Title : Diagnostic and therapeutic challenges in infectious diseases: A rare case of bacterial endocarditis and glomerulonephritis without pathogen detection
Abstract:
Background: Infective endocarditis (IE) is a life-threatening infectious condition with a high global morbidity and mortality rate1. The global incidence of IE reaches 13.8 cases per 100,000 population annually, with an estimated 66,300 deaths2. Approximately 10% of all IE cases are classified as Blood Culture- Negative Infective Endocarditis (BCNIE), where the causative bacteria cannot be identified3. The absence of specific bacterial identification complicates diagnosis and delays appropriate therapy, increasing the mortality rate among BCNIE patients4,5. This case report aims to explore the diagnostic criteria for IE despite unclear culture results and discuss therapeutic management to improve the quality of life for patients with BCNIE.
Case Ilustration: A 30-year-old male presented with worsening shortness of breath over a week, primarily during physical activity. The symptom had persisted for four months, accompanied by swelling of the legs and abdomen. The patient reported high fever with chills and red rashes on the hands and feet for five days. Echocardiography revealed severe aortic regurgitation with vegetation. Blood cultures were negative for any organisms. IE was diagnosed based on the Modified Duke Criteria. Empiric antibiotic therapy was administered for 14 days alongside supportive management. After two weeks of treatment, the patient was afebrile, with resolved rashes and reduced abdominal swelling, although intermittent shortness of breath persisted. A follow-up echocardiography after therapy showed worsening aortic valve vegetation despite the patient’s stable clinical condition.
Discussion: IE is prevalent in developing countries, with a mortality rate of 6% when promptly diagnosed and treated, but reaching 100% in untreated cases. In Indonesia, the prevalence of IE remains unclear due to limited diagnostic facilities, especially for BCNIE6. In this patient, definitive IE diagnosed using Modified Duke Criteria with one major criteria (vegetation on the aortic valve) and three minor criteria (fever, petechiae, and glomerulonephritis were identified. Despite blood culture negativity, empiric antibiotic therapy following guidelines—ampicillin-sulbactam and gentamicin—was provided for 14 days1. In addition to targeted immunological therapy with methylprednisolone, the patient received supportive care, including fluid management, PRC and albumin transfusions, as well as heart failure treatments such as furosemide, spironolactone, and lisinopril7. After 15 days of hospitalization, the patient’s condition stabilized, but follow-up echocardiography revealed increased vegetation on the aortic valve, suggesting an inadequate response to empiric therapy3. Repeat blood cultures are planned to confirm the causative pathogen, and further research is required to evaluate therapeutic effectiveness.
Conclusion: Infective endocarditis (IE) is a critical condition with significant diagnostic difficulties, particularly in BCNIE. The absence of positive blood cultures complicates therapy selection, and empiric antibiotics aligned with local antimicrobial patterns may fail to eradicate the causative pathogen. Accurate and specific diagnostic methods are critical for optimizing BCNIE management. Supportive therapy and targeted management of autoimmune manifestations can alleviate symptoms and enhance patients’ quality of life.
