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Updated: Jan 21, 2026
Aseptic Laboratory Techniques: Plating Methods
Published on: May 11, 2012
Aseptic meningitis
P Tattevin1, S Tchamgoué2, A Belem1
1Service de maladies infectieuses et réanimation médicale, CHU de Pontchaillou, rue Le Guilloux, 35033 Rennes Cedex, France.
Abstract:
Aseptic meningitis is defined as meningeal inflammation - i.e. cerebrospinal fluid (CSF) pleocytosis≥5 cells/mm3 - not related to an infectious process. Etiologies of aseptic meningitis can be classified in three main groups: (i) systemic diseases with meningeal involvement, which include sarcoidosis, Behçet's disease, Sjögren's syndrome, systemic lupus erythematosus and granulomatosis with polyangiitis; (ii) drug-induced aseptic meningitis, mostly reported with non-steroidal anti-inflammatory drugs (NSAIDs), antibiotics (sulfamides, penicillins), intravenous immunoglobulin, and monoclonal antibodies; (iii) neoplastic meningitis, either related to solid cancer metastasis (breast cancer, lung cancer, melanoma) or malignant hemopathy (lymphoma, leukemia). Most series in the literature included groups of meningitis that are not stricto sensu aseptic, but should rather be included in the differential diagnosis: (i) infectious meningitis related to virus, parasites, fungi, or fastidious bacteria that require specific diagnostic investigations; (ii) bacterial meningitis with sterile CSF due to previous antibiotic administration, and (iii) parameningeal infections associated with meningeal reaction. Despite progress in microbiological diagnosis (including PCR, and next generation sequencing), and identification of a growing panel of autoimmune or paraneoplastic neurological syndromes, up to two thirds of aseptic meningitis cases are of unknown etiology, finally labeled as 'idiopathic'. Description of new entities, such as the syndrome of transient headache and neurologic deficits with cerebrospinal fluid lymphocytosis (HaNDL) may decrease the proportion of idiopathic aseptic meningitis. This state-of-the-art review summarizes the characteristics of main causes of aseptic meningitis.
Insights
Aseptic meningitis involves inflammation of the meninges without infection. Causes include systemic diseases, drugs, and cancer, but many cases remain idiopathic.
Area of Science:
- Neurology
- Immunology
- Infectious Diseases
Background:
- Aseptic meningitis is defined by meningeal inflammation (CSF pleocytosis ≥5 cells/mm³) not caused by infection.
- Etiologies encompass systemic diseases (sarcoidosis, lupus), drug-induced reactions (NSAIDs, antibiotics), and neoplastic meningitis (cancers, lymphomas).
- Distinguishing aseptic meningitis from infectious causes and parameningeal infections is crucial for diagnosis.
Purpose of the Study:
- To review the main causes and characteristics of aseptic meningitis.
- To highlight the challenges in diagnosing aseptic meningitis, including differentiating it from infectious etiologies.
- To discuss the proportion of idiopathic cases and the impact of newly identified syndromes like HaNDL.
Main Methods:
- Literature review of aseptic meningitis etiologies.
- Classification of causes into systemic diseases, drug-induced, and neoplastic categories.
- Discussion of differential diagnoses, including infectious meningitis and parameningeal infections.
Main Results:
- Systemic diseases, drugs, and neoplasms are primary causes of aseptic meningitis.
- A significant proportion, up to two-thirds, of aseptic meningitis cases are labeled idiopathic.
- Advances in diagnostics like PCR and NGS aid in identifying causes, yet many remain unknown.
Conclusions:
- Aseptic meningitis has diverse etiologies requiring careful differential diagnosis.
- Many cases remain idiopathic despite diagnostic advancements, underscoring the need for further research.
- Recognition of specific syndromes may reduce the 'idiopathic' classification rate.
