Intro to Rheumatology Flashcards
Describe fibrous joints including their functional classification.
Synarthroses - Generally allow no movement OR
Amphiarthroses - Allow very limited movement
No space between the bones.
E.g. Sutures in skull, syndesmosis (sheet of connective tissue) in tibia and fibula joint (Ankle)
Describe cartilaginous joints including their functional classification.
Synarthroses - Generally allow no movement OR
Amphiarthroses - Allow very limited movement
Joints in which bones are connected by cartilage.
E.g. Joints between spinal vertebrae.
Describe synovial joints including their functional classification.
Diarthroses - Allow for free movement of the joint.
Have a space between adjoining bones (synovial cavity)
This space is filled with synovial fluid.
Describe the components of a synovial joint.
2 bone ends lined by articular cartilage. Joint cavity containing synovial fluid.
Articular cartilage - 1-3 cell deep lining containing macrophage-like phagocytic cells (type A synoviocyte) and fibroblast-like cells that produce hyaluronic acid (type B synovicocyte) + Type 1 Collagen
Synovial fluid - Hyaluronic acid-rich + viscous fluid
Synovium - Type II collagen + proteoglycan (mainly aggrecan) > Gives a smooth lining to the ends of the bones in the joint.
What is cartilage composed of and describe its blood supply?
Composed of specialised cells (chondrocytes) and ECM: water, collagen, proteoglycans (mainly aggrecan)
Cartilage is avascular (no blood supply)
What is aggrecan?
Proteoglycan that pocesses many chondroitin and keratin sulphate chains.
Characterised by its ability to interact with hyaluronan (HA) to form large proteoglycan aggregates.
What is arthritis?
Disease of the joints
What are the 2 major divisions of arthritis?
Osteoarthritis - Degenerative (Cartilage worn out)
Inflammatory arthritis - Primary problem is inflammation (main type is RA)
What are the pathological changes in OA?
Cartilage worn out, bony remodelling
What is the epidemiology of OA?
More prevalent as age increases.
Previous joint trauma (e.g. footballer’s knees)
Jobs involving heavy manual labour
Describe the onset of OA.
Gradual
Slowly progressive disorder
Which joints are typically affected in OA?
Joints of hand - Distal interphalangeal joints (DIP), proximal interphalangeal joints (PIP), 1st carpometacarpal (CMC)
Spine
Weight-bearing joints of lower limbs - esp. knees and hips, 1st metatarsophalangeal joint (MTP)
What is joint crepitus?
Creaking, cracking grinding sound on moving affected joint - often OA
What are the names of the nodes seen in OA?
Heberden’s Nodes - Osteophytes at the DIP joints are termed.
Bouchard’s Nodes - Osteophytes at the PIP joints are termed.
What are the symptoms and signs of OA?
Joint Stiffness after immobility ('gelling') Joint Pain (worse with activity, better with rest) Joint Instability ('giving way') Joint Crepitus Joint Enlargement e.g. Heberden's Nodes Limitations of range of motion
Heberden’s Nodes (osteophytes at DIP)
Bouchard’s Nodes (osteophytes at PIP)
What features can be be seen on an X-ray (radiographic features) of an OA patient? (Classic findings)
Joint space narrowing (bone contacting bone) > Reflects wearing out of normal cartilage layer.
Subchondral bony sclerosis (increased white appearance on X-ray)
Osteophytes - bone spurs
Subchondral cysts
What is inflammation and what are its 5 cardinal features?
A physiological response to deal with injury or infection. Excessive/inappropriate inflammatory reactions can damage the host tissues.
Manifest clinically as: Redness (Rubor) Swelling (Tumor) Pain (Dolor) Heat (Calor) Loss of function
What are the physiological, cellular and molecular changes that occur in inflammation?
Increased blood flow
Migration of WBCs (leucocytes) into tissues
Activation/differentiation of leucocytes
Cytokine production (E.g. TNF-alpha, IL-1,16 and 17 - Important ones for joint disease)
What are the causes of joint inflammation?
Infection - Septic arthritis, TB
Crystal arthritis - Gout and pseudo-gout
Immune-mediated (autoimmune) - Rheumatoid arthritis, psoriatic arthritis, reactive arthritis, SLE
What causes septic arthritis?
Bacterial infection (usually caused by haematogenous spread)
What are the risk factors of SA?
Immunosuppressed, pre-existing joint damage, intravenous drug use (IVDU)
Why is septic arthritis classified as a medical emergency?
Untreated, septic arthritis can rapidly destroy a joint.
How many joints are usually affected in septic arthritis?
What is the main exception?
1 (mono-arthritis)
Gonococcal septic arthritis - often affects multiple joints (polyarthritis); it is less likely to cause joint destruction.
When should you consider septic arthritis for a patient?
Any patient with an ACUTE painful, red, hot swelling of a joint, especially if there is a fever.
What technique can you use to diagnose septic arthritis?
Joint aspiration (then send sample for urgent gram stain and culture)
What bacteria are commonly responsible for septic arthritis?
Staphylococcus aureus, Streptococci, Gonococcus
How can you treat septic arthritis?
Surgical wash out (lavage) and IV antibiotics
When does crystal arthritis occur?
Results when crystals deposit in the joint triggering an inflammatory reaction.
(2 main types → Gout and pseudogout)