neuronitis

Neuroinflammation is inflammation of the nervous tissue. It may be initiated in response to a variety of cues, including infection, traumatic brain injury, toxic metabolites, or autoimmunity. In the central nervous system (CNS), including the brain and spinal cord, microglia are the resident innate immune cells that are activated in response to these cues. The CNS is typically an immunologically privileged site because peripheral immune cells are generally blocked by the blood–brain barrier (BBB), a specialized structure composed of astrocytes and endothelial cells. However, circulating peripheral immune cells may surpass a compromised BBB and encounter neurons and glial cells expressing major histocompatibility complex molecules, perpetuating the immune response. Although the response is initiated to protect the central nervous system from the infectious agent, the effect may be toxic and widespread inflammation as well as further migration of leukocytes through the blood–brain barrier may occur.

== Causes == Neuroinflammation is widely regarded as chronic—as opposed to acute—inflammation of the central nervous system. Acute inflammation usually follows injury to the central nervous system immediately, and is characterized by inflammatory molecules, endothelial cell activation, platelet deposition, and tissue edema. Chronic inflammation is the sustained activation of glial cells and recruitment of other immune cells into the brain. Chronic inflammation is typically associated with neurodegenerative diseases. Common causes of chronic neuroinflammation include: Toxic metabolites Autoimmunity Ageing Microbes Viruses Traumatic brain injury Spinal cord injury Air pollution Passive smoke Blast Injury thumb|The initiation of neuroinflammation in the body. Viruses, bacteria, and other infectious agents activate the body's defense systems, prompting immune cells to protect the affected area from damage. Some of these foreign pathogens can trigger a strong inflammatory response that can compromise the integrity of the blood-brain barrier and thus change the flow of inflammation in nearby tissue. The location, along with the type of infection, can determine which inflammatory response is activated and whether specific cytokines or immune cells will act.