Significantly Elevated Rheumatoid Factor in a Patient with Infective Endocarditis: A Case Report and Literature Review

Nazish Malik^1, , David Kelley¹ and Samir Dalvi¹

¹Department of Rheumatology and Immunology, University of Arkansas for Medical Sciences, Little Rock, AR

Cite this paper:
Nazish Malik, David Kelley and Samir Dalvi. Significantly Elevated Rheumatoid Factor in a Patient with Infective Endocarditis: A Case Report and Literature Review. American Journal of Medical Case Reports. 2025; 13(6):34-36. doi: 10.12691/ajmcr-13-6-2

Abstract

A 49-year-old male with unremarkable history presented with six months of dry cough, migratory pain in the lower extremity joints, intermittent fever, and unintentional weight loss. He had partial relief from initial steroid therapy but continued to have symptoms. Physical Examination showed a systolic murmur and moderate swelling of the right ankle. On lab work up, The ESR was elevated to 64 mm/hr, the rheumatoid factor was 368 IU/mL, serum ferritin was 570 ng/mL, while the ANA was positive at 1:640 speckled pattern. Blood cultures grew Streptococcus Mutans suggestive of infective endocarditis. Echocardiogram revealed a bicuspid aortic valve with moderate aortic stenosis, mild aortic regurgitation, and an oscillating echo density on the aortic valve suggestive of vegetative growth. The patient was treated with oral Linezolid (600 mg BID) despite initial refusal of hospitalization and referred for cardiology follow-up. He underwent aortic and mitral valve replacement without postoperative complications. This case raises awareness of the importance of considering infective endocarditis in the differential diagnosis of patients presenting with systemic inflammatory symptoms and positive rheumatologic work up.

Keywords:
Infective Endocarditis Rheumatoid Factor S. Mutans Linezolid

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