Reactive Arthritis

Question 1

Define Reactive Arthritis

Answer 1

Sterile inflammation in joints following infection, especially urogenital and gastrointestinal infections

Is a seronegative spondyloarthropathy

Question 2

Aetiology of Reactive Arthritis

Answer 2

Urogenital infection: chlamydia trachomatis (60%)
Gastrointestinal infections: salmonella, shigella, campylobacter, yersinia, E. Coli

Infection activates the immune system -> autoimmune reaction involving the skin, eyes and joints

Question 3

What is Reiter’s syndrome

Answer 3

Reactive arthritis, urethritis and conjunctivitis

Question 4

Risk factors for Reactive Arthritis

Answer 4

Immunosuppression e.g. HIV, Hep C
HLA-B27 (70-80%)
Male sex
Preceding infection
Younger adults (20-40)

Question 5

Symptoms of Reactive Arthritis

Answer 5

Symptoms 1-4 weeks after an initial infection

1. Arthritis
   Asymmetrical | Oligoarthritis (<5 joints) | typically lower limbs

2. Enthesitis 
Heel pain (achilles tendonitis) | swollen fingers (dactylitis) | painful feet (plantar fasciitis)

3. spondylitis
   Sacroliitis -> low back pain | spondylitis

Extra-articular:
Enthesopathy
Skin inflammation (psoriasis-like rash on hands and feet, circinate balanitis)
Ocular: sterile conjunctivits
Genito-urinary: sterile urethritis -> burning/stinging on urination

Question 6

Signs of Reactive Arthritis on examination

Answer 6

Arthritis: Asymmetric, oligoarthritic, often affecting the lower extremities, sausage fingers

Conjunctivitis: Red eye, painful eye

Oral ulceration: usual painless

Skin: Circinate balanitis, psoriasis-like rash, keratoderma blennorrhagia (brownish-red macules, vesiculopustules + yellow/brown scales on foot

Other: Fever, nail dystrophy, hyperkeratosis or onycholysis

Question 7

Investigations for Reactive Arthritis

Answer 7

Mainly clinical diagnosis

Stool/urethral swabs: negative
Urine: screen for chlamydia trachomatis

CRP/ESR: raised
HLA-B27 testing
Antibodies (ANA, Rheumatoid-factor): negative
Serology: ?HIV or Hep C

X-ray: sacroiliitis or enthesopathy (erosion at sight of insertion)
Arthrocentesis and synovial fluid analysis: negative (exclude septic arthritis + gout)