Infective endocarditis caused by Streptococcus pneumoniae from sinusitis: A case report

Since the advent of the pneumococcal vaccine, cases of infective endocarditis (IE) from Streptococcus pneumoniae have become rare. Pneumococcal endocarditis (PE) may be the initial presentation in Austrian syndrome, which is very lethal. PE needs early detection and treatment and more commonly develops from pneumonia. To our knowledge, this is the first report of PE caused by sinusitis after pneumococcal vaccination. Here, a 71-year-old male presented with low back pain and right ankle joint pain. He had no dental history or pneumonia and received a pneumococcal vaccine 2 years prior. Blood tests showed high inflammatory response. We suspected IE due to the high inflammatory response and oligoarthritis. Transthoracic echocardiography showed vegetation at the aortic valve. As IE was probable, empiric antibiotic therapy was promptly initiated. Blood cultures detected S. pneumoniae. IE was diagnosed based on Duke's diagnostic criteria. After starting antibiotic treatment, lumbar magnetic resonance imaging (MRI) showed an abscess in the right erector spinae. Cranial MRI showed bilateral maxillary sinusitis. Sinusitis was considered the possible initial focus of infection. IE should be considered a differential in patients with S. pneumoniae detected in blood cultures without pneumonia even after pneumococcal vaccination as PE sometimes follows a fatal course.