What is inflammation? The body's inflammatory response

Our bodies often have a lot of inflammation. The main reactions of inflammation are swelling, redness, pain and fever. There are also systemic reactions such as leukocytosis. If the baby's fever is caused by inflammation, the white blood cell count will increase in the blood.

1. Local manifestations

1. Red: It is caused by congestion in the inflammatory lesions. In the early stage of inflammation, due to arterial congestion, the local oxygenated hemoglobin increases, so it appears bright red. As inflammation progresses, blood flow slows down, congestion and stagnation occur, and local tissues contain more reduced hemoglobin, so they appear dark red.

2. Swelling: Mainly caused by 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 Ⅰ (IL-1), tumor necrosis factor (TNF) and prostaglandin E (PGE) produced by white blood cells can cause fever.

4. Pain: The factors that cause local pain caused by inflammation are related to many factors. The accumulation of potassium ions and hydrogen ions in local inflammatory lesions, especially the stimulation of inflammatory mediators such as prostaglandins, 5-hydroxytryptamine, bradykinin, etc., is the main cause of pain. The exudate in the inflammatory lesion causes tissue swelling, increased tension, and compression of nerve endings, which can cause pain. Therefore, the pain is relatively mild when loose tissue is inflamed, while inflammation of the pulp and periosteum often causes severe pain. In addition, the inflamed organs swell, which increases the tension of the membrane rich in sensory nerve endings, and the nerve endings are pulled, causing pain.

5. Functional disorders: Degeneration, necrosis, metabolic dysfunction of parenchymal cells within the inflammatory focus, mechanical obstruction and compression caused by inflammatory exudates, etc. may cause functional disorders of the inflamed organs. Pain can also affect the movement function of the limbs.

2. Systemic reactions

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

(1) Fever

Infection with pathogenic microorganisms often causes fever. Pathogenic microorganisms and their products can act as fever activators, acting on EP-producing cells to produce EP, which then acts on the body temperature regulation center to shift its set point upward, thereby causing fever.

A certain degree of increase in body temperature can enhance the body's metabolism, promote the formation of antibodies, enhance the phagocytic function of macrophages and the barrier detoxification function of the liver, thereby improving the body's defense function. However, if the fever exceeds a certain level or lasts for a long time, it can affect the body's metabolic process and cause functional disorders in 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 has low resistance, which is a sign of a poor prognosis.

(2) Leukocytosis

In acute inflammation, especially acute inflammation caused by bacterial infection, the peripheral blood leukocyte count may increase significantly. In severe infections, there is often an increase in the proportion of immature neutrophils in the peripheral blood, which is clinically known as "nuclear left shift." This reflects the patient's greater resistance to infection and the severity of the infection. During certain inflammatory diseases, such as typhoid fever, viral diseases (influenza, viral hepatitis and infectious atypical pneumonia), rickettsial infections and certain autoimmune diseases (such as SLE), the number of white blood cells in the blood often does not increase, and sometimes decreases. In bronchial asthma and parasitic infections, the eosinophil count in the blood increases.