Reactive Arthritis – Symptoms and Inflammatory Joint Pain Following an Infection

The exact mechanisms leading to reactive arthritis (ICD code: M02) are still unclear. Researchers have now detected certain bacteria in the synovial fluid or synovial membrane of patients with reactive arthritis. It is therefore believed that pathogens that are no longer multiplying, or components of these pathogens, remain in the joint and trigger inflammation there as “foreign substances.”

A specific host factor, known as HLA-B27, plays a key role in this process. It is detectable in 65 to 97 percent of patients with reactive arthritis. People with HLA-B27 in their blood have a fivefold higher risk of developing reactive arthritis than HLA-B27-negative individuals.

This innate tissue characteristic influences the immune response and contributes to the development of reactive arthritis.

The video shows the development of arthritis with the destruction of cartilage and bone in the knee joint:

Reactive arthritis is widespread worldwide. In Germany, the prevalence is at least 0.05 percent, meaning that 50 out of every 100,000 residents develop reactive arthritis.

Men and women are affected with roughly equal frequency. The majority of patients are under 40 years of age.

Reactive arthritis usually occurs a few days to weeks after the triggering infection. Typical symptoms of such infections may include, for example,

• a burning sensation when urinating,
• frequent urination,
• a burning sensation and discharge from the urethra or vagina,
• diarrhea,
• a sore throat or cough

. However, these infections can be very mild and may not always be noticeable at all.

Joint pain as the primary symptom

Joint pain is the primary symptom of the disease itself. Symptoms can range from mild joint pain (arthralgia) to severe joint inflammation (arthritis). Arthritis is present when joint pain is accompanied by joint swelling and warmth.

Most often, the large joints of the lower extremities are affected, namely

• the hip joint,
• knee joints, and
• ankles.

The shoulder, elbow, or wrist joints are rarely affected. Only in exceptional cases are small joints (finger and toe joints) involved.

Generally, only one or a few joints are affected, most often a knee or ankle joint. It is rare for multiple joints to be inflamed at the same time. Sometimes the inflammation “jumps” from one joint to another.

So-called polyarthritis—that is, inflammation of many joints at the same time, as seen in other rheumatic diseases—is very rare.

Most often, the large joints of the lower extremities are affected by reactive arthritis © freshidea / Fotolia

Additional Symptoms

In later stages of the disease, deep-seated lower back pain may develop. This indicates inflammation of the sacroiliac joints (SI joints).

Other typical symptoms include inflammation in the area of

• tendon insertions (e.g., the Achilles tendon),
• tendons, or
• tendon sheaths.

Sometimes an entire finger or toe becomes swollen. This is referred to as a “sausage finger” or “sausage toe.” Muscle pain may also occur.

Symptoms can also appear on the skin and mucous membranes, such as scaly skin lesions. These are particularly noticeable on the palms of the hands and soles of the feet and resemble psoriasis.

Occasionally, painful, reddish-bluish nodules are present in the area of the ankles and lower legs (erythema nodosum).

Reactive arthritis may be associated with

• urethritis,
• inflammation of the external and internal genital organs (balanitis, prostatitis), or
• cystitis

.

During the course of reactive arthritis, eye inflammation may occur, such as

• inflammation of the conjunctiva (conjunctivitis),
• inflammation of the cornea (keratitis), or
• the iris (iritis/iridocyclitis).

Characteristic symptoms in these cases include

• sensitivity to light,
• pain,
• a burning sensation,
• redness, and
• possibly visual disturbances.

Reiter’s syndrome is a special form of reactive arthritis. It is defined as the simultaneous occurrence of joint inflammation, urethritis, and conjunctivitis.

If a young adult has inflammation in one or a few large joints, reactive arthritis may be the cause.

As part of the medical history, the doctor asks the patient about their past medical history. It is important to determine, for example, whether there has been

• a bladder or urethral infection,
• diarrhea, or
• a respiratory tract infection

. If so, the diagnosis can be made relatively quickly. However, some infections may have gone unnoticed. Another important clue in diagnosing reactive arthritis is the detection of antibodies against the causative pathogen. When an infection occurs, the body produces antibodies that are usually detectable in the blood.

Various testing methods are therefore used to detect antibodies against potential pathogens that trigger reactive arthritis.

In addition, the HLA-B27 marker as well as general inflammatory markers such as erythrocyte sedimentation rate and C-reactive protein (CRP) are measured. Ultrasound and X-ray examinations of the affected joints can determine the extent of the inflammation.

Symptoms can range from mild joint pain to severe joint inflammation. Treatment must therefore be tailored to the specific symptoms.

For drug therapy, corticosteroid-free antirheumatic drugs such as

• diclofenac,
• indomethacin, or
• ibuprofen

. In addition to their pain-relieving effects, these medications also have anti-inflammatory properties. As a result, symptoms resolve in most patients receiving this treatment.

Not all cases of reactive arthritis respond adequately to corticosteroid-free antirheumatic drugs. In such cases, short-term treatment with cortisone may be necessary. Cortisone is a very potent anti-inflammatory hormone produced naturally by the body. Cortisone can also be injected directly into the inflamed joint, provided that a bacterial joint infection has been ruled out beforehand.

If the eyes are affected, particularly in cases of iritis (inflammation of the iris), an ophthalmologist must be consulted. Only immediate treatment can prevent subsequent vision problems.

If the pathogen causing the reactive arthritis—such as chlamydia—has been successfully identified, a short course of antibiotic therapy is prescribed. Since chlamydia is transmitted through sexual contact, the partner must also be treated to prevent reinfection. Although antibiotics have no effect on the current arthritis, they serve to eliminate the pathogen at the site of entry, thereby reducing the risk of future relapses.

In some cases, chronic arthritis may develop. This means that the symptoms persist for an extended period. In such cases, treatment with disease-modifying antirheumatic drugs (DMARDs) such as sulfasalazine or methotrexate may be necessary.

In addition to drug therapy, physical measures such as

• cold therapy (cold air, cryopacks),
• passive range-of-motion exercises,
• heat therapy, or
• ultrasound

can help alleviate symptoms.

Reactive arthritis is not a life-threatening condition. Although the onset can be dramatic, it usually resolves on its own and generally does not cause permanent joint damage.

The average duration of the disease is 6 months. However, in about 20 to 40 percent of patients

• chronic arthritis,
• arthralgia,
• tendon problems, or
• relapses

. Patients who, in addition to arthritis, also had inflammation of the urinary and genital organs or eye involvement are particularly affected by this.

Sometimes, even years after reactive arthritis, there is still a certain “sensitivity to weather changes” in the joints and spine.

What is reactive arthritis?

Reactive arthritis is an inflammatory condition classified as a rheumatic disease that develops following a bacterial infection. Reactive arthritis is joint inflammation that often occurs after an infection of the urinary and genital tracts or the intestines. Typical pathogens include Chlamydia trachomatis or other bacteria.

What are the symptoms of reactive arthritis?

Typical symptoms of reactive arthritis include joint pain, swelling, redness, and inflammation in the large joints of the lower extremities. In addition, urethritis, conjunctivitis, skin lesions, balanitis, or keratoderma blennorrhagicum may occur. Some patients develop deep-seated lower back pain or discomfort during urination.

How is reactive arthritis diagnosed?

Reactive arthritis is diagnosed based on symptoms, a physical examination, and the detection of possible pathogens. It is important to first rule out a bacterial joint infection. Testing for HLA-B27 is often performed as well, since this marker is detectable in many patients with reactive arthritis.

How is reactive arthritis treated?

NSAIDs are usually used to treat reactive arthritis in order to relieve inflammation and pain. In cases of chronic arthritis, treatment with disease-modifying antirheumatic drugs (DMARDs) such as sulfasalazine or methotrexate may be considered. In addition, short-term treatment with cortisone may be necessary, especially when inflammation affects multiple joints simultaneously.

Is the prognosis for reactive arthritis good?

The prognosis is often favorable, as reactive arthritis usually presents acutely and can improve within a few months. In some cases, however, the condition may progress to a chronic form or develop into polyarthritis. HLA-B27-positive patients, in particular, are at increased risk of prolonged symptoms.