高齢者における髄膜炎菌性疾患：診断と管理における課題

Invasive meningococcal disease (IMD) in older adults frequently presents with atypical clinical manifestations, including bacteremic pneumonia, often without classical meningeal signs or sepsis, which presents clinicians with diagnostic challenges, and may delay treatment, which contributes to the high mortality observed in older adults. Within the broader resurgence of IMD observed since relaxation of quarantine measures introduced to mitigate the impact of the COVID-19 pandemic, there has been a notable increase in reporting of such atypical cases. The aim of this review is to summarize epidemiological, diagnostic, and treatment aspects of non-meningeal forms of IMD in older patients, with a focus on meningococcal pneumonia. By convention, laboratory confirmation requires N. meningitidis detection by culture, polymerase chain reaction (PCR), or antigen detection. In most cases, presentation of meningococcal pneumonia is similar to that of other forms of community-acquired pneumonia, and cerebrospinal fluid sampling may be non-informative. This places a premium on early blood culture for N. meningitidis, allied with testing of respiratory samples (e.g., broncho-alveolar washes). Many cases are linked to isolates of serogroups Y and W. When confirmed, treatment with third-generation cephalosporins is generally preferred. Chemoprophylaxis and vaccination of close contacts is essential for controlling onward meningococcal disease transmission and prevention of further cases.