Osteoarthritis

Question 1

What are 4 clinical characteristics associated with osteoarthritis?

Answer 1

1. joint pain and lameness - may be associated with prolonged or certain activities
2. limitation of movement and decreased ROM
3. joint effusion
4. local inflammation

Question 2

In what 4 ways is joint fluid altered in cases of osteoarthritis?

Answer 2

1. reduced proteoglycans
2. altered sizes and aggregation of proteoglycans
3. increased water content
4. imbalance in the synthesis and degradation of matric macromolecules

Question 3

What 4 changes are seen in bone and cartilage in cases of osteoarthritis?

Answer 3

1. collagen fibril disruption
2. loss of articular cartilage
3. sclerosis of subchondral bone
4. osteophyte and enthesiophyte development

Question 4

What are 2 important parts of conservative management of osteoarthritis?

Answer 4

1. regular, limited exercise to develop muscle mass
2. maintain lean and appropriate body weight

Question 5

What is the mainstay of medical management of osteoarthritis? How do they work? What is contraindicated?

Answer 5

NSAIDs - inhibit COX-2 to decrease the production of proinflammatory prostaglandins, inhibit spinal cyclooxygenase activity, and prevent sensitization/stimulation of peripheral nociceptors

steroids

Question 6

What is the greatest concern when treating osteoarthritis with NSAIDs?

Answer 6

GI toxicity –> decreased protective prostaglandins can cause life-threatening perforating GI ulcers

• do NOT use steroids with NSAIDs when treating OA!!

Question 7

What NSAIDs are most commonly used to treat osteoarthritis?

Answer 7

COX-2 inhibitors / mixed inhibitors:

• Carprofen (Rimadyl)
• Firocoxib (Previcox)
• Deracoxib (Deramaxx)
• Meloxicam (Metacam)
• Feldene (Piroxicam)
• Etolodac (Etogesic)
• Tepoxalin (Zubrin)

Question 8

How are corticosteroids used to treat osteoarthritis? How do they work?

Answer 8

delivered into the joint to inhibit production of matrix metalloproteinase activators, like plasminogen activator or plasmin and inhibits proinflammatory cytokine (IL-2, TNFa) production by synovial cells

Question 9

What adverse effects are associated with chronic usage of corticosteroids to treat osteoarthritis?

Answer 9

• inhibits proteoglycan and collagen synthesis = thinning of cartilage and fibrillation
• chances of GI ulceration and perforation increased if used with an NSAID

Question 10

What 3 products are found in the veterinary formulation of glucosamine and chondroitin sulfate? What 3 effects do they have?

Answer 10

Cosequin - glucosamine, chondroitin sulfate, manganese ascorbate

1. provide precursors for synthesis of hyaline cartilage matrix
2. provides glucosamine for the synthesis of glycosaminoglycans
3. provides the cofactor needed for the synthesis of glycosaminoglycans (manganese)

Question 11

What is polysulfated glycosaminoglycan?

Answer 11

Adequan - mixture of highly sulfated glycosaminoglycans that provide a protective effect on cartilage homeostasis in the treatment of OA

Question 12

What is hyaluronan? What 4 effects does it have that makes it helpful in treating osteoarthritis?

Answer 12

large linear glycosaminoglycan that acts as a lubricant and shock attenuator

1. anti-inflammatory
2. interferes with ROS development
3. interferes with chemotaxis of inflammatory cells
4. inhibits degradative enzymes