Medical Edge Newspaper Column

Strep Infection Can Trigger Reactive Arthritis

Oct. 29, 2007
Dear Mayo Clinic:
I've been experiencing swollen joints and pain in my shoulders, wrists and fingers. Tests for rheumatoid arthritis were negative. I took a strep test of my blood, and the doctor said that strep was the cause of my joint pain and swelling. I'm taking penicillin and will go back to test my blood again. Can strep bacteria stay in your system and cause joint pain, swelling and stiffness?

Answer:
Although the streptococcal bacteria (known as strep) probably are the underlying reason for your joint pain, swelling and stiffness, they are not directly causing the symptoms. Your condition sounds like reactive arthritis, which some people develop as a result of an infection in another part of the body.

Reactive arthritis differs from rheumatoid arthritis in several ways. First, reactive arthritis is triggered by infection. Rheumatoid arthritis usually doesn't follow infection or any other factor that can be clearly identified as a trigger. Second, unlike rheumatoid arthritis, the inflammation from most forms of reactive arthritis will eventually go away on their own, unless the body is exposed to more of the triggering germ. Finally, the risk of joint damage, which is high with rheumatoid arthritis, is low with reactive arthritis.

Your immune system protects your body from disease and infection by attacking and getting rid of foreign material, such as bacteria, viruses and parasites. In reactive arthritis, your immune system sees similarities between bacteria (in your situation, strep) and components of your body's joints. It attacks the germs and everything else that has similar features, in this case your joint structures. So, actually, your own immune system is causing the joint pain, swelling and stiffness.

Reactive arthritis is an example of an autoimmunue disorder — the immune system inflicts damage on itself by mistake. A similar immune response to strep occurs in people who develop rheumatic fever, a condition that usually involves not only painful, swollen joints, but also chest pain, shortness of breath, a rash, jerky body movements and fever. If you develop any of these signs or symptoms, see your doctor for an evaluation.

In reactive arthritis, viable bacteria are not present in your joints. In rare cases when bacteria enter the joint structure and cause infection — called septic arthritis — severe pain, high fever, chills and low blood pressure can result. Septic arthritis requires prompt medical treatment and, often, hospitalization.

Reactive arthritis can be painful, but it's not as serious as septic arthritis. Usually, treatment involves managing the symptoms with medications that relieve inflammation and stiffness, and taking antibiotics to destroy any remaining bacteria. Your doctor also may recommend physical therapy, such as range-of-motion exercises, to increase your joints' flexibility and reduce stiffness. For most people, signs and symptoms of reactive arthritis come and go, eventually disappearing within six months.

— Thomas Mason, M.D., Rheumatology, Mayo Clinic, Rochester, Minn.