Reactive Arthritis

Snapshot

• A 22-year-old man presents to his primary care physician’s office due to pain in his knee, dysuria, and eye discomfort and discharge. Medical history is significant for a sexually transmitted infection due to Chlamydia approximately 1 month ago. On physical exam, there is conjunctivitis, left-knee swelling and tenderness, and urethral discharge.

Introduction

• Clinical definition
  • a systemic inflammatory disorder that results from following an extra-articular infection (e.g., sexually transmitted infection and gastroenteritis)
    • typically results after 1-6 weeks after the infection
    • formerly known as Reiter syndrome
    • classic triad is
      • urethritis
      • conjunctivitis
      • arthritis
• Epidemiology
  • demographics
    • age
      • 20-40 years of age
    • sex
      • following a genitourinary infection, it is more common to develop reactive arthritis in men
      • affects men and women equally a gastrointestinal infection
  • risk factors
    • HLA-B27 positivity 
• Etiology
  • genitourinary pathogens
    • Chlamydia trachomatis
  • gastrointestinal pathogens
    • Salmonella enteritidis and typhimurium
    • Shigella
    • Yersinia
    • Campylobacter
• Pathogenesis 
  • unclear
• Prognosis
• most cases spontaneously recover

Presentation

• Symptoms
  • asymmetric joint pain
    • e.g., knee, ankle, and heel
  • eye discomfort
    • in cases of conjunctivitis
• Physical exam
  • conjunctivitis
  • arthritis
    • typically an acute and asymmetric oligoarthritis
  • genital involvement
    • circinate balanitis
    • urethritis
    • cervicitis
• keratoderma blennorrhagicum 

Studies

• Labs
  • complete blood count
    • may demonstrate
      • neutrophillic leukocytosis
  • ↑ C-reactive protein (CRP) and erythrocyte sedimentation rate (ESR)
• Diagnostic criteria
• a clinical diagnosis

Differential

• Ankylosing spondylitis
• Enteropathic arthritis
• Septic arthritis
• Gonococcal arthritis
• Gout
• Pseudogout
• Rheumatoid arthritis

Treatment

• Medical
  • nonsteroidal antiinflammatory drugs (NSAIDs)
    • indication
      • drug of choice for acute phase of reactive arthritis