Skeletal Path Flashcards

Question

What is sequestrum and involucrum?

Answer 1

S - fragments of necrotic bone left over in osteomyelitis that need to be removed I - sleeve of new bone made by periosteal osteoblasts around dead infected bone once exudate penetrates cortex and elevates periosteum

Answer 2

Occurs in small percentage of tb Most commonly thoracic and lumbar vertebrae - affected collapse and inf spreads into adjacent bones and soft tissue More destructive than pyogenic osteomyelitis

Answer 3

``` Pain Low grade fever Chills Weight loss Possible scoliosis or kyphosis from vertebral fractures compressing spinal nerves ```

Answer 4

Group of genetic diseases with decreased osteoclast function Sclerosis or hardening of skeleton Bones dense but abnormally brittle and fractures common Can be cured by hematopoietic stem cell transplantation

Answer 5

Thickening of bones can compress cranial nerves | Hematopoiesis moves to spleen and liver - hepatosplenomegaly

Answer 6

Loss of carbonic anhydrase II prevents osteoclasts from acidifying extra cellular environment

Answer 7

Synthesis of type I collagen is defective - defects in alpha 1 and 2 chains Large spectrum of phenotypes from lethal to mild

Answer 8

Osteopenia Brittle bone - fracture common and heal slowly Thin blue sclera, small misshapen teeth, of hearing deficits

Answer 9

Softening of bone caused by defective mineralization Bones weak and prone to fracture from weight bearing Widened seams line trabeculae

Answer 10

Rickets Soft bones as well as overgrowth of growth plates since mineralization of cartilage doesn't occur - line rib cage = rachitic rosary

Answer 11

Commonly secondary to vitamin d deficiency | Partly affected by lack of PTH activity

Answer 12

By the third decade Higher in men than women Higher in blacks than whites

Answer 13

Postmenopausal Increased osteoclast activity - Associated with abrupt loss of estrogen that increases lifespan and reduces lifespan of osteoblasts Trabecular bone lost more quickly - fractures of vertebra and proximal femur predominate

Answer 14

By up regulating Fas ligand, activating apoptosis program in osteoclasts By decreasing sensitivity of mature osteoclasts to RANKL

Answer 15

Increased production of inflammatory cytokines such as IL-7 and TNF - decreases activity of osteoblasts and has antiapoptotic effects in osteoclasts

Answer 16

Senile - Begins around 30 in men and women Decreased osteoblasts activity Slower bone loss than in type I

Answer 17

Cushing and prolonged use of exogenous steroids accelerate bone loss - compromise osteoblasts function and decrease calcium absorption from gut --> stimulates release of PTH that activates osteoclasts Immobilization of limb Periarticular osteoporosis with RA

Answer 18

Basic MCU uncoupled - regions of bone where osteoclasts predominate and others where osteoblasts predominate Classic histologic mosaic pattern

Answer 19

Begins with furious osteoclastic activity producing lytic lesion Followed by profound osteoblasts activity In time lesions become quiescent and leave sclerotic deformed bones that are structurally abnormal and weak

Answer 20

Begins in mid adulthood and increases with age Usually asymptomatic Pain from microfractures most common sign Weight bearing can cause degenerative secondary joint problems in the hips Overgrowth of vertebra can compress spinal nerves

Answer 21

It is asymmetrical Stereotypically affects a few joints severely Produces decreased mobility in fingers, spine, and affected joints Ankylosis typically does not occur

Answer 22

First appears in DIP joint of index finger Spreads gradually to other digits DIP joints distorted by osteophytes called heberden nodules Knees, hips, and vertebra involved as disease progresses No fever or malaise, no prominent inflammation

Answer 23

Uncontrolled loss of extra cellular cartilaginous matrix Loss of aggrecan thought to be primary event ADAMTS 1, 4, 5 capable of degrading aggrecan

Answer 24

Type II collagen - tensile strength Aggrecan - highly hydrated and resists compression Constantly remodeled like bone

Answer 25

Chondrocytes die and articular surface becomes shaggy = fibrillation Underlying bone becomes sclerotic Cracks can form and synovial fluid goes through to form subchondral cysts Eventual all cartilage goes away and bone on bone creates eburnated bone

Answer 26

Dramatically inflammatory Symmetrical Affects small joints Ankylosis occurs

Answer 27

Fever and malaise Symptoms range from sore stiff joints to chest pain or SOB from inflammation of heart and lungs Begins in 3rd or 4th decade of life Starts in PIP joints

Answer 28

In about 1/4 of patients Under skin or in lung or heart Central zone of fibrinoid necrosis surrounded by epithelioid macrophages, lymphocytes, plasma cells

Answer 29

Intimal lining of synovium is hyperplastic and synovium is infiltrated with lymphocytes including cd4 T cells, B cells, macrophages, and plasma cells Macrophages produce inflammatory cytokines Synoviocytes produce proteases, prostaglandins, and cytokines that perpetuate inflammation

Answer 30

Invade joint space forming a sheet or pannus that covers articular cartilage and isolates it from metabolites in synovial fluid

Answer 31

Release of IL-1 and TNFalpha from reactive synovium encourages breakdown of cartilage matrix RANKL from activated lymphocytes stimulates osteoclasts