What is Rheumatoid arthritis?

Rheumatoid arthritis

What is rheumatoid arthritis?

If you have rheumatoid arthritis, your joints become painful, stiff and swollen. For some people, their symptoms come and go. But for others, their symptoms slowly get worse over many years.

You may worry about being in pain. You may also worry that your joints will become so damaged that you'll have to stop working. And you may be concerned about how your joints look.

There is no cure for rheumatoid arthritis, but there are treatments that can both ease your pain and prevent your joints from wearing down. These treatments help many people with rheumatoid arthritis live active and happy lives.

Key points for people with rheumatoid arthritis

In rheumatoid arthritis, your

immune system
The immune system is made up of the parts of the body that are devoted to fighting infection. The body is constantly being threatened by infections from things like bacteria, viruses and parasites. The immune system fights these infections in different ways. At the microscopic level, the immune system uses antibodies and white blood cells, which travel in the blood and target infectious agents, such as bacteria. These microscopic parts of the immune system either kill the infectious agent directly, or take it to other parts of the body, like the spleen, where it can be dealt with. The lymph nodes are another important part of the immune system. Within them, white blood cells filter through the foreign material that has entered the blood, to see if there are any infections. When you have a swollen gland during a cold, this is actually a lymph node that is reacting to the infection. Unfortunately, it is possible for the immune system to become confused and to use its destructive powers to target healthy parts of the body. Diseases that result from this type of situation are called autoimmune diseases.

immune system, which normally fights infection, attacks the lining of your joints. This makes your joints swollen, stiff and painful.
The small joints of your hands or feet are usually affected first.
Rheumatoid arthritis usually affects similar joints on both sides of your body.
It is most common after the age of 40.
Doctors can have a hard time diagnosing rheumatoid arthritis because it often starts slowly.
It's important to start treatments early to keep your joints from wearing down.

Your joints

To understand how rheumatoid arthritis affects you, it helps to know something about your joints.

A joint is where two bones meet.

On the outside of a joint are the ligaments. They are strong fibers that keep the bones in place. The fibers around a joint are called the joint capsule.
Inside the joint capsule is the lining of the joint. Doctors call it the synovial membrane. This lining makes a fluid called synovial fluid that keeps the joint moving smoothly, much like oil in a car engine.
The ends of bones in the joint are covered by cartilage. This material is hard and slippery and makes the ends of the bones smooth so that they can move easily.

What happens in rheumatoid arthritis

The body's immune system normally helps to defend us against infections and diseases. But in rheumatoid arthritis, the immune system goes wrong.

A joint is where two bones meet.

In rheumatoid arthritis, your immune system attacks your joints, making them swollen and painful.

As well as attacking and destroying germs like

bacteria
Bacteria are tiny organisms. There are lots of different types. Some are harmful and can cause disease. But some bacteria live in your body without causing any harm.

bacteria and

viruses
Viruses are microbes (tiny organisms) that need the cells of humans or other animals to exist. They use the machinery of cells to reproduce. Then they spread to other cells in the body.

viruses, your immune system attacks your joints. This makes your joints swell and become painful.

Over many years, this can make your joints lose their shape and stop working properly.

Source:
National Institute of Arthritis and Musculoskeletal and Skin Diseases (NIAMS).
Questions and answers about arthritis and rheumatic diseases.
Available at www.niams.nih.gov (accessed on 6 March 2009).

¹.

Why me?

We don't know why some people get rheumatoid arthritis. But scientists think that it happens more often in people who have particular

genes
Your genes are the parts of your cells that contain instructions for how your body works. Genes are housed on chromosomes, structures that sit in the nucleus at the middle of each of your cells. You have 23 pairs of chromosomes in your normal cells, each of which has thousands of genes. You get one set of chromosomes, and all of the genes that are on them, from each of your parents.

genes.

Many scientists think that a virus may cause rheumatoid arthritis. But they think you have to have certain genes to be affected by the virus.

Source:
Silman AJ.
Rheumatoid arthritis.
In: Silman AJ, Hochberg MC, eds. Epidemiology of the rheumatic diseases. Oxford Press, Oxford; 2004.

² The research is still in an early stage and scientists haven't proved this yet.

Certain things make you more likely to get rheumatoid arthritis. These are called risk factors.

Here are the risk factors for rheumatoid arthritis.

Family history and genes: Rheumatoid arthritis can sometimes run in families. But if you have a close relative with rheumatoid arthritis, it does not mean you will definitely get the disease.

Source:
Winchester R, Dwyer E, Rose S.
The genetic basis of rheumatoid arthritis: the shared epitope hypothesis.
Rheumatic Diseases Clinics of North America. 1992; 18: 761-783.

³
Being a woman: Rheumatoid arthritis is almost three times more common in women than in men.

Source:
Lawrence RC, Helmick CG, Arnett FC, et al.
Estimates of the prevalence of arthritis and selected musculoskeletal disorders in the United States.
Arthritis and Rheumatism. 1998; 41: 778-799.

⁴ We don't know why this is, but researchers think that it may have something to do with the effects of female

hormones
Hormones are chemicals that are made in certain parts of the body. They travel through the bloodstream and have an effect on other parts of the body. For example, the female sex hormone estrogen is made in a woman's ovaries. Estrogen has many different effects on a woman's body. It makes the breasts grow at puberty and helps control periods. It is also needed to get pregnant.

hormones like estrogen.

Source:
Wilder RL.
Neuroimmunoendocrinology of the rheumatic diseases: past, present, and future.
Annals of the New York Academy of Sciences. 2002; 966: 13-19.

⁵
Being middle-aged: People usually get rheumatoid arthritis in their 40s, but you can also get it in your 20s or 30s.

Source:
Centers for Disease Control and Prevention.
Prevalence of arthritis: United States, 1997.
Morbidity and Mortality Weekly Report. 2001; 50: 334-336.

⁶

Sources for the information on this page:

National Institute of Arthritis and Musculoskeletal and Skin Diseases (NIAMS).Questions and answers about arthritis and rheumatic diseases.Available at www.niams.nih.gov (accessed on 6 March 2009).

Silman AJ.Rheumatoid arthritis.In: Silman AJ, Hochberg MC, eds. Epidemiology of the rheumatic diseases. Oxford Press, Oxford; 2004.

Winchester R, Dwyer E, Rose S.The genetic basis of rheumatoid arthritis: the shared epitope hypothesis.Rheumatic Diseases Clinics of North America. 1992; 18: 761-783.

Lawrence RC, Helmick CG, Arnett FC, et al.Estimates of the prevalence of arthritis and selected musculoskeletal disorders in the United States.Arthritis and Rheumatism. 1998; 41: 778-799.

Wilder RL.Neuroimmunoendocrinology of the rheumatic diseases: past, present, and future.Annals of the New York Academy of Sciences. 2002; 966: 13-19.

Centers for Disease Control and Prevention.Prevalence of arthritis: United States, 1997.Morbidity and Mortality Weekly Report. 2001; 50: 334-336.

This information was last updated on Mar 06, 2009

This information is for educational use only, and is not a substitute for prompt professional medical advice. Readers should always consult a physician or other professional for advice and treatment.
© BMJ Publishing Group Limited 2009. All rights reserved.

The information on ConsumerReportsHealth.org should not be viewed as a substitute for a consultation with a medical or health professional. The information is meant to enhance communication with your doctor, not replace it. Consumers Union can not be liable for any loss, injury, or other damages related to your use of this information.

Your use of this information is subject to our User Agreement available at www.ConsumerReportsHealth.org.