Cardinal Signs of Inflammation
- Pain
- Heat
- Redness
- Swelling
- Loss of function

Duration and Complications of Inflammation
- Acute inflammation lasts a few days
- Chronic inflammation can last months or years
- Complications of inflammation include asthma, pneumonia, and autoimmune diseases

Causes of Inflammation
- Infection
- Physical injury
- Autoimmune disorders

Classification of Inflammation
- Acute inflammation is the initial response to harmful stimuli
- Chronic inflammation involves a shift in cell types and simultaneous tissue destruction and healing
- Inflammation can also be classified as Type 1 or Type 2 based on cytokines and helper T cells involved

Inflammation and Infection
- Inflammation is the body's immunovascular response to harmful stimuli
- Infection refers to microbial invasion and the body's inflammatory response
- Inflammation can also be caused by non-infectious factors such as atherosclerosis and autoimmune diseases

Acute Inflammation
- Acute inflammation is the first line of defense against injury.
- Inflammatory mediators are short-lived and quickly degraded in the tissue.
- Acute inflammation ceases once the stimulus is removed.
- The inflammatory response involves the migration of leukocytes, mainly neutrophils and macrophages, to the site of injury.
- Acellular biochemical cascade systems, such as the complement system and coagulation system, also contribute to the inflammatory response.

Chronic Inflammation
- Chronic inflammation lasts for months or years.
- Macrophages, lymphocytes, and plasma cells predominate in chronic inflammation.
- Chronic inflammation is associated with diseases like diabetes, cardiovascular disease, allergies, and COPD.
- Factors like obesity, smoking, stress, and insufficient diet can promote chronic inflammation.
- A 2014 study reported that 60% of Americans had at least one chronic inflammatory condition.

Cardinal Signs of Chronic Inflammation
- Common signs and symptoms of chronic inflammation include body pain, arthralgia, and myalgia.
- Chronic inflammation can cause chronic fatigue, insomnia, depression, anxiety, and mood disorders.
- Gastrointestinal complications like constipation, diarrhea, and acid reflux can occur.
- Weight gain or loss may be observed in chronic inflammation.
- Frequent infections can be a result of chronic inflammation.

Vascular Component of Acute Inflammation
- Acute inflammation involves vasodilation and increased permeability of blood vessels.
- Vasoactive amines like histamine and serotonin, as well as eicosanoids like prostaglandin E2 and leukotriene B4, contribute to vasodilation.
- Nitric oxide released by macrophages and endothelial cells also contributes to vasodilation.
- Increased permeability allows plasma fluid, containing important proteins, to move into the inflamed tissue.
- The collection of fluid in the tissue causes swelling (edema) and facilitates antimicrobial actions.

Plasma Cascade Systems
- The complement system promotes opsonization, chemotaxis, and agglutination.
- The kinin system generates proteins that sustain vasodilation and other physical inflammatory effects.
- The coagulation system forms a protective protein mesh over injury sites.
- The fibrinolysis system counterbalances clotting and generates inflammatory mediators.
- These plasma cascade systems play a crucial role in the inflammatory response.

Cellular Component
- Leukocytes reside in the blood and move into inflamed tissue via extravasation.
- Some leukocytes act as phagocytes, ingesting bacteria, viruses, and cellular debris.
- Leukocytes release enzymatic granules that damage pathogenic invaders.
- Leukocytes release inflammatory mediators that develop and maintain the inflammatory response.
- Acute inflammation is mediated by granulocytes, while chronic inflammation is mediated by mononuclear cells.

Leukocyte Extravasation
- Neutrophils migrate from blood vessels to infected tissue via chemotaxis.
- Neutrophils remove pathogens through phagocytosis and degranulation.
- Inflammation is a protective immune response against foreign organisms.
- In autoimmune diseases, the immune system triggers an inflammatory response against normal tissues.
- Leukocyte extravasation involves leukocyte margination, endothelial adhesion, transmigration, and movement within the tissue via chemotaxis.

- Extravasated neutrophils come into contact with microbes at the inflamed tissue.
- Phagocytes express endocytic pattern recognition receptors (PRRs) that bind to non-specific microbe-associated molecular patterns (PAMPs).
- Actin-myosin cytoskeletal rearrangement occurs to endocytose the plasma membrane containing the PRR-PAMP complex and the microbe.
- Phagosome is trafficked to intracellular lysosomes, forming a phagolysosome that kills microbes.
- Opsonization enhances phagocytic efficacy by binding complement C3b and antibodies to microbial antigens.

Cell-Derived Mediators
- Lysosome granules in granulocytes contain enzymes that act as inflammatory mediators.
- GM-CSF, produced by macrophages, monocytes, T-cells, B-cells, and tissue-resident cells, contributes to inflammation in various conditions.
- Histamine, stored in mast cells and basophils, causes arteriole dilation, increased permeability, and organ-specific effects.
- IFN-γ, produced by T-cells and NK cells, has antiviral, immunoregulatory, and anti-tumor properties.
- Cell-derived mediators play important roles in inflammation and its associated effects.

Other Factors
- Inflammatory cytokines IL-1 and TNFα induce the expression of adhesion molecules on endothelial cells.

Merriam-Webster Online Dictionary
inflammation (noun)
a local response to cellular injury that is marked by capillary dilatation, leukocytic infiltration, redness, heat, and pain and that serves as a mechanism initiating the elimination of noxious agents and of damaged tissue
the act of the state of being - inflaming inflamed
Inflammation (Wikipedia)

Inflammation (from Latin: inflammatio) is part of the biological response of body tissues to harmful stimuli, such as pathogens, damaged cells, or irritants. It is a protective response involving immune cells, blood vessels, and molecular mediators. The function of inflammation is to eliminate the initial cause of cell injury, clear out damaged cells and tissues, and initiate tissue repair.

The cardinal signs of inflammation include: pain, heat, redness, swelling, and loss of function. Some of these indicators can be seen here due to an allergic reaction.
SpecialtyImmunology, rheumatology
SymptomsHeat, pain, redness, swelling
ComplicationsAsthma, pneumonia, autoimmune diseases
DurationAcute: few days
Chronic: up to many months, or years
CausesInfection, physical injury, autoimmune disorder

The five cardinal signs are heat, pain, redness, swelling, and loss of function (Latin calor, dolor, rubor, tumor, and functio laesa). Inflammation is a generic response, and therefore it is considered as a mechanism of innate immunity, as compared to adaptive immunity, which is specific for each pathogen. Too little inflammation could lead to progressive tissue destruction by the harmful stimulus (e.g. bacteria) and compromise the survival of the organism. In contrast, too much inflammation, in the form of chronic inflammation, is associated with various diseases, such as hay fever, periodontal disease, atherosclerosis, and osteoarthritis.

Inflammation can be classified as either acute or chronic. Acute inflammation is the initial response of the body to harmful stimuli, and is achieved by the increased movement of plasma and leukocytes (in particular granulocytes) from the blood into the injured tissues. A series of biochemical events propagates and matures the inflammatory response, involving the local vascular system, the immune system, and various cells within the injured tissue. Prolonged inflammation, known as chronic inflammation, leads to a progressive shift in the type of cells present at the site of inflammation, such as mononuclear cells, and is characterized by simultaneous destruction and healing of the tissue from the inflammatory process.

Inflammation has also been classified as Type 1 and Type 2 based on the type of cytokines and helper T cells (Th1 and Th2) involved.

Inflammation is not a synonym for infection. Infection describes the interaction between the action of microbial invasion and the reaction of the body's inflammatory response—the two components are considered together when discussing an infection, and the word is used to imply a microbial invasive cause for the observed inflammatory reaction. Inflammation, on the other hand, describes purely the body's immunovascular response—whatever the cause may be. But because of how often the two are correlated, words ending in the suffix -itis (which refers to inflammation) are sometimes informally described as referring to infection. For example, the word urethritis strictly means only "urethral inflammation", but clinical health care providers usually discuss urethritis as a urethral infection because urethral microbial invasion is the most common cause of urethritis.

However, the inflammation–infection distinction becomes crucial for situations in pathology and medical diagnosis where inflammation is not driven by microbial invasion, such as the cases of atherosclerosis, trauma, ischemia, and autoimmune diseases (including type III hypersensitivity).

Inflammation (Wiktionary)



From Middle French inflammation, from Latin īnflammātiō.



inflammation (countable and uncountable, plural inflammations)

  1. The act of inflaming, kindling, or setting on fire.
  2. The state of being inflamed
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