These cells begin an inflammatory response to trap bacteria and other offending agents or start healing injured tissue. The result can be pain, swelling, bruising or redness.
Resolution of inflammation is driven by a complex set of mediators that regulate cellular events required to clear inflammatory cells from sites of infection or injury to restore tissue function. However, recent studies suggest that resolution is not the end of innate mediated immune responses to infection/injury.
The four cardinal signs of inflammation—redness (Latin rubor), heat (calor), swelling (tumor), and pain (dolor)—were described in the 1st century ad by the Roman medical writer Aulus Cornelius Celsus. Redness is caused by the dilation of small blood vessels in the area of injury.
The inflammatory response (inflammation) occurs when tissues are injured by bacteria, trauma, toxins, heat, or any other cause. The damaged cells release chemicals including histamine, bradykinin, and prostaglandins. These chemicals cause blood vessels to leak fluid into the tissues, causing swelling.
The function of inflammation is to eliminate the initial cause of cell injury, clear out necrotic cells and tissues damaged from the original insult and the inflammatory process, and initiate tissue repair.
The series of events in the process of inflammation are: Vasodilation: leads to greater blood flow to the area of inflammation, resulting in redness and heat. Vascular permeability: endothelial cells become "leaky" from either direct endothelial cell injury or via chemical mediators.
The goals of the inflammatory response are to: Prevent initial establishment of infection or remove damaged tissue. Prevent the spread of infection or repair damaged tissue. Recruit effector cells if the immune cells of the innate immune system cannot control infection or repair damaged tissue.
The wound healing process is usually characterized as four sequential but overlapping phases: haemostasis (0–several hours after injury), inflammation (1–3 days), proliferation (4–21 days) and remodelling (21 days–1 year) [1].
Inflammation is the immune system's response to harmful stimuli, such as pathogens, damaged cells, toxic compounds, or irradiation [1], and acts by removing injurious stimuli and initiating the healing process [2]. Inflammation is therefore a defense mechanism that is vital to health [3].
Phase 1: Inflammatory Response
The damaged cells are removed and the body begins to put new collagen in the area of injury. This phase is initiated immediately after injury and lasts 3-5 days.
Chronically inflamed tissues continue to generate signals that attract leukocytes from the bloodstream. When leukocytes migrate from the bloodstream into the tissue they amplify the inflammatory response. This chronic inflammatory response can break down healthy tissue in a misdirected attempt at repair and healing.
Your immune system sends out its first responders: inflammatory cells and cytokines (substances that stimulate more inflammatory cells). These cells begin an inflammatory response to trap bacteria and other offending agents or start healing injured tissue.
Inflammation is part of the body's response to infection and tissue damage, and it is crucial to the healing process.
As inflammation progresses, however, it begins to damage your arteries, organs and joints. Left unchecked, it can contribute to chronic diseases, such as heart disease, blood vessel disease, diabetes, obesity, cancer, Alzheimer's disease and other conditions.
Clinically, acute inflammation is characterized by 5 cardinal signs: rubor (redness), calor (increased heat), tumor (swelling), dolor (pain), and functio laesa (loss of function) (Figure 3-1).
Inflammation starts within the first hour or two after injury, peaks within 1-3 days but lasts at least a couple of weeks. This phase is when you will experience swelling and some heat around your injury. This is entirely normal and a natural part of your body's tissue healing process.
Chronic inflammation begins without an apparent cause — and doesn't stop. The immune system becomes activated, but the inflammatory response isn't intermittent, as it is during an acute injury or infection. Rather, it stays on all the time at a low level.
Chronic inflammation is also referred to as slow, long-term inflammation lasting several months to years. Generally, the extent and effects of chronic inflammation vary with the cause of the injury and the ability of the body to repair and overcome the damage.
Based on visual observation, the ancients characterised inflammation by five cardinal signs, namely redness (rubor), swelling (tumour), heat (calor; only applicable to the body' extremities), pain (dolor) and loss of function (functio laesa).
Five cardinal signs characterize this response: pain, heat, redness, swelling, and loss of function.
This type of stimulation–response activity generates some of the most dramatic aspects of inflammation, with large amounts of cytokine production, the activation of many cell types, and in fact the four cardinal signs of inflammation: heat, pain, redness, and swelling (1).
Acute inflammation should go away within a few days, unless it's left untreated. If you're experiencing any signs of long-term inflammation, make an appointment with your doctor. They can run some tests and review your symptoms to see if you need treatment for any underlying conditions.