Polyarthritis

Polyarthritis - also known as chronic polyarthritis or rheumatoid arthritis - is one of the inflammatory autoimmune diseases. Not only in Germany it is well known because of its wide distribution. It also occurs quite frequently worldwide. If the joint pain occurs without inflammation, it is arthralgia, not arthritis.

In polyarthritis, several joints are affected by joint inflammation. In addition, organs, bursae and tendon sheaths can also be affected. If only one joint is inflamed, it is a monoarthritis, in two to four joints it is an oligoarthritis. The “poly” means that several joints are always affected by inflammation - from five or more affected areas one speaks of polyarthritis.

Although the disease is often diagnosed in senior citizens, younger people can also develop polyarthritis. In the age between 40 and 60 years the risk of disease is particularly high. In Germany, approximately 700,000 people suffer from the autoimmune disease, almost one percent of the total population.

The joint disease can cause great pain, severe swelling and redness. For example, fingers and hands are difficult to move. Even running or bending the knees becomes a torture. The cause of the symptoms is inflammation. If the arthritis is acute, the inflammation will subside after days or a few weeks. Only after a period of six weeks is the disease known as chronic arthritis.

The exact causes of polyarthritis have not been clarified until today. Various theories regarding the origin of the disease are being researched. On the one hand, genetic factors and heredity are thought to play a role, as polyarthritis is more common in families.

On the other hand, the disease can be a side effect of infectious diseases such as tuberculosis, Ross River fever, Morbus Crohn or Morbus Whipple. Acute polyarthritis cannot be ruled out even in cases of infection with hepatitis B, hepatitis C, HIV, Epstein-Barr and rubella. It can be triggered by a parvovirus B19 infection, especially in young women who have frequent contact with small children. The disease occurs less frequently in ulcerative colitis.

As it is an autoimmune disease, the body’s own immune system attacks its own cells. It is therefore a faulty reaction of the immune system, which should normally protect us from outside intruders. Many patients carry the HLA gene DR4/DRB1, while only 25 percent of the healthy population has this gene variant. The HLA, human leukocyte antigen, marks cells as endogenous or exogenous, so that the immune system knows which structures to attack. If this differentiation does not function correctly and own cells are marked as foreign, the immune system attacks the body’s own structures. This is called an autoimmune reaction. In case of polyarthritis, the cartilages are particularly affected. This is where inflammation develops, which is responsible for the symptoms.

As the immune system is active throughout the body, soft-tissues or organs can also be affected - this is where there is the biggest difference to rheumatism, as this disease only affects joints. Also, in the case of arthrosis, the cause lies elsewhere: The joint inflammation is caused by wear and tear. In case of polyarthritis, the wear and tear only result from the inflammation.

It is also discussed which substances have a conducive effect on the development of polyarthritis - such as tobacco smoking. According to the latest findings, pro-inflammatory hormones, the so-called cytokines, could also contribute to the disease.

When and why and in what form polyarthritis breaks out is still being researched. In addition to environmental influences such as allergies or infections, the immune system is crucial here, as it turns against its own body and produces cytokines that cause pain and swelling as well as signs of wear in the joints.