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INTRO TO CHRONIC INFLAMMATION

INTRO TO CHRONIC INFLAMMATION

What is chronic inflammation? 

Pic: http://www.novimmune.com/img/arthritis.jpg
Pic: http://www.novimmune.com/img/arthritis.jpg

Chronic inflammation, like I discussed in Intro to Acute Inflammation, is the result of the healing process going wrong. This can happen when certain things trigger the inflammatory process to begin with: instead of the healing process taking days or up to a few weeks (in the case of broken bones), it can proceed for months or even years. This unfortunately, can happen more and more often as we become older and our immune systems aren’t as strong and efficient as they once were when we were young adults: a classic example of chronic inflammation is arthritis.

What lab tests can be performed to detect chronic inflammation? 

As I mentioned in Inflammation Mechanisms, there are several acute phase proteins which are examined with a biochemistry analyzer. There are four different types of proteins which have differing levels from normal when chronic inflammation is present:

Pic: http://www.flinders.edu.au/medicine/fms/sites/biomedical_engineering/images/eqpt-intro/Biochem_400.jpg
Pic: http://www.flinders.edu.au/medicine/fms/sites/biomedical_engineering/images/eqpt-intro/Biochem_400.jpg
  • The albumin may be decreased (or may be normal)
  • The alpha-1 and alpha-2 globulins are mildly raised
  • The gamma globulins are significantly raised
  • The C-reactive protein is at its peak level

What causes chronic inflammation? 

There are several things that can lead to chronic inflammation. The Smart Art Graphic below demonstrates the different triggers.

Smart Art Graphic: Original
Smart Art Graphic: Original

What are the characteristics of chronic inflammation? 

Table: Original
Table: Original

There are three different characteristics that signal the presence of chronic inflammation: they include repair, tissue destruction and infiltration with mononuclear cells. These characteristics are discussed in the table alongside. Information regarding mononuclear cells can be seen in Intro to the Immune System. 

How do macrophages and lymphocytes interact in the chronic inflammatory response? 

Pic: http://classconnection.s3.amazonaws.com/723/flashcards/656723/png/screen_shot_2012-09-11_at_10556_pm1347386766870.png
Pic: http://classconnection.s3.amazonaws.com/723/flashcards/656723/png/screen_shot_2012-09-11_at_10556_pm1347386766870.png

As the picture alongside demonstrates, macrophages and lymphocytes interact with each other in a way that helps stimulate the opposite cell. These activated cells then release inflammatory mediators such as IFN-y (interferon gamma), IL-1 (interleukin 1) and TNF (tumour-necrosis factor). IFN-y helps to activate macrophages as well as help in the innate immune processes. IL-1 has a pro-inflammatory effect. TNF helps regulate immune cells.

What is granulomatus inflammation? 

Granulomatus inflammation is a specific type of chronic inflammation. This can happen when macrophages are unable to digest the foreign material: instead, several of these cells surround the infectious agent or foreign body and form granulomas. There are only a few conditions which can lead to granulomatus inflammation, and the causes and effects are listed in the table below. In case you’re asking what the term ‘caseating’ means, it basically means that during the process of the granuloma forming, the tissue in the middle of the granuloma necrotizes (dies) and turns into a structure similar to that of cheese. TB is the only one that tends to do this, hence it is easy to diagnose.

Table: Original
Table: Original

What disorders of chronic inflammation are there? 

There are five different types of white-cell induced injuries, they are listed in the table below.

Table: Original
Table: Original