The meninges are a layer of protection for the brain which reduces the likelihood of damage to the brain during impact or injury. Meningitis is the infection and inflammation of the meninges, and also involving the cerebral cortex immediately adjacent to the meninges. The cortex is where all the functioning in the brain connects, so the inflammation can result in a reduction of all motor and sensory function throughout the body.

Bacterial meningitis is a general term for any of the bacteria that will cause meningitis. There are several different strains, the most prominent being meningococcus, listeria, and pneumococcus.

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The general clinical findings for bacterial meningitis are:

• Neck stiffness
• Fever
• Altered mental status/confusion
• Low glucose
• High protein
• Increased WBC
• Positive bacterial culture
• Predominance of PMNs (polymorphonuclear leukocytes) in spinal tap/LP
• Seizures (in late stages)
• Localized meningeal inflammation present on an MRI

Clinical findings for meningococcus are:

• Cough
• Sneezing
• Fever with chills (rigor)
• Petechial rash

Clinical findings for listeria are:

• Fever
• Vomiting
• Diarrhea
• Lethargy
• Difficulty breathing

Clinical findings for pneumococcus are:

• Fever with chills (rigor)
• Headache
• Nausea and vomiting
• Sensitivity to light
• Sleepiness
• High white blood cell count, predominantly polymorphonuclear leukocytes (PMNs)

Early diagnosis of any infection is critical, but in the case of bacterial meningitis it is especially vital due to the rapid progression of disease. It can be treated with a variety of antibiotics, such as Acyclovir, but the treatment must be initiated as quickly as possible.

Brain function

Understanding the brain

What is meningitis?

What are bacteria?

What is the central nervous system?

What is a lumbar puncture?