Lecture 108 Flashcards
What is the most common type of joint disease, and what characterizes it?
Osteoarthritis; progressive cartilage degeneration and mechanical stress on synovial joints.
What is the principal pathogenic mechanism of osteoarthritis?
Biomechanical stress on articular cartilage leading to an imbalance in cartilage synthesis/degradation.
Which enzymes and inhibitors are imbalanced in osteoarthritis?
Matrix metalloproteinases (MMPs) and tissue inhibitors of metalloproteinases (TIMPs).
Name two key morphologic changes seen in osteoarthritis.
Subchondral sclerosis with possible cyst formation, and osteophyte (“bone spur”) formation at joint margins.
Which finger joints form Heberden and Bouchard nodes in OA?
Heberden: distal interphalangeal (DIP); Bouchard: proximal interphalangeal (PIP).
How does joint pain typically behave in osteoarthritis?
Worsens with activity (later in the day), improves with rest.
What causes loose bodies (“joint mice”) in the joint space in OA?
Cartilage fragments that have sloughed off
What do osteophytes look like?
Mushroom-shape bony outgrowths, found in joint margins and associated with OA
Which genetic associations and environmental factors are linked with RA?
HLA-DR4, PTPN22 variants, and triggers like smoking.
What are two key autoantibodies in RA?
Anti-citrullinated peptide antibody (anti-CCP) and rheumatoid factor (RF).
Define pannus in RA.
Inflamed granulation tissue (synovium) that erodes cartilage and bone, potentially causing ankylosis (joint fusion)
Which hand joints are typically spared in RA?
Distal interphalangeal (DIP) joints are usually spared.
What systemic features might accompany RA?
Fever, fatigue, weight loss, and extra-articular manifestations such as rheumatoid nodules or vasculitis.
How does morning stiffness in RA differ from OA?
RA stiffness lasts longer (often >1 hour) and tends to improve with activity.
The autoimmune response in RA is triggered by
CD4+ T-cells
When does juvenile idiopathic arthritis typically present?
Before age 16, lasting at least 6 weeks.
What are common lab findings in JIA?
Leukocytosis, thrombocytosis, anemia, elevated ESR/CRP, ANA positivity.
What treatment approachs are available for JIA.
NSAIDs, steroids, methotrexate, or TNF inhibitors
What clinical presentations are common in JIA?
Daily spiking fevers, salmon-pink macular rash, anterior uveitis
What genetic mutation underlies achondroplasia?
Autosomal dominant gain-of-function mutation in FGFR3.
How does achondroplasia affect bone growth?
Impairs endochondral ossification, causing shortened limbs but normal trunk.
Which bones remain unaffected in achondroplasia?
Bones formed by membranous ossification (e.g., skull, facial bones).
hat is the fundamental defect in osteogenesis imperfecta?
Type I collagen synthesis defect (COL1A1/COL1A2 genes).
