culture. Proper diagnosis should guide to targeted treatment and follow up, along with optimal duration of antibiotics. Reference #1: Choi J, Koh WJ, Kim TS, et al. Optimal duration of IV and oral antibiotics in the treatment of thoracic actinomycosis. Chest. 2005 Oct. 128(4):2211-7. Reference #2: De Montpreville VT, Nashashibi N, Dulmet EM. Actinomycosis and other bronchopulmonary infections with bacterial granules. Ann Diagn Pathol. 1999 Apr. 3(2):67-74. Reference #3: Kim TS, Han J, Koh WJ, et al. Thoracic Actinomycosis: CT Features with Histopathologic Correlation. AJR Am J Roentgenol. 2006 Jan. 186(1):225-31. DISCLOSURES: No relevant relationships by Jonathan Arnedo, source=Web Response No relevant relationships by Yesika Garcia, source=Web Response No relevant relationships by Seyedmohammad Pourshahid, source=Web Response No relevant relationships by Theo Trandafirescu, source=Web Response