What to do if you have a central nervous system infection

The human central nervous system is one of the most important systems that affects the human body, and central nervous system infection is also a very common problem. If a person's central nervous system is infected, it will cause problems such as meningitis, meningitis, and encephalitis. So what kind of disease is central nervous system infection? What are the pathological causes of central nervous system infection?

If you have a central nervous system infection, how will your health be affected? What are the factors that cause central nervous system infections? How should we correctly view central nervous system infections?

Central nervous system infections include meningitis (inflammation of the meninges or spinal cord), encephalitis (clinical manifestation of the brain caused by bacterial invasion of the central nervous system), encephalitis (clinical manifestation of the brain caused by viral infection of the central nervous system), abscesses and worm infections. The central nervous system has a strong resistance to invasion by various pathogens, but once the brain and spinal cord are infected, the consequences are very serious.

Mode of transmission

Because of the existence of the brain barrier, it is difficult for pathogens to enter the central nervous system of normal people. The brain barrier includes the blood-brain barrier, the blood-cerebrospinal fluid barrier, and the cerebrospinal fluid-brain barrier. It also includes the scalp, skull, dura mater, arachnoid mater, pia mater, etc. However, in neurosurgery, the brain barrier is damaged due to various reasons, such as cerebrospinal fluid leakage caused by surgery and trauma, congenital malformations leading to incomplete development of the brain barrier, and the brain barrier function of infants and young children is not yet fully developed. Pathogens can spread into the central nervous system through wounds, drainage tubes, cerebrospinal fluid leaks, and the blood system. Cerebrospinal fluid leakage includes cerebrospinal fluid otorrhea and nasal leakage, and pathogens can invade the skull from the external auditory canal, nasal cavity, etc. Because of the destruction of the brain barrier, infections in other parts of the body, such as the lungs and intestines, can directly enter the central nervous system through the damaged brain barrier and multiply. [1]

pathology

Central nervous system infection can cause mild, recurrent, or even fatal illness, or no illness due to differences in individual immune responses. Proteins in the blood cannot diffuse easily into the CNS, thus hindering the production of antibodies. In normal cerebrospinal fluid (CSF), IgG and IgA are found but IgM is absent because IgM has a larger molecular weight. Humoral immune response often forms antigen-antibody complexes; this reaction often occurs within blood vessels, leading to severe vascular inflammatory reactions within neural tissue or adjacent tissues.

1. Inflammatory reactions caused by CNS infections: Due to the virulence of the pathogen and the body's response, it can manifest as (1) suppurative inflammatory reactions, often caused by suppurative bacteria; (2) non-suppurative inflammatory reactions, such as typhus; (3) hemorrhagic reactions, seen in anthrax and certain viral infections; (4) histiocyte and granulomatous reactions, seen in chronic inflammatory processes.

2. Myelin destruction is common in CNS infections: Myelin destruction can be secondary to neuronal damage, known as neuronolytic demyelination, and another type is called periaxial demyelination. The latter can be seen in viral infections as well as in demyelinating diseases. There are five possible mechanisms that may cause demyelination during the inflammatory process: ① direct viral cytopathic effects on oligodendrocytes; ② immune-mediated changes in viral tropism for oligodendrocytes; ③ immune-mediated destruction of infected oligodendrocytes; ④ virus-induced autoimmune demyelination; and ⑤ "bystander" demyelination. Demyelination may be accompanied by remyelination, leading to symptom relief. It was once believed that only peripheral nerves remyelinated. This is very important for recovery.

3. Meningitis is the most common CNS infection: Bacteria cause meningitis and are associated with three components: (1) bacterial capsule (2) bacterial cell wall (3) lipopolysaccharide. Some bacteria, such as influenza bacillus and meningococci, have a polysaccharide-containing envelope outside the cell, which makes it easy for the bacteria to invade the host. The distinction between gram-positive and gram-negative bacteria is primarily based on their cell wall. The cell wall of positive bacteria contains a large amount of peptidoglycan, while that of negative bacteria contains only a small amount; the cell wall of positive bacteria also contains teichoic acid, while that of negative bacteria does not. Both substances induce a strong meningeal inflammatory response. However, negative bacteria have lipopolysaccharide molecules attached to the outer membrane, which contain the toxic lipid substance "lipid A". When the bacteria die, it is released and acts like endotoxin, also causing a strong meningeal inflammatory reaction. Certain cytokines play an important role in mediating inflammatory responses during meningitis.

Such as tumor necrosis factor (TNFα; cachectin) and interleukin-1. Both substances stimulate endothelial cell adhesion and promote neutrophil entry into the CNS, triggering the inflammatory process. Platelet-activating factor, arachidonic acid metabolites and other interleukins are also involved in this inflammatory process. Due to the deficiency of humoral factors and phagocytes in CSF, pathogens rapidly divide and multiply, releasing components of bacterial cell walls or membranes, leading to the rapid development of meningitis and damage to vascular endothelial cells. The permeability of the blood-brain barrier (BBB) ​​also increases, resulting in angioedema. A large number of multinuclear leukocytes enter the subarachnoid space and release toxic substances. Although these toxic substances are used to defend against pathogens, they also cause cytotoxic edema due to the lack of ability to distinguish between "foreign" and "self". These conditions will further affect CSF dynamics, brain metabolism and cerebral vascular self-regulation. If inflammation cannot be controlled, severe cerebral edema, increased intracranial pressure and reduced cerebral blood circulation will occur, leading to neuronal damage and irreversible focal or diffuse brain damage.

The principle of treatment is mainly to eliminate or inhibit pathogens, which often requires external intervention, such as antibacterial drugs and removal of lesions. It is also important to stimulate or promote moderate improvements in the body's humoral and cellular immune mechanisms to enhance defense and repair capabilities. In addition, correcting or regulating pathophysiological mechanisms to reduce the damage of inflammatory reactions to target organs, protecting brain function, and paying attention to water and electrolyte balance are also extremely important auxiliary means of treatment.

The above are some common questions about central nervous system infections. Finally, I would like to remind you that if a family member has a central nervous system infection, you must give them the best care, never despise them, and don’t put too much psychological pressure on them. This will be more conducive to their recovery.