RESUMO
It is important not to miss a diagnosis of infective endocarditis. It is fatal if untreated and most often successfully treatable if recognized. We report a classic case of subacute bacterial endocarditis with Osler nodes and Janeway lesions due to viridans streptococci from an oral source of poor dentition, infecting a presumably abnormal mitral valve. The diagnosis was missed repeatedly by multiple different clinicians over the course of seven months. Detailed analysis of this case suggests some of the pitfalls that led to the delay in diagnosis. The infective endocarditis was masked by analgesic medication, inadequate physical examination, and narrow focus thinking. The images of this case can serve as a reminder of the features of infective endocarditis. The detailed history and discussion can provide potential lessons in how to not miss the diagnosis of infective endocarditis.