M02.361 Reiter's disease, right knee

Name of the Condition

• Reiter's disease, right knee (ICD Code: M02.361)

Summary

Reiter's disease, right knee is a form of reactive arthritis affecting the right knee joint, characterized by inflammation, pain, and stiffness. It typically develops following an infection, with symptoms appearing weeks to months after the initial illness. The condition involves immune-mediated joint damage, often accompanied by extra-articular manifestations such as eye inflammation or skin rashes. It is considered a post-infectious complication linked to immune responses triggered by the preceding infection.

Causes

Reiter's disease, right knee is caused by the body's immune response to infections, most commonly bacterial infections of the genitourinary or gastrointestinal tract. The infection triggers an inflammatory reaction that can affect joints, even after the initial infection has resolved. The exact mechanism involves immune complex formation and systemic inflammation, though the precise pathways are not fully understood.

Risk Factors

• History of genitourinary or gastrointestinal infections, such as Chlamydia trachomatis or Salmonella.
• Pre-existing joint conditions or autoimmune tendencies.
• Genetic predisposition to inflammatory arthritis.
• Delayed or inadequate treatment of the initial infection.

Symptoms

• Joint pain, swelling, and stiffness in the right knee.
• Reduced range of motion in the affected knee.
• Possible warmth or redness over the joint.
• Extra-articular symptoms (e.g., eye inflammation, skin rashes) may occur but are not specific to the knee.

Diagnosis

Diagnosis involves a combination of clinical evaluation, patient history (including recent infections), and physical examination of the right knee. Laboratory tests may include inflammatory markers (e.g., ESR, CRP) and tests to rule out infections. Imaging (e.g., X-ray, MRI) can assess joint damage or inflammation. Exclusion of other arthritic conditions is also part of the diagnostic process.

Treatment Options

• Nonsteroidal anti-inflammatory drugs (NSAIDs) to reduce pain and inflammation.
• Physical therapy to maintain joint function and mobility.
• Corticosteroid injections for severe joint inflammation.
• Antibiotics if an underlying infection is identified.
• Immunosuppressive agents in refractory cases.

Prognosis and Follow-Up

Prognosis varies; symptoms may resolve with treatment, but some patients experience recurrent episodes or chronic joint issues. Regular follow-up is important to monitor joint function, manage symptoms, and address any extra-articular manifestations. Early intervention can improve outcomes.

Complications

• Chronic arthritis or joint damage in the right knee.
• Recurrent episodes of inflammation.
• Potential spread to other joints.
• Extra-articular complications (e.g., uveitis, skin lesions) if left untreated.

Lifestyle & Prevention

• Prompt treatment of genitourinary or gastrointestinal infections.
• Safe sexual practices to reduce infection risk.
• Regular exercise to maintain joint flexibility.
• Weight management to reduce knee stress.

When to Seek Professional Help

Seek care if knee pain, swelling, or stiffness persists, worsens, or interferes with daily activities. Immediate attention is needed for severe pain, fever, or signs of infection (e.g., redness, warmth).

Tips for Medical Coders

Document the specific joint (right knee) and any associated extra-articular symptoms. Ensure the code M02.361 is used when Reiter's disease is localized to the right knee. Include details of preceding infections or immune triggers if available to support clinical correlation.