Doctors sometimes find it difficult to diagnose reactive arthritis because there is no specific laboratory test to confirm that a person has it. A doctor may order a blood test to detect the genetic factor HLA-B27, but even if the result is positive, the presence of HLA-B27 does not always mean that a person has the disorder.
At the beginning of an examination, the doctor will probably take a complete medical history and note current symptoms as well as any previous medical problems or infections. Before and after seeing the doctor, it is sometimes useful for the patient to keep a record of the symptoms that occur, when they occur, and how long they last. It is especially important to report any flu-like symptoms, such as fever, vomiting, or diarrhea, because they may be evidence of a bacterial infection.
The doctor may use various blood tests besides the HLA-B27 test to help rule out other conditions and confirm a suspected diagnosis of reactive arthritis. For example, the doctor may order rheumatoid factor or antinuclear antibody tests to rule out reactive arthritis. (See “Key Words,” page 16.) Most people who have reactive arthritis will have negative results on these tests. If a patient’s test results are positive, he or she may have some other form of arthritis, such as rheumatoid arthritis or lupus.
Doctors also may order a blood test to determine the erythrocyte sedimentation rate (sed rate), which is the rate at which red blood cells settle to the bottom of a test tube of blood. A high sed rate often indicates inflammation somewhere in the body. Typically, people with rheumatic diseases, including reactive arthritis, have an elevated sed rate.
The doctor also is likely to perform tests for infections that might be associated with reactive arthritis. Patients generally are tested for a Chlamydia infection because recent studies have shown that early treatment of Chlamydia-induced reactive arthritis may reduce the progression of the disease. The doctor may look for bacterial infections by testing cell samples taken from the patient’s throat as well as the urethra in men or cervix in women. Urine and stool samples also may be tested. A sample of synovial fluid (the fluid that lubricates the joints) may be removed from the arthritic joint. Studies of synovial fluid can help the doctor rule out infection in the joint.
Doctors sometimes use x rays to help diagnose reactive arthritis and to rule out other causes of arthritis. X rays can detect some of the symptoms of reactive arthritis, including spondylitis, sacroiliitis, swelling of soft tissues, damage to cartilage or bone margins of the joint, and calcium deposits where the tendon attaches to the bone.
Type of Doctor Treats Reactive Arthritis
A person with reactive arthritis probably will need to see several different types of doctors because reactive arthritis affects different parts of the body. However, it may be helpful to the doctors and the patient for one doctor, usually a rheumatologist (a doctor specializing in arthritis), to manage the complete treatment plan. This doctor can coordinate treatments and monitor the side effects from the various medicines the patient may take. The following specialists treat other features that affect different parts of the body.
• Ophthalmologist - treats eye disease
• Gynecologist - treats genital symptoms in women
• Urologist - treats genital symptoms in men and women
• Dermatologist - treats skin symptoms
• Orthopaedist - performs surgery on severely damaged joints
• Physiatrist - supervises exercise regimens