Inflammation is part of the immune system response in the body. Older people who have been apparently "healthy" in the past often develop inflammation for no obvious reason. Some long term change in the body reaches a critical point; the auto-immune system is triggered, and your body attacks itself. 
Homeostasis has failed to protect us, probably because it's been "set" at a faulty point for a long time.
Cardio Vascular Disease
Since saturated fats and cholesterol are NOT the cause of cardio vascular disease, the question about a cause is open. But inflammation is now the chief suspect.
Perhaps chronic low intensity irritation of the arterial vessels over a very long time, causes irritation that is finally resolved by the building of plaque over the irritation to protect the arterial wall.
Usually, those plaques cause no problem, unless the blood vessel is suddenly severely constricted, or unless the plaque begins to break down, releasing particles that may block the blood flow in some part of the body.
Inflammation: Causes, Symptoms and Treatment
Irritation
The normal function of the body tissues is adversely stimulated. The immune system tries to respond.
Discharge
If there is some infection the immune system tries to expel the problem. The infection might be wrapped in mucus and expelled as pus. Or a wound might weep a fluid trying to remove the infection.
If you have a poisoning of some kind, that might travel in the blood stream to many parts of the body.
Acute Inflammation
Generally severe swelling, perhaps so great that movement of a joint becomes difficult.
Perhaps the formation of an ulcer on the site of a simple wound.
A doctor might treat an infection with an antibiotic.
Treatments
There is dispute about how best to treat inflammation, since we understand that it's a healing process.
So one response is to enable or encourage it expecting that the body knows how best to deal with this problem.
What happens when you have an inflammation
Many different immune cells can take part in an inflammation. They release different substances, the inflammatory mediators. These include the tissue hormones bradykinin and histamine. They cause the narrow blood vessels in the tissue to expand, allowing more blood to reach the injured tissue. For this reason, the inflamed area turns red and becomes hot.
More defense cells are also brought along with the blood to the injured tissue, to help with the healing process. Both hormones can also irritate nerves, and cause pain signals to be sent to the brain. If the inflammation hurts, you usually favour the affected part of the body.
The inflammatory mediators have yet another function: they increase the permeability of the narrow vessels, so that more defense cells can enter the affected tissue. The defense cells also carry more fluid into the inflamed tissue, which is why it often swells up. After this, fluid is transported out of the tissue once again a while later and the swelling disappears again.
The mucous membranes also release more fluid during inflammation. This happens, for example, when you have a stuffy nose and the nasal mucous membranes are inflamed. Then the nasal secretions can help to quickly flush the viruses out of the body.
But possibly that might be dangerous for some people, or there might be a broken bone for instance, and active intervention is advisable. E.g. Acute appendicitis.
Dr Stephen Phinney on Inflammation
The body's general response
If the inflammation is severe, it may cause general reactions in the body. This may include the following signs and symptoms:
General symptoms of feeling sick, exhaustion and fever: These symptoms are a sign that the immune defense is very active and needs a lot of energy, which may be lacking for other activities. If the rate of metabolism is higher due to a fever, more defense substances and cells can be produced.
Changes in the blood such as an increased number of defense cells.
A very rare but dangerous complication of an inflammation is called sepsis. Sepsis may occur if bacteria multiply quickly in a certain part of the body and then suddenly enter the bloodstream in large quantities. This can happen if the body does not succeed in fighting the inflammation locally, the pathogens are very aggressive, or the immune system is severely weakened.
Chills, feeling very ill, and very high fever can also be signs of blood poisoning. If blood poisoning is suspected, medical assistance is urgently needed.
Inflammations can also cause chronic diseases
An inflammation is not always a helpful response of the body. In certain diseases the immune system fights against its own cells by mistake, causing harmful inflammatory responses. These include, for example:
Rheumatoid arthritis, where many joints throughout the entire body are permanently inflamed Psoriasis, a chronic skin disease like long lasting hives.
Inflammations of the bowel like Crohn's disease or ulcerative colitis
These diseases are called chronic inflammatory diseases, and can last for years or even a lifetime in varying degrees of severity and activity.
