Understanding Infection of the Central Nervous System by Dr Winnie Lim Khoo, Neurologist

Infectious diseases that involve the nervous system affect millions of people around the world. They constitute the sixth cause of neurological consultation in primary care services and are reported globally by the World Heath Organization (WHO). Infections of the central nervous system affect the brain and spinal cord, usually causing swelling. The consequences of this can be serious but with rapid treatment most cases of central nervous system infection can resolve without long-term neurological damage.

Once inside the central nervous system, bacteria and viruses multiply, and the body responds by triggering inflammation and swelling:

1. Meningitis develops when a bacterium, virus, or fungus infects the meninges, the membranes that line the brain and spinal cord. Bacterial meningitis is generally more life-threatening than viral meningitis, but is not as infectious.
2. Encephalitis involves general swelling of the brain and is usually caused by a viral infection. Herpes simplex virus, which is the virus responsible for cold sores, and human herpes viruses, including the chicken pox and measles viruses, can live in the nerves for years after infection, before travelling to the brain and causing encephalitis. Other viruses can be spread by insect bites and include the West Nile fever virus and the Japanese encephalitis virus.
3. Brain abscesses can develop as a result of an infection with bacteria or fungi that spreads into the brain, causing a build up of pus that destroys healthy nerve cells.

It is advisable to visit a specialist or neurologist when one has infection of the nervous system.