Table 1_Q fever endocarditis complicating biventricular failure: diagnostic and therapeutic insights from a case report and literature review.docx

BackgroundQ fever endocarditis (QFE) is a rare, life-threatening infection caused by Coxiella burnetii, accounts for 5–6% of culture-negative endocarditis cases and predominantly affects prosthetic or structurally abnormal valves. Diagnosis is frequently delayed by negative blood cultures and subtle or atypical echocardiographic findings.
Case presentationWe describe a 45-year-old man with dual mechanical valves and ischemic cardiomyopathy who presented in cardiogenic shock with acute decompensated heart failure and cardiogenic shock. Transesophageal echocardiography revealed severe prosthetic mitral valve dehiscence with paravalvular regurgitation. Despite broad empiric antimicrobial therapy, blood cultures remained negative until serologic testing confirmed QFE. His clinical course was complicated by severe biventricular failure, recurrent infections, and refractory fluid overload, requiring continuous renal replacement therapy, prolonged doxycycline–hydroxychloroquine therapy, and intensive multidisciplinary care. Surgical intervention was deferred because of prohibitive operative risk, and the patient ultimately died from multiorgan failure.
Literature reviewA scoping review of 53 studies, comprising 421 cases on QFE found that patients were predominantly male (77.4%), with a weighted mean age of 53 years. Aortic valve involvement was most frequently reported (57.5% of cases with available valve data), and vegetations were described in 65.1% of cases with reported echocardiographic findings. Blood cultures were negative in 96.2% of cases with available culture data, while Phase I IgG titers ≥1:800 were reported in 83.7% of cases with available serologic data. Doxycycline plus hydroxychloroquine was the most commonly used treatment regimen (52.2%), and cardiac surgery was performed in 58.4% of cases with available surgical data. Reported mortality was 10.6% among cases with available outcome data.
ConclusionThis case highlights the diagnostic challenges of QFE in patients with prosthetic valves and underscores the importance of early serologic testing in the setting of culture-negative endocarditis. The accompanying literature synthesis confirms the central role of serology, the frequent need for surgical intervention, and the persistent challenges in achieving definitive cure.