Rheumatology: Osteoarthritis Flashcards
What is the target tissue in osteoarthritis?
Articular cartilage. You should notice atrophy of the articular cartilage and hypertrophy of the contiguous bone.
When should the pain of the affected joint be the worst in osteoarthritis?
At the end of the day. This means that they should feel some stiffness in the morning but it should go away in less than half an hour. It’s a mechanical arthritis.
What are Heberden’s nodes and where are they located?
What about Bouchard’s nodes?
Heberdens nodes are bony enlargements of the distal IP joints. Bouchard’s nodes are boney enlargements of the proximal IP joints.
What are some of the risk factors for osteoarthritis?
- Age (the older you get, the higher the risk)
- Trauma/Previous injury
- Obesity (increased work load on your joints, makes the cartilage decomposition process accelerate)
What’s the difference between primary and secondary OA?
Primary=idiopathic, no known inciting event/disease
Secondary=known events/disease induce OA
What is the most common type of collagen in cartilage?
Type II, makes up 90% of collagen in cartilage.
What role do proteoglycans play in cartilage?
They retain water, which makes up 70% of the total weight of cartilage. Water is key to the absorbent function of cartilage.
What role do chondrocytes play in cartilage, and what goes wrong in OA?
Chondrocytes produce both the constructive (collagen, proteoglycans) and destructive (metalloproteinase) factors of cartilage. In OA, the destructive factors are doing more work than the constructive ones.
What is the most important cytokine in relation to cartilage destruction?
IL-1. It promotes degradation and down-regulates reconstruction of cartilage. TNF alpha plays a similar role to IL-1.
What is the pattern of water content in cartilage in OA?
At the beginning stages of OA the water content will increase b/c the weaving of cartilage is weaker. Eventually the water content will decrease to 50% of the normal level.
Which metabolic diseases are involved in accelerated OA?
Hemochromatosis, Wilson’s disease, and ochronosis.
What genetic factors are thought to lead to OA?
Point mutations in Type 2 collagen, or genetic abnormalities of cartilage in general.
