Inflammation is a response to a noxious stimuli which can be either be acute or chronic.

The cardinal signs of inflammation include:

  • heat
  • redness
  • swelling
  • pain
  • loss of tissue function

Sub types

Acute Inflammation

Acute inflammation occurs within the first few hours after an injury.

In acute inflammation there are vascular and exudative phases.

  • vascular: dilatation and increased permeability
  • exudative: fluid and cells escape from permeable venules

The outcome of acute inflammation can be:

  • resolution (restoration of normal function)
  • non resolution
  • abcess
  • organization (scarring)
  • progression to chronic inflammation
Chronic Inflammation

Chronic inflammation occurs when there is a persistent damaging stimulus. This eventually heals by either scarring or granuloma formation.

Chronic inflammation differs from acute inflammation as it can last for a much longer period of time i.e. from months to years.

Chronic inflammation is characterized by infiltration with mononuclear cells (macrophages, lymphocytes).

Outcomes of chronic inflammation include:

  • a continuing response to persisting inflammatory triggers, such as infectious agents, autoimmune products, and immune complexes.
  • the inflammatory cells including lymphocytes and macrophages will either be cleared or remain at the site.
  • the development of giant cells along with fibrosis and/or necrosis.
Granulomatous Inflammation

Granulomatous inflammation is specific subtype of chronic inflammation charcterised by aggregation of epitheliod histiocytes. Examples of Type IV hypersensitivity reaction include:

  • infections (tuberculosis)
  • foreign bodies
  • chemicals
  • drugs
  • idiopathic (eg. sarcoid)
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Article information

rID: 16594
Section: Pathology
Synonyms or Alternate Spellings:

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