Reactive arthritis (MSK) Flashcards
What is reactive arthritis?
Sterile inflammatory arthritis that occurs after exposure to certain gastrointestinal and genitourinary infections
What family of inflammatory rheumatic diseases does reactive arthritis belong to?
- belongs to the spondyloarthropathy family that also includes psoriatic arthritis, ankylosing spondylitis, IBD-related arthritis and undifferentiated spondyloarthropathy
- they share similar clinical, radiographic and laboratory features e.g. spinal inflammation and association with HLA-B27
Name the bacteria that causes post-STI reactive arthritis.
Chlamydia trachomatis - this form of arthritis is more common in men
What is Reiter’s syndrome?
Post-infectious arthritis, non-gonococcal urethritis and conjunctivitis (classical triad but found only in a minority of cases)
What infections is reactive arthritis associated with?
- GI (diarrhoeal illness) - salmonella, shigella, Yersinia, Campylobacter
- urogenital (urethritis/cervicitis) - chlamydia trachomatis, ureaplasma species
What is the (thought) mechanism of reactive arthritis?
It is thought that initial activation of the immune system by a microbial antigen is followed by an autoimmune reaction that involves the skin, eyes and joints –> typically affects lower limbs 1-4 weeks after urethritis or dysentry
What is reactive arthritis categorised as and why?
Seronegative spondyloarthropathy
- negative for rheumatoid factor
- strong genetic association with HLA-B27
Who does reactive arthritis commonly affect?
Young men
What is usually seen in the history of a patient with reactive arthritis?
History of recent antecedent genitourinary or dysenteric infection 1-4 weeks before onset (symptoms can develop 3-30 days after infection)
What is the typical joint pattern for reactive arthritis?
Usually an asymmetrical oligoarticular arthritis affecting large joints of lower limb (but polyarticular and monoarticular can also occur)
What are the two types of arthritis that reactive arthritis presents with?
- peripheral arthritis - clinical symptoms 1-4wks after onset of infection –> asymmetrical oligoarthritis of larger joints in lower extremity
- axial arthritis - spinal inflammation (sacroiliac joints and lumbosacral spine) = non-specific low back/buttock pain, relieved by exercise (distinguished from mechanical back pain)
What are the clinical features of reactive arthritis?
Can’t see, can’t pee, can’t climb a tree
- asymmetrical arthritis affecting larger joints of LL 1-4 weeks after infection –> painful, warm, swollen, red, stiff joints
- sacroiliitis - lower back pain
- conjunctivitis / uveitis (anterior uveitis = painful red eye)
- urethritis - burning/stinging on urination
- enthesitis and plantar fasciitis - painful heels
- dactylitis (inflammation of digit)
- fever, fatigue, weight loss
- symptoms from preceding infection - diarrhoea, dysuria, urethritis
- skin changes
What skin changes are seen in reactive arthritis? (2)
- circinate balanitis - painless vesicles on the coronal margin of the prepuce (head of penis)
- keratoderma blenorrhagica - waxy yellow/brown papules on palms and soles
What might be seen on examination of a patient with reactive arthritis?
- asymmetrical oligoarthritis of LL
- circinate balanitis
- conjunctivitis (anterior uveitis = painful red eye)
- keratoderma blenorrhagica
- others: nail dystrophy, hyperkeratosis, onycholysis, mouth ulcers, iritis, aortitis (aortic regurgitation)
What can help differentiate reactive arthritis from septic arthritis?
Normal ROM in reactive arthritis + sterile
What can help differentiate reactive arthritis from mechanical back pain?
Pain gets better on activity in reactive arthritis
What are the risk factors for reactive arthritis? (3)
- male
- HLA-B27 genotype
- preceding chlamydia or GI infection
What are the 1st-line investigations for reactive arthritis? (7)
- ESR
- CRP
- antinuclear antibody (ANA)
- rheumatoid factor
- urogenital and stool cultures
- plain x-rays
- arthrocentesis with synovial fluid analysis
What are ESR and CRP like for reactive arthritis?
Elevated (non-specific)
What are ANA and RF like for reactive arthritis?
Negative - done to rule out other conditions
What is HLA-B27 like for reactive arthritis?
Positive
What are urogenital and stool cultures like for reactive arthritis?
Negative unless patients are tested very early after onset of primary infection
What do plain x-rays show for reactive arthritis?
Sacroiliitis (asymmetrical) or enthesitis (especially at Achilles’ tendon) - more common in chronic reactive arthritis
What is seen on arthrocentesis with synovial fluid analysis for reactive arthritis? (4)
- cloudy yellow colour
- culture negative
- normal WBC
- no crystals (rule out gout)
