arthritis

Question 1

pathology of osteoarthritis

Answer 1

its a wear and tear disease.
there is altered chondrocyte homeostasis with decrease in proteoglycans and cleavage of collagen type 2 fibres resulting in the degrading of the cartilage at the articular surfaces of the bone

Question 2

what are the pathological changes of OA

Answer 2

fibrillation of cartilage as the altered homeostasis casues chondrocytes to die and cartilage dehydrated, causing articular cartilage to break down and the surface of the cartilage to become frayed
then there is eburnation as the exposed bone rubs, polishing it
this causes sclerosis to iccur as the grinding of the bone results in areas becoming more dense

Question 3

how do we get the subchondral cysts of OA

Answer 3

there are small fractures in the eburnated bone. this results in fluid moving into the space and inflammation ocurring around the fluid.

Question 4

what are the nodes of OA

Answer 4

these are formations of bone out to the side due to the formation of cysts in the subarticular bone

Question 5

what is the pathogenesis of RA

Answer 5

the Self antigen is presented to TH cells which produce cytokines that recruit and activate macrophaes within the synovium.
the activated macrophages produce further cytokines like TNF alpha. TNF alpha which stimulates the proliferation of fibroblasts and chondroblasts. these cells proliferate and secrete proteolytic enzymes that destroy the cartilage creating the chronically inflammed thickened pannus

Question 6

what gene is involved in RA

Answer 6

HLA gene. its alleles encode for MHC receptors that have specific binding sites for self antigen of the synovium.

Question 7

how is bone destroyed in RA

Answer 7

the pannus grows over and erodes the articular bone as there is such a large release of proteolytic enzymes in the tissue.

Question 8

pathogenesis of osteomyelitis

Answer 8

there is spread infection to the bone by a pyogenic bacteria . due to the infection there is a pyogenic inflammatory response. the pus forms within the bone shaft and the increasing pressure compresses the bone and altering its blood supply creating necrosis. the pus is then forced to be below the periosteum.

Question 9

pathogenesis of gout

Answer 9

it is arthritis, so joint inflammation, that is intiated by the deposition of urate crystals within and around the joints. unknown cause most of the time.
the crystals precipitate in the joint, these are monosodium urate and they trigger acute inflammation

Question 10

what is chronic gout

Answer 10

repeated attacks of gouty arthritis causing aggregates of urate and eventually deposition in the synovial membrane. these aggregates are tophi

Question 11

primary vs secondary gout

Answer 11

primary is unknown cause
secondary is caused by conditions that lead to increased production of uric acid or decreased removal