A49-15 A Burning Lung, an Angry Heart: Legionella Presenting as Myocarditis

Abstract Introduction Legionella pneumophila is a gram-negative bacterium often found in freshwater environments, commonly associated with severe atypical pneumonia. While pulmonary manifestations are well described, cardiac involvement is rare and severely affects prognosis. We present a rare case of legionella myocarditis complicated by refractory cardiogenic shock and an unfortunate outcome despite maximal intervention. Case Report A previously healthy 52-year-old man presented with one week of progressive shortness of breath, diarrhea, fevers, chest discomfort and lethargy. He was febrile on admission (38.5C) and in acute hypoxic respiratory failure, initially requiring oxygen supplementation, and quickly evolving to respiratory distress escalating to endotracheal intubation. While initial cardiac examination was unremarkable, lung auscultation revealed bilateral rhonchi and rales. Laboratory findings showed elevated white blood cell count to 22.80 ×109/L, hyponatremia to 128 mmol/L, markedly elevated creatine kinase (2710 U/L), brain natriuretic peptide 469 pg/mL, and high-sensitivity troponin peaking at 12,960 ng/L. Legionella urinary antigen was positive. Electrocardiography revealed ST segment depressions on the anterior leads. Chest X-ray demonstrated bilateral infiltrates and chest CT angiography confirmed the pneumonia and excluded pulmonary embolism. Transthoracic echocardiography revealed severely reduced ejection fraction of 20%. The acute laboratory findings and the echo results supported acute myocarditis. The patient was diagnosed with severe Legionella pneumonia complicated by fulminant myocarditis and acute heart failure, for which empiric antibiotic therapy with azithromycin, cefepime, and vancomycin was initiated. Clinical course was complicated by ventricular fibrillation arrest requiring prolonged resuscitation for return of spontaneous circulation. Post-arrest care required multiple vasopressors for blood pressure support, as well as initiation of venoarterial extracorporeal membrane oxygenation (ECMO) along with intra-aortic balloon pump placement. Despite aggressive interventions, clinical status continued to deteriorate with multiorgan failure. Care was transitioned into comfort measures, and the patient expired shortly thereafter. Discussion Although rare in legionella pneumonia, cardiac involvement can be severe and life threatening. This case highlights the devastating sequalae of legionella myocarditis which may present with elevated cardiac biomarkers, new ventricular dysfunction, and rapid hemodynamic instability. Therefore, clinicians must be aware of possible life-threatening cardiac complications of legionella pneumonia, as early suspicion, supported by echocardiography and laboratory findings might prompt early initiation of cardiac support. Review of the literature shows that some reported cases of legionella myocarditis fully recover with antibiotic therapy, while others quickly deteriorate as described here. Nonetheless, prognosis largely depends on the timing of care and severity at presentation. This abstract is funded by: None