Clinical - Arthritis Flashcards
Diagram of a typical synovial joint
What are the bones of a synovial joint lined by?
A layer of hyaline cartilage that functions to absorb shock and reduce friction during movement.
What is synovitis?
Inflammation of the synovial membrane
What is inflammatory arthritis?
A chronic autoimmune disease in which your immune system misidentifies your own body tissues as harmful germs or pathogens and attacks them. The result is inflammation of the affected tissues in and around joints.
What happens during inflammatory arthritis / synovitis?
Synovial membrane becomes inflamed and pumps out inflammatory chemicals which creates collection of fluid in joint
What is osteoarthritis?
- Most common form of arthritis, affecting millions of people worldwide. It occurs when the protective cartilage that cushions the ends of your bones wears down over time.
- Most commonly affects joints in your hands, knees, hips and spine.
- Most commonr reason for knee and hip replacements
What happens when bits of cartilage start to flake off in OA? How does this affect synovial membrane?
- Cartilage flakes into synovial lining, causing inflammation within lining of joint –> synovitis
- As synovium becomes inflamed, the bone reacts to low level of inflammation by trying to heal itself –> becomes thicker and bulkier
- Joint physically grows thicker
- Get cysts forming in the subchondral bone –> pain
What is subchondral bone?
The layer of bone just below the cartilage in a joint
Hands of OA
Tends to affect middle and distal joints of fingers –> appear swollen
X-ray of knee with arthritis
- Bone appears white –> due to sclerosis
- Chunkiness and irregularity around edge –> Osteophytes are exostoses (bony projections) that form along joint margin usually due to inflammation
How does OA affect inflammatory markers?
Inflammatory markers and antibodies are normal - no specific blood tests can help diagnose
Key features of inflammatory arthritis?
- Morning stiffness more than 30 minutes
- Raised inflammatory markers (CRP) –> usually
- Definite joint swelling
- Positive blood tests for certain antibodies –> usually
- Inflammatory back pain
- Not just in old people!
Take notes of key differences between inflammatory arthritis and OA
What type of arthritis is rheumatoid arthritis?
Inflammatory arthritis - autoimmune
Key features of rheumatoid arthritis
- F:M 3:1
- Most common age 40-50s
- Joint swelling, heat, pain, morning stiffness
- Small joints of hands and feet
- Other organs can be affected too
- 80% positive Rheumatoid Factor blood test
- CCP blood test
What blood tests can be used to diagnose Rheumatoid arthritis?
- CRP - measures inflammation
- Rheumatoid Factor blood test - Rheumatoid factors are proteins that the immune system produces when it attacks health tissue
- CCP - Anti-CCPs are antibodies also produced by the immune system. People who test positive for anti-CCP are very likely to develop rheumatoid arthritis.