Osteoarthritis and Reactive Arthritis Flashcards
Define reactive arthritis.
Sterile inflammation in joints following infection, especially urogenital and gastrointestinal infections
State a urogenital infection that can cause reactive arthritis.
Chlamydia trachomatis
Give some examples of gastrointestinal infections that are associated with reactive arthritis.
Shigella
Salmonella
Campylobacter
What subset of the population does reactive arthritis tend to occur in?
It occurs mainly in young adults with a genetic predisposition and an environmental trigger
How long after the infection does the reactive arthritis tend to appear?
1-4 weeks
Describe the features of the arthritis in reactive arthritis.
- asymmetrical arthritis
- oligoarthritis (affecting between 2 to 4 joints, less than 5)
- lower limbs more affected
Reactive arthritis can cause enthesopathy. Which entheses are likely to get affected and what symptoms will that cause?
(enthesis is the connective tissue between tendon or ligament and bone)
- Achilles tendonitis
- Dactylitis
- Metatarsalgia (painful feet because of inflammation of the palmar fascia)
What is a very common feature of seronegative spondyloarthropathies?
Sacro-iliitis
State some extra-articular features of reactive arthritis?
- Genitourinary (Sterile urethritis)
- Skin inflammation (Circinate balanitis, Keratoderma blennorhagicum)
- Eye inflammation (Sterile conjunctivitis)
What is the triad of symptoms that can be used to describe reactive arthritis?
Reiter’s syndrome – joint inflammation + urethritis + conjunctivitis
Where can you get spondylitis in rheumatoid arthritis?
At the atlanto-axial joint – there is synovium here
Describe the main differences between rheumatoid arthritis (RA) and reactive arthritis (ReA).
Rheumatoid Arthritis vs Reactive Arthritis
Sex Ratio:
F>M - M>F
Arthritis:
Symmetrical, Polyarticular, Small&Large Joints VS Asymmetrical, Oligoarticular, Large joints
Enthesopathy:
NO - YES
Spondylitis:
NO (Except atlanto-axial joint in cervical spine) - YES
Urethritis:
NO - YES
Skin involvement:
Subcutaneous nodules VS K.blennorhagicum, Circinate balanitis
Rheumatoid factor:
YES - NO
HLA association:
HLA-DR4 - HLA-B27
What is the main danger in septic arthritis?
The bacteria produce metalloproteinases that can rapidly degrade the articular cartilage
What are the main differences between septic arthritis and reactive arthritis?
Septic arthritis has a positive synovial fluid culture
It is treated with antibiotics and may even require joint lavage
Describe the treatment of reactive arthritis.
It usually resolves by itself in 2-6 months
NSAIDs to control pain and symptomatic treatment of extra-articular manifestations
no role for antibiotics
Define osteoarthritis.
Chronic slowly progressive disorder due to failure of articular cartilage that typically affects the hands (especially those involved in the pinch grip), spine and weight-bearing joints (hips and knees)
Which joints are most commonly affected in osteoarthritis?
DIP PIP First metacarpophalangeal joint Spine Knees Hips First metatarsophalangeal joint
What are the names given to the osteophytes found on the hand in osteoarthritis?
Bouchard’s Nodes – PIP
Heberden’s Nodes – DIP
What are some other associations of osteoarthritis?
Joint pain (worse with activity) Joint crepitus (creaking, cracking grinding sound on moving affected joint) Joint instability Joint enlargement (e.g. Heberden’s nodes) Joint stiffness after immobility Limitation of motion
What are some radiographic features of osteoarthritis?
Joint space narrowing
Osteophytes
Subchondral bony sclerosis
Subchondral cysts
Describe the differences between the radiographic features of rheumatoid arthritis and osteoarthritis.
Rheumatoid arthritis and Osteoarthritis have joint space narrowing
RA doesn’t have subchondral sclerosis or osteophytes
There is osteopenia and there are bone erosions in rheumatoid arthritis but not in osteoarthritis
What can osteoarthritis be caused by?
- excessive loading on joints (more apparent in old)
2. abnormal joint components (more apparent in young)
What is the most important component of articular cartilage?
Aggrecan
What is aggrecan made up of?
Chondroitin sulphate – glucuronic acid + N-acetyl galactosamine
Keratan sulphate – galactose + N-acetyl glucosamine
What is a proteoglycan?
Glycoproteins that contain one or more sulphated glycosaminoglycan (GAG) chains
What is special about hyaluronic acid?
It is the only non-sulphated GAG
What are the disaccharides in hyaluronic acid?
Glucuronic acid
N-acetyl glucosamine
How is osteoarthritis managed?
Physiotherapy – strengthening the muscle around the joint improves joint stability
Analgesia – paracetamol, NSAIDs, intra-articular corticosteroid injections
Joint replacement
Weight loss where appropriate
Compare the synovial fluid culture, antibiotic therapy and joint Lavage for septic arthritis and relative arthritis
- synovial fluid culture +ve in septic, reactive is sterile
- ab therapy yes in septic, no in sterile
- joint lavage yes for large joints in septic, no for reactive
How is ReA diagnosed?
- Clinical diagnosis (i.e asymmetrical arthritis)
- Investigations to exclude other causes of arthritis e.g. septic arthritis
Examples of important investigations:
-Microbiology:
Microbial cultures – blood, throat, urine, stool, urethral, cervical
Serology e.g. HIV, hepatitis C
-Immunology
Rheumatoid factor
(HLA-B27)
-Synovial fluid examination
Especially if only single joint affected
Describe the structure of articular cartilage
- Avascular and aneural structure
- Collagen - >90% is type II
- Chondrocytes
- Proteoglycan monomers (aggrecan)
What is the role of HA in synovial fluid?
major component of synovial fluid where it has an important role in maintaining synovial fluid viscosity
What are the cartilage changes in osteoarthritis?
reduced proteoglycan
reduced collagen
chondrocyte changes e.g. apoptosis
What are the therapeutic approaches for osteoarthritis?
Therapeutic approaches not approved in UK
Glucosamine and chondroitin sulphate – commonly taken, but NOT recommended by NICE
future drugs could be aggrecanase inhibitors, cytokine inhibitors etc
What is the difference between ReA and septic arthritis?
ReA is distinct (sterile) from in section in the joints which is septic arthritis
What may reactive arthritis may be first manifestation of?
HIV or Hep C
What family of disease is ReA from?
seronegative spondyloarthropathies