What Is the Relationship between Infection and Inflammation?

Inflammation: It is what people usually call "inflammation", which is a kind of defense response of the body to stimuli, manifested as redness, swelling, heat, pain and dysfunction. Inflammation can be infectious inflammation caused by infection or non-infectious inflammation caused by infection. In general, inflammation is beneficial and is an automatic defense response of the human body, but sometimes it is also harmful, such as attacks on the human body's own tissues, inflammation that occurs in transparent tissues, and so on.

Chinese name: Inflammation

Foreign name: inflammation

Inflammation classification

1. It is divided into acute and chronic according to the duration.

The main symptoms of acute inflammation are redness, swelling, pain, etc., that is, inflammation mainly composed of the response of the vascular system. Local vasodilation, slow blood, blood components such as plasma and neutrophils seep into the tissues, and the exudation is mainly centered in the vein, but the exudation of high-molecular substances such as proteins only uses the pressure difference inside and outside the blood vessel and colloids The pressure difference cannot be explained, and the role of substances that can enhance vascular permeability is valued.

This substance mainly includes: (1) amines such as histamine and serotonin can cause immediate reactions after inflammation. (2) Polypeptides represented by bradykinin, lysyl kallidin, and methio-nyl-lysyl-bradykinin. Its common features are that it can increase vascular permeability, smooth muscle contraction, vasodilation, and promote leukocyte migration. The structures of bradykinin and lysyl bradykinin have been determined. (3) Proteases such as plasmin, kallikrein, globulin-PF, etc., cannot themselves be the substance of vascular permeability. However, it can make kininoge into kinin and play a role. However, the location and mechanism of these substances on blood vessels are mostly unknown. Histologically, we can see that the vascular exudation response and the repair process are mixed when acute inflammation occurs. And the infiltration of macrophages, lymphocytes, plasma cells and fibroblast proliferation.

2. The main tissue changes from inflammation can be classified as follows: (1) Metamorphic inflammation. (2) Exudative inflammation (serous inflammation, fibrinous inflammation, suppurative inflammation, hemorrhagic inflammation, necrotic inflammation, catarrhitis). (3) Proliferative inflammation. (4) Specific inflammation (tuberculosis, syphilis, leprosy, lymphogranuloma, etc.)

Causes of inflammation

Any factor that can cause tissue damage can be the cause of inflammation, namely the inflammatory agent. Can be grouped into the following categories:

Inflammatory biological factors

Bacteria, viruses, Rickettsia, Mycoplasma, fungi, Borrelia, and parasites are the most common causes of inflammation. Inflammation caused by biological pathogens is also called infection. Exotoxins and endotoxins produced by bacteria can directly damage tissues; viruses replicate in infected cells and cause cell necrosis; certain antigenic pathogens injure tissues through induced immune responses, such as parasitic infection and tuberculosis.

Physical factors of inflammation

High temperature, low temperature, radioactive materials, ultraviolet rays, etc. and mechanical damage.

Inflammatory chemical factors

Exogenous chemicals such as strong acids, alkalis, turpentine, mustard gas, etc. Endogenous toxic substances such as decomposition products of necrotic tissue and metabolites such as urea accumulated in the body under certain pathological conditions.

Inflammatory foreign body

Foreign bodies that enter the human body through various means, such as various metals, wood chips, dust particles, and surgical sutures, etc., can cause different levels of inflammatory reactions due to their different antigenicity.

Inflammatory necrosis tissue

Ischemia or hypoxia can cause tissue necrosis, which is a potential inflammatory factor. Congestive bleeding bands and infiltration of inflammatory cells at the edge of fresh infarcts are manifestations of inflammation.

Inflammatory allergy

When the body's immune response is abnormal, it can cause an inappropriate or excessive immune response, causing tissue and cell damage and causing inflammation. Tissue damage caused by immune reactions is most common in various types of hypersensitivity reactions: type I allergies such as allergic rhinitis, urticaria, type II allergies such as anti-basal membrane glomerulonephritis, and type III allergies such as immunity Glomerulonephritis caused by complexes, type IV allergic reactions such as tuberculosis, typhoid fever, etc. In addition, there are many autoimmune diseases such as lymphocytic thyroiditis, ulcerative colitis and so on.

Pathological changes of inflammation

Basic pathological changes of inflammation The basic pathological changes of inflammation are generally summarized as the deterioration, exudation and proliferation of local tissues.

Local manifestations of inflammation

The most prominent is body surface inflammation, which usually manifests as redness, swelling, heat, pain, and dysfunction. The mechanism is:

1. Red: It is caused by hyperemia in the inflammatory lesion. Due to arterial hyperemia in the initial stage of inflammation, local oxygenated hemoglobin increases, so it is bright red. With the development of inflammation, the blood flow is slow, congestion and stagnation, and the local tissue contains reduced hemoglobin, so it is dark red.

2. Swelling: mainly due to exudate, especially inflammatory edema. In chronic inflammation, tissue and cell proliferation can also cause local swelling.

3 Fever: Fever is caused by arterial congestion and enhanced metabolism. Interleukin (IL-1), tumor necrosis factor (TNF), and prostaglandin E (PGE) produced by leukocytes can cause fever.

4 Pain: The factors that cause local pain in inflammation are related to many factors. The accumulation of potassium and hydrogen ions in local inflammatory lesions, especially the stimulation of inflammatory mediators such as prostaglandins, serotonin, bradykinin, etc. are the main causes of pain. Exudates from inflammatory lesions cause tissue swelling, increased tension, and compression of nerve endings can cause pain. Therefore, the pain of loose tissue is relatively mild, and inflammation of the pulp and periosteum often causes severe pain. In addition, the inflamed organs are enlarged. The tension of the membrane rich in sensory nerve endings is increased, and the nerve endings are stretched to cause pain.

5. Dysfunction: Degeneration, necrosis, abnormal metabolic function, and mechanical obstruction caused by inflammatory exudate in inflammatory foci may cause dysfunction of inflammatory organs. Pain can also affect the mobility of the limbs.

Inflammation inflammation in the whole body

The inflammatory lesions are mainly local, but local lesions and the whole affect each other. In more serious inflammatory diseases, especially when pathogenic microorganisms spread and spread in the body, obvious systemic reactions often occur.

Inflammatory fever

Fever

Infection with pathogenic microorganisms often causes fever. Both pathogenic microorganisms and their products can be used as fever activators, acting on EP-producing cells to produce EP, which in turn acts on the body's temperature regulation center, causing its set point to move up, thereby causing fever.

A certain increase in body temperature can enhance the body's metabolism, promote the formation of antibodies, enhance the phagocytic function of phagocytes and the barrier detoxification function of the liver, thereby improving the body's defense function. However, the fever exceeds a certain degree or long-term fever, which can affect the metabolic process of the body and cause dysfunction of multiple systems, especially the central nervous system. If the inflammatory lesions are very serious, but the body temperature does not rise, it means that the body is poorly responsive and the resistance is low, which is a sign of poor prognosis.

Inflammatory leukocytosis

In acute inflammation, especially acute inflammation caused by bacterial infection, peripheral white blood cell count can be significantly increased. In severe infections, there is often an increase in the proportion of naive neutrophils in the peripheral blood, which is clinically referred to as "nuclear left shift". This reflects the patient's greater resistance to infection and the severity of the infection. In the course of certain inflammatory diseases, such as typhoid fever, viral diseases (influenza, viral hepatitis, and infectious atypical pneumonia), rickettsia infection, and some autoimmune diseases (such as SLE), the white blood cells in the blood It often does not increase, sometimes it decreases instead. Bronchial asthma and parasite infections increase blood eosinophil counts.

Cell proliferation of inflammatory monocyte phagocytic system

Cell proliferation in the monocyte phagocytic system is a manifestation of the body's defense response. During inflammation, especially by pathogenic microorganisms, the cells of the monocyte phagocytic system often proliferate to varying degrees. Often manifested as local lymph nodes, liver, and splenomegaly. Macrophages in the bone marrow, liver, spleen, and lymph nodes proliferate, and their ability to digest and digest is enhanced. B and T lymphocytes in lymphoid tissues also proliferated, and the function of releasing lymphokines and secreting antibodies was enhanced.

Pathological changes of parenchymal organs

When inflammation is severe, due to the effects of pathogenic microorganisms and their toxins, as well as local blood circulation disorders, fever and other factors, the parenchymal cells of the heart, liver, kidney and other organs may undergo varying degrees of degeneration, necrosis and organ dysfunction.

Defensive effect:

During the inflammatory process, a series of local reactions centered on the vascular system confines and eliminates damage factors, while also promoting the healing of damaged tissues. The exudation of liquid can dilute toxins, swallow and transport necrotic tissue to facilitate regeneration and repair, and limit pathogenic factors to the site of inflammation without spreading the whole body. Therefore, inflammation is a natural local response based on defense. Generally speaking, it is beneficial to the body. It is conceivable that if there is no inflammatory response, bacterial infections cannot be controlled, and the damage can never heal, which can cause serious harm to the body.

But in some cases, inflammation can be potentially harmful. Inflammatory response is the basis of some diseases, such as severe hypersensitivity, which can threaten the patient's life when the inflammation is too severe. In addition, inflammation in special parts or organs can cause serious consequences. For example, inflammation of the brain or brain can compress the center of life. Inflammation of the vocal cords can block the throat and cause asphyxia. Severe myocarditis can affect heart function. At this time, anti-inflammatory drugs should be used. Suppresses inflammation.