What is a Central Nervous System Infection

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Types of Central Nervous System Infections

A central nervous system infection can be classified as viral, bacterial, fungal, or protozoal. These infections either affect the brain directly, or through the membrane, or meninges, which covers the brain and spinal cord. The invading organism responsible for the infection is present in the cerebrospinal fluid.

One type of bacterial infection is neurosyphilis. It affects the brain and spinal cord. Neurosyphilis develops from untreated syphilis, which is caused by the bacteria Treponema pallidum. Bacterial meningitis is another bacterial infection that affects the central nervous system. Haemophilus influenzae type b (Hib), Neisseria meningitidis, and Streptococcus pneumoniae are three bacterial strains that cause bacterial meningitis. The bacteria inflames and swells the meninges.

West Nile encephalitis is a viral infection that affects the brain. The brain becomes inflamed by the West Nile virus. The virus is usually transmitted through mosquito bites.

Cryptococcal meningitis is a fungal infection that affects the meninges. It is caused by the fungus Cryptococcus neoformans. This infection usually afflicts individuals with a weaken immune system.

A central nervous system infection caused by a protozoa is Toxoplasmosis. It is caused by the protozoan Toxoplasma gondii. The parasite causes inflammation of the brain.


The common symptoms of a central nervous system infection include fever, stiff neck, headaches, and confusion. The symptoms usually arise quickly for bacterial meningitis, while the symptoms of cryptococcal meningitis become apparent over several days to a few weeks. The onset of neurosyphilis occurs at least 10 years after the initial infection, and its symptoms are more serious. Blindness, dementia, and an abnormal walk are symptoms of neurosyphilis.


Infections of the central nervous system usually leave signs in the cerebrospinal fluid. Bacterial and Cryptococcal meningitis is usually diagnosed by testing the cerebrospinal fluid. West Nile encephalitis can be diagnosed with a blood test or by testing the cerebrospinal fluid.


Viral infections that affect the central nervous system are very hard to treat. A combination of anti-inflammatory drugs and intravenous fluids are used to help the body fight off the infection. Some antiviral drugs are available for certain viral infections. For example, Aciclovir is somewhat effective against Herpesviral Encephalitis.

Bacterial infections are usually treated with antibiotics. Antibiotics are also used to treat the protozoal infection Toxoplasmosis. Fungal infections such as Cryptococcal meningitis are treated with antifungal medications.


If an infection of the central nervous system isn’t treated properly, serious problems may arise. Advanced bacterial meningitis causes brain damage, coma, and even death. Hearing loss and seizures are possible with the progression of Cryptococcal meningitis. Long term effects of West Nile encephalitis include memory loss, irritability, depression, and confusion.


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