A Sheep in Wolf's Clothing: Actinomyces Infection Imitating Malignancy

Document Type

Conference Proceeding

Publication Date

10-2024

Publication Title

Chest

Abstract

INTRODUCTION: Actinomyces infections, though infrequent, can present with clinical manifestations mimicking malignant neoplasms, posing diagnostic challenges for clinicians. CASE PRESENTATION: We present the case of a 52-year-old female with a past medical history including mood disorder, asthma/COPD (FEV1 24%), pulmonary hypertension, scleroderma on Cellcept, gastroesophageal reflux disease (GERD) with achalasia, and hypertension, who presented to the emergency department with complaints of hemoptysis. The patient reported multiple hospital visits over the past two weeks, initially presenting with upper respiratory tract infection (URI) symptoms and subsequently diagnosed with respiratory syncytial virus (RSV). She was admitted for COPD exacerbation and received treatment with steroids and intravenous antibiotics, later switched to Augmentin for a total of 2 weeks. Following discharge, the patient experienced worsening shortness of breath, increasing oxygen requirement, subjective fevers and some night sweats and multiple episodes of hemoptysis, which led to presentation at our ED. Labs showed WBC 15.6k w/ neutrophil predominance, Hgb 11.6, PLT 389, BMP grossly unremarkable, BNP 58, trop normal, COVID/flu/RSV negative, procal < 0.02. X-ray done in the ED showing bilobed 8.5 x 4.3 cm masslike opacity mid to upper zone of left lung. CT scan from previous hospital revealed masslike opacity in the ventral aspect of the left upper lobe: 3.4 x 3.6 x 4.2 cm with central necrotic/cavitary component and consolidation at the lung parenchyma distal to the presumed mass. Initial diagnoses were suspected to be malignancy, TB, bacterial and fungal pneumonia with immunosupressed status secondary to Scleroderma treatment. Extensive blood infectious workup was unremarkable, Bronchoscopy was performed with BAL of respiratory cultures yielding Actinomyces Odontolyticus and BAL was unremarkable on cytology. Unfortunately the mass could not be accessed on bronchoscopy. Per ID and Pulmonology recommendations, CT guided biopsy was deferred to outpatient. Patient was initially started on Zosyn in the ED and transitioned to Unasyn inpatient, and discharged with a prolonged course of Augmentin for 6-12 months per ID recommendations with plan to repeat CT chest within 6 weeks. On follow up and repeat imaging patient was found to have a significant reduction in lung mass to 2.5 x 1.0 cm along with improvement in symptoms. DISCUSSION: Although the incidence of pulmonary actinomycosis (PA) has notably decreased, diagnosing PA poses a significant challenge, often leading to delays of up to months. PA typically presents as nodules, consolidation, or masses, frequently mistaken for lung cancer, lung abscess, or tuberculosis due to overlapping radiological features. Given the nonspecific laboratory and clinical findings, distinguishing PA from lung malignancy remains challenging, with physicians commonly initially suspecting lung cancer. Key symptoms of PA include fever, chest pain, hemoptysis, dyspnea, and productive cough. Notably, the severity of PA symptoms has decreased alongside improvements in oral hygiene and the availability of effective antibiotics. CONCLUSIONS: Actinomyces infection should be considered in patients presenting with lung masses, particularly in those with a history of recent respiratory infections.

Volume

166

Issue

4 Suppl

First Page

A1540

Comments

Chest Annual Meeting, October 6-9, 2024, Boston, MA

DOI

10.1016/j.chest.2024.06.977

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