Inflammation is a vital homeostatic process that is triggered by cellular injury, regardless of how the harm occurs. Although cellular mediators generated during inflammation can trigger systemic reactions, inflammation is mostly a local phenomenon. The most severe kind of inflammatory reaction, systemic inflammatory response syndrome, can be fatal in severely ill patients. Sepsis is a syndrome that almost often arises in the context of a systemic infection.
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Types of inflammation
Depending upon the defense capacity of the host and duration of response, inflammation can be classified as acute or chronic.
Acute inflammation:
Acute inflammation is of short duration and represents the early body reaction and is usually followed by healing.
Examples of diseases, conditions and situations that can result in acute inflammation include:
- Acute bronchitis
- Sore throat from a cold or flu
- A scratch/cut on the skin
- Acute appendicitis
- Acute dermatitis
- Acute tonsillitis
- Acute infective meningitis
- Acute sinusitis
Chronic inflammation
Chronic inflammation is of a longer duration and occurs either after the causative agents of acute inflammation persists for a long time or the stimulus that induces chronic inflammation from the beginning.
The characteristic features of chronic inflammation are the presence of chronic inflammatory cells such as lymphocytes, plasma cells, and macrophages.
Macrophages (phagocytic cells) are derived from a monocyte, walls of blood vessels, and loose connective tissue. They interact with lymphocytes to facilitate antibody production.
Examples of diseases and conditions with chronic inflammation include:
- Asthma
- Chronic peptic ulcer
- Tuberculosis
- Rheumatoid arthritis
- Chronic periodontitis
- Ulcerative colitis and Crohn’s disease
- Chronic sinusitis
- Chronic active hepatitis.
| Acute Inflammation | Chronic Inflammation | |
|---|---|---|
| Causative agents | Harmful bacteria or injury to tissue. | Non-degradable pathogens that cause persistent inflammation infection with some types of viruses, persistent foreign bodies, overactive immune system reactions. |
| Major cells involved | Mainly neutrophils, basophils (in the inflammatory response), and eosinophil (response to parasites and worms), and mononuclear cells (macrophages, monocytes). | Macrophages, lymphocytes, plasma cells (these three are mononuclear cells), and fibroblasts. |
| Primary mediators | Eicosanoids, vasoactive amines. | Reactive oxygen species, hydrolytic enzymes, IFN-γ, and other cytokines, growth factors. |
| Duration outcomes | Short-lived, only for a few days. The inflammation either gets better (resolution), develops into an abscess, or becomes a chronic inflammation. | From several months to years the destruction of tissue, thickening and scarring of connective tissue (fibrosis), death of cells or tissue (necrosis). |
| Systemic effects | Fever, leukocytosis, lymphangitis (inflammation of lymph node), shock. | Fever, anemia, leukocytosis, increases ESR, Amyoidosis. |
Also Read: Etiology of Inflammation