Rheumatology Flashcards
What is Rheumatology?
The medical specialty dealing with diseases of the musculoskeletal system including:
Joints = where 2 bone meets
Tendons = cords of strong fibrous collagen tissue attaching muscle to bone
Ligaments = flexible fibrous connective tissue which connect two bones
Muscles
Bones
What are the main 2 types of joint disease?
Osteoarthritis
Inflammatory arthritis
How does inflammation manifest?
RED (rubor)
- PAIN (dolor)
- HOT (calor)
- SWELLING (tumor)
- LOSS OF FUNCTION
What physiological changes underpin inflammation?
Increased blood flow
-Migration of white blood cells (leucocytes) into the tissues
-Activation/differentiation of leucocytes
-Cytokine production
E.g. TNF-alpha, IL1, IL6, IL17
What are the 3 main causes of joint inflammation?
Crystal arthritis - gout, pseudo gout
Immune mediated - rheumatoid arthritis, seronegative spondyloarthropathies, connective tissue disease
Infection - Septic arthritis, TB
What happens in gout?
Gout is a syndrome caused by deposition of urate (uric acid) crystals -> inflammation
What is a major risk factor for gout?
High uric acid levels (hyperuricaemia) = risk factor for gout
What are the causes of gout?
Genetic tendency Increased intake of purine rich foods Reduced excretion (kidney failure)
What happens in pseudo gout?
Pseudogout is a syndrome caused by deposition of calcium pyrophosphate dihydrate (CPPD) crystal deposition crystals -> inflammation
What are the risk factors for Pseudogout?
background osteoarthritis, elderly patients, intercurrent infection
What can gout lead to?
Gouty arthritis
Tophi (aggregated deposits of MSU in tissue)
Where does gout typically affect?
metatarsophalangeal joint of the big toe (‘1st MTP joint’) podagra
How does gout present?
Abrupt onset
Extremely painful
Joint red, warm, swollen and tender
Resolves spontaneously over 3-10 days
What investigations are done for gout?
Joint aspiration, synovial fluid analysis
What is the management for gout?
Acute attack – colcihine, NSAIDs, Steroids
Chronic – allopurinol
What are the characteristics of gout crystals under polarising light microscopy?
urate crystals
needle shape
negative Birefringence
What are the characteristics of pseudo gout crystals under polarising light microscopy?
Calcium pyrophosphate dihydrate CPPD crystals
Brick shaped
positive Birefringence
What is the most common immune mediated inflammatory joint disease?
Rheumatoid arthritis
Define Rheumatoid arthritis
chronic autoimmune disease characterised by pain, stiffness and symmetrical synovitis
(inflammation of the synovial membrane) of synovial (diarthrodial) joints
What is the pathogenesis of Rheumatoid arthritis?
Synovial membrane is abnormal in rheumatoid arthritis:
The synovium becomes a proliferated mass of tissue (pannus) due to:
Neovascularisation Lymphangiogenesis inflammatory cells: activated B and T cells plasma cells mast cells activated macrophages
Recruitment, activation and effector functions of these cells is controlled by a cytokine network
There is an excess of pro-inflammatory vs. anti-inflammatory cytokines (‘cytokine imbalance’)
What is the role of TNF-alpha in RA?
The cytokine tumour necrosis factor-alpha (TNFα) is the dominant pro-inflammatory cytokine in the rheumatoid synovium
Its pleotropic actions are detrimental in this setting:
How was TNF-alphas role in RA validated?
arthritis validated by the therapeutic success of TNFα inhibition in this condition
TNFα inhibition is achieved through parenteral administration (most commonly sub-cutaneous injection) of antibodies or fusion proteins