Inflammation is an acute (short term) response by living tissue to any injury. It is usually followed by repair and regeneration after the injury, provided that the tissue was not severe enough to cause cell death (necrosis). Inflammation is a life sustaining mechanism to help the body cope during and just after an injury but inflammation often prevents proper regeneration and repair. Chronic inflammation may persist long term as seen in many chronic conditions like rheumatoid arthritis and should be treated if there is no direct threat to living tissue.
Causes of Inflammation
Inflammation can be caused by a number of factors that can damage cells but is broadly divided into :
- Physical – can be mechanical as in a car accident injury or assault or environmental like severe cold and heat (burns).
- Chemical – for example : Acid ‘burns’, drugs, venom.
- Infection – bacteria, viruses, fungi and other parasites
- Ischemia – lack of or restricted blood supply which may eventually lead to death of tissue (necrosis) known as an infarct.
- Immune – autoimmune conditions and allergies.
Signs & Symptoms of Inflammation
There are four cardinal signs of inflammation
- Heat or warmth
However a loss of function of the affected area may also be considered as a sign of inflammation. It is important to note that not all the signs and symptoms of inflammation may be clearly evident.
Process of Inflammation
When there is injury to any part of the body, the aterioles (minute blood vessels) in the surrounding tissue dilate (widen). This allows an increased blood flow to the area (redness). Vasoactive substances also increases the permeability (increase pore size) of these arterioles which allows blood cells, chemical mediators, blood proteins and fluid to accumulate in the area. This fluid accumulation causes swelling and may compress nerves in the area resulting in pain. Furthermore, the main chemical mediators of inflammation like prostaglandins, which are produced by cells, may also cause ‘irritation’ of the nerves and further contribute to pain.
Once at the site of injury, the individual components transported by the blood can carry out their necessary functions to protect the tissue. For example : white blood cells may ‘consume’ invading bacteria or the protein fibrin, may commence the clotting process if there is any bleeding. The red blood cells usually do not escape from the micro-vessels in the area unless there is a break in the vessel which may be seen as a hematoma. The chemical process of inflammation along with increased blood supply to the area causes heat.
Treatment of Inflammation
Inflammation is usually a short term process intended to protect the body. Once the cause of the injury has been neutralized or the integrity of the living tissue has been secured, inflammation gradually subsides. Inflammation is a process and not a disease, however it may require treatment if it continues to persist or is causing significant discomfort in the lack of any threat to tissue integrity. In chronic conditions, inflammation is usually persistent but low grade, with occasional acute aggravations.
NSAIDs (Non-Steroidal Antiinflammatory Drugs)
These drugs, like paracetamol, usually act by inhibiting the cells from producing prostaglandins, the main chemical mediator of inflammation.
‘Steroids’ also inhibit prostaglandin formation by the cells as well as inhibiting the function of white blood cells which play an essential role in the inflammatory process.
Histamine is a chemical produced by the white blood cells like basophils and mast cells and is usually secreted in allergic responses. Histamine causes local inflammation and an anti-histamine drug blocks basophils and mast cells from producing and secreting histamine.
Hot & Cold Therapy
Certain applications may also assist with inflammation due to their physical effects on living tissue. Cold applications cause constriction (narrowing) of the blood vessels thereby inhibiting inflammation. Cold also assists with the signs and symptoms of inflammation by causing ‘numbing’ of the area thereby blocking pain and ‘cooling’ the area. Hot applications usually aggravate (worsen) inflammation but may help with easing the cause of inflammation like spasms or cramping of muscles. Hot and cold therapy should be used cautiously under the supervision of a medical practitioner to prevent tissue death (necrosis).
Article reviewed by Dr. Greg. Last updated on December 16, 2011