B49-02 Polymicrobial Bacteremia Without Endocarditis Leading to Pulmonary Mycotic Aneurysm and Hemoptysis

Abstract Introduction Pulmonary mycotic aneurysms are rare but potentially fatal complications of bloodstream infections, often resulting from septic emboli or direct vascular seeding. While classically leading to endocarditis or a single virulent organism, they can also develop in the setting of polymicrobial bacteremia without an identifiable primary focus. Recommendation requires vigilance, as rupture can be catastrophic. Case presentation A 38-year-old man with hypertension, gout and remote history of Wilms tumor status post right nephrectomy presented with fevers and chills for 1 week. He was initially treated for presumed Lyme disease without improvement. On admission, lab testing revealed leukocytosis and markedly elevated procalcitonin. Blood cultures repeatedly grew multiple organisms including Streptococcus mitis, Streptococcus salivarius, lactobacillus, Veillonella, Prevotella, Granulicatella, Saccharomyces, and Staphylococcus epidermidis, consistent with polymicrobial bacteremia. Both transthoracic and transesophageal echocardiograms showed no valvular vegetations. Serial CT imaging demonstrated evolving bilateral cavitary pulmonary nodules. With broad spectrum antibiotic therapy (meropenem, vancomycin, gentamicin and amphotericin B), blood cultures cleared but he remained intermittently febrile and hypoxic. Gastrointestinal and dental evaluations failed to reveal a clear source, and bone marrow biopsy was unremarkable.10 days after his culture cleared, he developed massive hemoptysis (180 mL of bright red blood). CT angiography revealed a new right-sided subsegmental pulmonary emboli and right middle lobe pulmonary artery pseudoaneurysm adjacent to a cavitary lesion, findings consistent with pulmonary mycotic aneurysm. He underwent successful endovascular embolization, resulting in complete cessation of bleeding and subsequent stabilization. Discussion This case illustrates a rare incidence of pulmonary mycotic aneurysm secondary to polymicrobial bacteremia in the absence of endocarditis. This diverse flora, largely comprising oral and enteric organisms, suggested mucosal translocation as a potential mechanism, though no anatomic breach was identified. Persistent fevers, cavitary lesions, and hemoptysis in a patient with ongoing bacteremia, even without endocarditis she has raised suspicion for vascular complications. Early recognition and endovascular management are critical to prevent rupture and mortality. Conclusion Polymicrobial bacteremia without endocarditis can lead to septic emboli and mycotic aneurysm formation. Clinicians should maintain a high index of suspicion for this life-threatening complication when faced with persistent bacteremia and cavitary pulmonary lesions unresponsive to antibiotics. This abstract is funded by: None