Meningitis is infection of the meninges, most frequently due to hematogenous spread of a bacterial infection.

Some people with the infection die and death can occur in as little as a few hours. However, most people recover from bacterial meningitis. Those who do recover can have permanent disabilities.

Patients often present with fever, meningism (headache, nuchal rigidity and photophobia) and altered state of consciousness.

Diagnosis is based on clinical and laboratory (lumbar puncture) findings.

Imaging helps to exclude other causes, helps to confirm the diagnostic hypothesis and helps to exclude complication (empyema, parenchymal abscess, ventriculitis, hydrocephalus). Sometimes meningitis is due the direct spread of infection from paranasal sinus or mastoid infection, thus imaging helps exclude this source of infection.

Brain CT may be negative or may show effacement of some sulci. Leptomeningeal enhancement is better seen in post-contrast FLAIR images are very helpful to show leptomeningeal enhancement.

Case courtesy of Dr. Francesca Graziani