B49-07 Atypical Presentation and Multiorgan Complications of Infective Endocarditis: A Diagnostic Challenge

Abstract Introduction Infective endocarditis (IE) presents with a wide clinical spectrum, ranging from classic features such as fever, new or changing murmurs, and embolic events, to atypical systemic manifestations including weight loss, anemia, and cytopenias that can mimic malignancy or autoimmune disease. Diagnosis relies on clinical suspicion supported by echocardiographic and microbiological evidence, yet delayed recognition remains common. Complications such as heart failure, embolic events, and renal impairment significantly contribute to morbidity and mortality. Early identification and multidisciplinary management are essential to improve outcomes in this challenging and often elusive condition. Case Presentation A 50-year-old previously healthy man presented with one week of generalized weakness and a 50-pound unintentional weight loss over three months. On admission, temperature 98.7 °F, blood pressure 118/70 mmHg, heart rate 92 bpm, and oxygen saturation 97% on room air. Physical examination revealed a petechial rash on lower extremities. Laboratory evaluation showed hemoglobin 8.1 g/dL, platelets 88,000/µL, white blood cell count 11.2 × 109/L, creatinine 2.4 mg/dL, mild hyperbilirubinemia, reticulocytosis, and a positive direct Coombs test. CT imaging of the abdomen demonstrated hepatosplenomegaly. Blood cultures grew Streptococcus viridans, and transesophageal echocardiography revealed mitral valve vegetations with severe regurgitation. Neurologic imaging, prompted by intermittent confusion, identified multiple acute infarcts and a mild subarachnoid hemorrhage consistent with septic emboli. Worsening renal function with positive proteinase-3 antibodies anti- neutrophil cytoplasmic antibodies (PR3-ANCA) led to renal biopsy, confirming post-infectious glomerulonephritis (PIGN). The patient was treated with targeted intravenous antibiotics and a short course of corticosteroids. Mitral valve surgery was deferred for two weeks post-stroke. He demonstrated significant clinical and renal recovery and was discharged in stable condition. Discussion This case illustrates the diagnostic challenge of infective endocarditis (IE) presenting atypically, without fever or new murmur, but with systemic findings including weight loss, cytopenias, and splenomegaly. Renal involvement in IE is recognized, yet biopsy-confirmed post-infectious glomerulonephritis (PIGN) is uncommon, reported in 6-20% of infection-associated glomerulonephritis cases. Positive PR3-ANCA further complicates differentiation from primary ANCA-associated vasculitis, making renal biopsy essential for accurate diagnosis and management. Septic embolic strokes from valvular vegetations are well documented, highlighting the need for prompt echocardiography in unexplained neurologic events. Current evidence supports deferring valve surgery for approximately two weeks after stroke to reduce perioperative bleeding risk. This case emphasizes the importance of considering IE in patients with unexplained systemic illness, cytopenias, or multi-organ dysfunction, and demonstrates how coordinated multidisciplinary care can improve clinical and renal outcomes. This abstract is funded by: none