Méningites et méningoencéphalites aseptiques

The etiologies of aseptic meningitis or meningoencephalitis can be classified in three main groups: (i) systemic diseases with meningeal involvement, which include sarcoidosis, Behcet's disease, Sjögren's syndrome, systemic lupus erythematosus, and Wegener's granulomatosis. In addition, cerebral venous thrombosis may be encountered during various systemic diseases, but also in any prothrombotic disorder; (ii) drug-induced aseptic meningitis, mostly reported with non-steroidal anti inflammatory drugs, antibiotics (sulfamides, penicillins), intravenous immunoglobulin, and monoclonal antibodies anti-CD3 (OKT3); (iii) neoplastic meningitis, either related to solid cancer metastasis (adenocarcinoma, melanoma) or malignant hemopathy with meningeal involvement (lymphoma, leukemia). Three other groups of meningitis are not stricto sensu aseptic, but should be included in the differential diagnosis: (i) infectious meningitis or menigoencephalitis related to difficult-to-diagnose pathogens, that require specific diagnostic investigations; (ii) bacterial meningitis or meningoencephalitis with negative cerebrospinal fluid microbiological findings due to previous antibiotic administration and (iii) parameningeal infections associated with meningeal reaction.