Understanding The 3 Phases Of Inflammation

Understanding The 3 Phases Of Inflammation

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The body’s response to injury is called inflammation. Physical traumas such as sprain, strain or bruise are most common, whereas injuries can also occur from bacterial or viral infections, heat or any sort of chemical injury. Trauma causes direct damage to cells in the immediate area of injury, causing bleeding. A stream of events is initiated due to bleeding that results in the inflammatory process, which promotes healing of the injured tissue.

Acute and chronic are terms commonly used to refer to the duration or the length of the problem, giving inaccurate information about the actual stage of inflammation. Progression from acute to chronic inflammation can result from persistent injury or individual factors such as, diabetes, corticosteroid use, blood disorders, etc.

  • Inflammatory Response: Acute swelling stage (Phase 1)

This is a fundamental type of response by the body to disease and injury. It is characterized by the classical signs of dolor, calor, rubor and tumor – pain, heat, redness and swelling. Inflammation is a key part of the body’s defense system, an indispensable protective response by the body’s system of self-defense. Innumerable causes (mosquito bite, a splinter, a virus infection, a bruise, a broken bone) can trigger an inflammatory response and dispatch cells and chemicals to the site to repair the damage.

Acute swelling is short lived, lasting for only a few days. If it lasts longer, it is referred to as chronic inflammation. Chronic inflammation may last for weeks, months or beyond.

  • Subacute: Repair and Regeneration (Phase 2)

In this phase, special cells go into the area of the damaged tissue and start building new tissues. The subacute stage is the time of healing and repair. New collagen fibers are laid down in a disorganized manner in the form of a scar and there are weak links between each fiber. This new tissue is fragile and must be handled gently as it can be easily injured.

  • Chronic: Remodelling and Maturation (Phase 3)

As the healing process continues, the tissue starts to remodel, strengthen and improve its cellular organization. Signs of inflammation are absent and scar tissue starts maturing. Maturation refers to the growth of fibroblasts to fibrocytes and remodelling refers to the organization of and shrinking of collagen fibres along lines of stress. There is less new collagen formation, but increased organization of collagen fibers, and stronger bonds between them. 

In order to determine if the condition of the injury is in the acute, subacute or chronic inflammatory stage, an adequate case history is needed along with assessment. The assessment should include a visual scan, active muscle testing, passive range of motion testing and resisted isometric muscle tests and palpation of the structure involved. A physiotherapist can thoroughly examine a prolonged chronic stage if it is not healing properly.