The steps
The healing response
Inflammation is the immune system's response to an irritant, such as a germ. Its classic signs are redness, heat, swelling, pain and loss of function.
Inflammation (the healing response)
Source: InformedHealth.org (IQWiG), NCBI Bookshelf, In brief: What is an inflammation?
The pain signals
Injured cells make chemicals called prostaglandins. NSAIDs such as ibuprofen reduce pain and inflammation by stopping cells from making them.
A natural brake
Cortisol, a hormone made by the adrenal glands, reduces inflammation. Corticosteroid medicines are man-made versions of cortisol.
Sources: Pathology Tests Explained, Cortisol; Better Health Channel (Victorian Government), Hormones: cortisol and corticosteroids
When it lasts
In chronic inflammation the immune system keeps sending out chemical messengers. Autoimmune diseases such as rheumatoid arthritis are among the conditions with long-lasting inflammation.
Chronic low-grade inflammation
Sources: InformedHealth.org (IQWiG), NCBI Bookshelf, In brief: What is an inflammation?; Pathology Tests Explained, C-reactive protein
Measuring it
The liver releases C-reactive protein in response to inflammation. Most infections and inflammations push CRP above 10 mg/L.
Inflammation in the airways
In asthma, the airway lining swells and becomes inflamed. Preventer inhalers contain a corticosteroid that makes the airways less sensitive and reduces redness and swelling.
Sources: Better Health Channel (Victorian Government), Asthma; Asthma Australia, Preventers
Quiz
1. What are the classic signs of inflammation?
Answer: Redness, heat, swelling, pain and loss of function. The five signs of acute inflammation are redness, heat, swelling, pain and loss of function, though not every inflammation causes all five.
Source: InformedHealth.org (IQWiG), NCBI Bookshelf, In brief: What is an inflammation?
2. How do NSAIDs such as ibuprofen reduce pain and inflammation?
Answer: By stopping cells making prostaglandins. NSAIDs reduce pain and inflammation by stopping injured cells from making chemicals called prostaglandins.
3. Which blood test rises with inflammation?
Answer: CRP. C-reactive protein is released by the liver in response to inflammation.