Severe Invasive Pneumococcal Disease in Two Siblings: Austrian Syndrome and Infected Aortic Aneurysm

Background: Invasive pneumococcal disease (IPD) is a severe form of Streptococcus pneumoniae infection, defined by its isolation from a normally sterile site (such as blood or cerebrospinal fluid (CSF)), and carries high mortality (approximately 20% in adults, rising to 30–40% in the elderly), particularly with multiorgan involvement. Its rarer forms include endocarditis, aortitis, infected aneurysms and Austrian syndrome (the triad of pneumonia, meningitis and endocarditis). Case Presentation: We describe two cohabitating brothers, unvaccinated against pneumococcus, both smokers and with alcohol use disorder, admitted to the hospital two weeks apart. The first patient, aged 53, presented with pneumonia, meningitis/ventriculitis and aortitis progressing to infected aortic aneurysms, requiring two operations and prolonged antibiotic therapy. S. pneumoniae was isolated from blood cultures and CSF S. pneumoniae real-time polymerase chain reaction (rt-PCR) was positive. The second patient, aged 48, presented with pneumonia, meningitis and aortic valve endocarditis (Austrian syndrome), requiring valve replacement. CSF was also rt-PCR positive for S. pneumoniae and blood cultures grew S. pneumoniae. An immunodeficiency work-up was normal in both brothers. Conclusions: These cases illustrate the rare, near-simultaneous occurrence of severe IPD in cohabiting siblings and the complexity of its cardiovascular and neurological complications, underlining the importance of early diagnosis, a multidisciplinary approach and pneumococcal vaccination of at-risk groups; when severe disease occurs without classic risk factors, an underlying immunodeficiency should be excluded.