Overview

Reiter’s syndrome, now more commonly referred to as reactive arthritis, is a type of inflammatory arthritis that develops in response to an infection in another part of the body, most often the genitourinary or gastrointestinal tract. It typically manifests with a classic triad of arthritis, conjunctivitis (eye inflammation), and urethritis (inflammation of the urinary tract), though not all patients experience all three symptoms simultaneously. Reactive arthritis is considered a systemic autoimmune condition where the body’s immune system mistakenly reacts to a previous infection, causing inflammation in the joints and other areas. While it can affect anyone, it is most common in young adults, particularly males.

Causes

Reactive arthritis is triggered by a bacterial infection, and the condition usually develops within 1 to 4 weeks after the initial infection. Common causes include:

• Genitourinary infections: Infections like Chlamydia trachomatis are the most frequent sexually transmitted cause of reactive arthritis.
• Gastrointestinal infections: Bacteria such as Salmonella, Shigella, Campylobacter, and Yersinia from contaminated food or water can trigger the condition.
• Respiratory infections: Less commonly, infections of the respiratory tract may also lead to reactive arthritis.
• Genetic predisposition: Many patients with reactive arthritis test positive for the HLA-B27 genetic marker, which increases susceptibility to the condition and influences disease severity.

Symptoms

The symptoms of reactive arthritis typically develop shortly after the triggering infection and can affect multiple body systems. Common symptoms include:

• Joint inflammation (arthritis): Pain, swelling, and stiffness, usually affecting large joints like knees, ankles, and feet. The arthritis is often asymmetric (affecting one side more than the other).
• Eye inflammation (conjunctivitis or uveitis): Red, painful eyes with sensitivity to light and blurred vision.
• Urinary symptoms (urethritis): Burning during urination, increased urinary frequency, or genital discomfort.
• Enthesitis: Inflammation where tendons attach to bones, commonly at the heels (Achilles tendon).
• Skin changes: Rashes like keratoderma blennorrhagicum (thickened skin on soles or palms) and circinate balanitis (rash on the genitals) may appear.
• Lower back pain: In some cases, inflammation of the spine or sacroiliac joints can cause lower back or buttock pain.
• General symptoms: Fatigue, fever, and malaise are also frequently reported.

Diagnosis

Reactive arthritis is primarily diagnosed based on clinical history, symptoms, and ruling out other causes of arthritis. Diagnostic steps may include:

• Medical history: Evaluation of recent infections, especially gastrointestinal or genitourinary infections, is crucial.
• Physical examination: Assessment of joint swelling, range of motion, eye redness, and skin changes.
• Laboratory tests:
  • Urine tests to check for sexually transmitted infections like chlamydia.
  • Stool cultures if a recent gastrointestinal infection is suspected.
  • Blood tests for inflammatory markers (ESR, CRP) and HLA-B27 genetic testing.
  • Rheumatoid factor (RF) and anti-CCP antibodies are usually negative, helping differentiate from other rheumatic diseases.
• Joint aspiration: Synovial fluid analysis may be done to rule out other forms of arthritis like gout or septic arthritis.
• Imaging: X-rays or MRI can show joint inflammation or sacroiliitis, particularly in chronic cases.

Treatment

The treatment of reactive arthritis focuses on managing symptoms, treating any underlying infection, and preventing chronic complications:

• Antibiotics: If an active infection like chlamydia is still present, appropriate antibiotics are prescribed.
• Nonsteroidal anti-inflammatory drugs (NSAIDs): These are the mainstay treatment to reduce joint pain and inflammation.
• Corticosteroids: Local steroid injections into affected joints or short-term oral corticosteroids may be used for severe inflammation.
• DMARDs (Disease-modifying antirheumatic drugs): Medications like sulfasalazine or methotrexate may be used in chronic or severe cases to control ongoing inflammation.
• Physical therapy: Exercises to maintain joint function, improve flexibility, and reduce stiffness.
• Eye treatment: Eye drops or systemic medications to manage conjunctivitis or uveitis, often in consultation with an ophthalmologist.

Prognosis

The prognosis of reactive arthritis is generally favorable for most individuals. Many patients experience significant improvement within 3 to 12 months, and the condition often resolves completely. However, a subset of patients (especially those who are HLA-B27 positive) may experience recurrent flares or develop chronic arthritis that requires long-term management. The risk of chronicity increases with severe initial symptoms or frequent recurrences. With early diagnosis, proper treatment of infections, and comprehensive management of symptoms, most individuals with reactive arthritis can lead active and healthy lives with minimal long-term disability.