A52-23 Boy Meets Wolf: A Case of Legionella in Lupus

Abstract Introduction Immunosuppressants used to treat autoimmune disease increase the risk of infection, including community acquired pneumonia (CAP). Here we describe an atypical presentation of a patient with a systemic lupus erythematosus (SLE) flare who presented with acute respiratory distress syndrome (ARDS), acute renal failure (ARF), elevated transaminases, pneumothorax (PTX), and sudden onset heart failure. Case A 29-year-old man with SLE presented for 1 week of chest pain and shortness of breath. He was halfway through a 4-week steroid taper for cutaneous lupus flare. Upon presentation to the emergency department, vitals included hypoxia to 60%, respiratory rate of 55, fever of 100.4 F, blood pressure of 90/60, and heart rate of 170. Labs were notable for respiratory acidosis, low complement, and hyperkalemia. Initial CT chest showed bilateral multifocal consolidations with small punctate cavitations. He was intubated, and started on broad-spectrum antibiotics, IV methylprednisolone for ARDS, and continuous renal replacement therapy (CRRT) for ARF from suspected acute tubular necrosis vs lupus nephritis. All steroid sparing immunosuppressants were held. He was transferred to the intensive care unit (ICU) and underwent bronchoscopy with concern for possible escalation to veno-veno extracorporeal membrane oxygenation. His urine Legionella antigen was positive and bronchial alveolar lavage culture grew Legionella pneumophila. On transthoracic echo, he was found to have biventricular failure consistent with Takotsubo cardiomyopathy and ejection fracture of 20% that eventually improved to 40%. As he continued treatment for Legionella, he developed subcutaneous right (R) chest wall emphysema. No R lung sliding was seen on ultrasound. Subsequently, a chest tube was placed. Repeat CT chest revealed enlarging cavitary lesions, R PTX, and pneumomediastinum. The enlargement of cavitary lesions was attributed to resolving Legionella with low suspicion for lymphangioleiomyomatosis. After a 2-week course of Azithromycin, the patient’s respiratory and mental status improved and he was extubated to room air. Throughout hospitalization, he had elevated transaminases with benign ultrasound and MRI/MRCP. Liver biopsy revealed neutrophilic infiltrates consistent with resolving infection. He was discharged home. Discussion While Legionella causes only 6% of CAP, approximately 20-30% of CAP requiring ICU admission is due to Legionnaire pneumonia. Here we describe an atypical presentation with initial mild punctate cavitations, no hyponatremia, and low-grade fever, but rapid deterioration to multi-organ failure. This case emphasizes the importance of rapid Legionella diagnosis with urine Legionella antigen testing (specificity 100%, sensitivity 75%) in patients with concurrent autoimmune flare and infectious disease. This abstract is funded by: None