Aseptic meningitis

Case contributed by Bruno Di Muzio


Headache, diplopia and ataxia.

Patient Data

Age: 40 years
Gender: Female

CT Brain


No acute intracranial hemorrhage. Cortical volume is age-appropriate. No hydrocephalus. No CT evidence of evolving infarct. The basal cisterns are unremarkable. The paranasal sinuses and mastoid air cells are clear. No suspicious osseous lesion. 


Normal exam. 

The patient was submitted to a lumbar punction: 


  • Erythrocytes 0
  • Polymorphonuclear cells 0
  • Lymphocytes 140


No organisms seen


  • CSF Protein 0.90 H g/L (normal range 0.15-0.45)
  • CSF Glucose 2.8 mmol/L (normal range 2.5-5.0)

MRI Brain


Extensive leptomeningeal enhancement most conspicuous on post contrast axial FLAIR imaging is evident within the sulci of the frontal, parietal sulci, cerebellar folia and anterior to the medulla.

No intra or extra axial mass, hemorrhage or collection. No parenchymal signal abnormality evident. No diffusion restriction to suggest recent infarction. Normal appearance of mid-sagittal structures.

No evidence of hydrocephalus.

The dural venous sinuses remain patent with no evidence of venous sinus occlusion or thrombosis.

Conclusion: Extensive supra and infratentorial leptomeningeal enhancement consistent with meningitis of multiple etiologies with infective (including atypical organisms such as TB and cryptococcus), inflammatory (neurosarcoid) and hematological malignancies. Correlation with CSF is recommended.

No parenchymal disease or dural venous sinus thrombosis.​

Case Discussion

The CSF culture revealed no growth of microorganisms. The case was handled as aseptic meningitis, which basically corresponds to an inflammation of the brain meninges not caused by pus-producing bacteria. Causes of this type of meningitis are viruses and non-infectious conditions such as systemic lupus erythematosus, lymphoma, leukemia, and NSAIDs and other drugs. 

Enteroviruses infection is considered the main cause, particularly during summer and autumn 1

It is important to note how the addition of a post-contrast FLAIR sequence helped in spotting the meningeal enhancement. MRI protocols for brain infection or leptomeningeal diseases can be benefited from this acquisition. 

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