Understanding the Inflammatory Process

Inflammation, contrary to what the general population considers, is not inherently bad for the body. Inflammation occurs initially after an injury to establish optimum conditions for the tissue to repair itself. Inflammation is characterized by five cardinal signs:

RUBOR (redness)
Reddening of the skin tends to occur in response to histamine release by the mast cells. Histamine is a mediator that leads to increased vascular permeability. This produces an increase in blood flow to the area. Often, blood flow is also increased by massaging of the injured area; people often immediately, subconsciously start rubbing an injured area such as a smashed finger or a bruise.

Histamine can also trigger immune responses. This increases the number of leukocytes in the area to remove damaged tissue and any invading organisms in instances where there is an open wound. Excessive histamine can lead to an autoimmune response where the body also attacks and removes healthy tissue which can further complicate the recovery process.

TUMOR (swelling)
After an acute injury, there is arterial dilation that increases the blood flow to the area. This makes the body part swell which can be useful in containing and isolating the area. This prevents bacteria from entering the area which could cause further damage to the area. In the case of open wounds, swelling can also prevent invading bacteria from spreading to the rest of the body as well. Swelling creates a type of self-splinting as well. This limits the range of motion of the joint so there is not further stress placed on the tissues while they heal. The swelling also puts pressure on the nociceptors of the area creating pain (see dolor).

Chronic swelling can have negative affects on the body. It can lead to chronic pain from the pressure on the nociceptors. If blood flow to the area is impeded, nutrient and waste exchanges cannot occur which will create hypoxia of the tissue and limit repair. Many times orthopedists will “drain joints” such as the knee due to chronic inflammation and swelling but, unless the underlying injury is diagnosed and treated, the swelling will return.

DOLOR (pain)
Pain is your body’s way of saying “don’t do that”. With the injured area being painful, a person is less likely to use it which will decrease the potential for re-injury.

Pain becomes noxious when it becomes chronic. There can be changes in both the peripheral and central nervous systems in response to chronic pain. Some individuals may develop reflex sympathetic disorder where the central nervous system interprets the information as there being greater amounts of pain than should be present based on the injury.

CALOR (increased heat)
The area increases in heat due to the increased blood flow and resultant swelling. Heat can cause protein degradation is beneficial in killing invading microbes and bacteria.

Unfortunately, prolonged heat or fever may lead to denaturing of healthy proteins essential to rebuilding and remodeling the damaged tissue. It may also damage protein-based mediators that are responsible for progressing the area through the stages of healing.

FUNCTIO LAESA (loss of function)
Loss of function is beneficial to protect the area from further injury and to allow it to heal. As the tissue repairs, function improves until it returns to pre-injury status.

In abnormal conditions, function may not return quickly which will require further interventions. The longer the delay in return of function, the more likely a person is to develop compensatory movement patterns which may cause injury and/or pain in other areas.