A CASE OF PNEUMONIC TULAREMIA MIMICKING COVID-19

Abstract

TOPIC: Chest Infections TYPE: Medical Student/Resident Case Reports INTRODUCTION: Tularemia is a zoonotic infection caused by Francisella tularensis, an anaerobic and fastidious gram-negative bacterium. It is transmitted from direct inhalational exposure and bites from infected ticks, rabbits, rodents, birds, or domestic animals. About 200 cases of human tularemia are reported each year in the United States. We report an unusual case of tularemia without any known exposure with a recent Coronavirus disease-19 (COVID-19) infection with an overlap of symptoms of COVID-19 pneumonia. CASE PRESENTATION: A healthy 22 years old male with an uncomplicated COVID-19 infection a month ago presented with fever, nausea, vomiting for a week and a resolving inguinal rash with no recent travel, sick contacts, occupational or animal exposures. On admission, he was febrile up to 103.4, tachycardiac and tachypneic with coarse breath sounds in bilateral lungs, right cervical adenopathy without any rash or erythema on the skin. His initial labs were WBC 16.6 k/mcl, platelets 154 k/mcl, elevated inflammatory markers (ESR 64mm/hr, CRP 164mg/ml), mild transaminitis (AST/ALT 43/89 uL), negative COVID-19 PCR, initial troponin of 1.6 which peaked to 3.6 and a procalcitonin 12.6. An electrocardiogram showed sinus tachycardia, a chest x-ray and computed tomography (CT) of the chest showed bilateral basilar heterogenous opacities, echocardiography showed regional wall motion abnormalities with preserved ejection fraction and right internal jugular vein thrombosis on the upper extremity doppler ultrasound. On hospital day 2, he developed acute hypoxic respiratory failure and septic shock requiring mechanical ventilation. Initial differential diagnosis was concerning for acute viral illness, viral myocarditis, murine typhus, bacterial pneumonia, and COVID-19 inflammatory syndrome. A complete viral and autoimmune workup was negative except for a positive Francisella tularemia antibody. He completed 10 days of oral doxycycline and was discharged home on room air on three months of rivaroxaban. DISCUSSION: Pneumonic tularemia presents with initial non-specific symptoms followed by fever, chest pain, productive cough with nodular infiltrates with pleural effusion on imaging, it can be challenging to diagnose with overlapping symptoms with COVID-19. In our case, the initial history and imaging findings could have been consistent with viral myocarditis and post COVID-19 hypoxia.Yet, the ability to wean off oxygen and the rapid improvement in symptoms with initial treatment without steroids was more consistent with some other viral or bacterial etiology of disease. CONCLUSIONS: COVID-19 is associated with superimposed bacterial and fungal infections. Limited data is available on the covid-19 inflammatory syndrome with superimposed zoonotic infections. However, clinicians must be vigilant of other febrile illnesses and alternative diagnoses whose symptoms overlap with COVID-19. REFERENCE #1: Patel HM. Murine typhus mistaken for COVID-19 in a young man. BMJ Case Rep. 2020;13(11):e239471. Published 2020 Nov 3. doi:10.1136/bcr-2020-239471 REFERENCE #2: Siberry GK. Keeping Your Diagnostic Mind Open During the COVID-19 Pandemic. Pediatr Infect Dis J. 2020 Dec;39(12):e444. doi: 10.1097/INF.0000000000002951. PMID: 33214407. REFERENCE #3: Gurcan S. Epidemiology of tularemia. Balkan Med J. 2014;31(1):3-10. doi:10.5152/balkanmedj.2014.13117 DISCLOSURES: No relevant relationships by Christopher Dayton, source=Web Response No relevant relationships by Mahnoor Mir, source=Web Response