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MSU College of Osteopathic Medicine

I. General Principles

A. Inflammation vs Infection: 

Inflammation is not synonymous with infection. The body responds to an insult with inflammation; if an infectious agent is present, inflammation is accompanied by infection. The subject of this unit is the response of the nervous system to infectious agents.

B. Routes of Infection

Although the brain is well protected by coverings (meninges) and the blood brain barrier, these are not absolute barriers. Routes of infection include:

  • Hematogenous Spread: blood-borne spread from a primary source of infection, often the lung
  • Direct Implantation: infection as the result of trauma or surgery
  • Local extension: infection from nearby site of suppura­tion
  • Spread of viruses from PNS along nerves: A few viruses can spread along peripheral nerves to reach the central nervous system