chap 21 - disorders of the bones and joints

Question 1

skeletal system function

Answer 1

reservoir of minerals (calcium and phosphorus), protection, production of blood cells, movement, shape, rigid support

Question 2

structure of skeletal system

Answer 2

bone is connective tissue, all bones have the same basic structure - cortex, trabeculae, and bone marrow

Question 3

cortex

Answer 3

outlayer of compact bone

Question 4

trabeculae

Answer 4

inner spongy layer of the bone

Question 5

bone marrow

Answer 5

spaces between trabeculae consist of fat and blood-forming tissue

Question 6

bone

Answer 6

dynamic living tissue, undergoing remodeling
- strength and thickness depend on activity

Question 7

bone cells

Answer 7

osteoclasts, osteoclasts, osteocytes

Question 8

bone growth

Answer 8

ossification
types: endochondral and intramembranous

Question 9

endochondral ossification

Answer 9

lay down cartilage, laying down of bone, ossification at epiphyseal plate

Question 10

intramembranous ossification

Answer 10

no cartilage phase occurs, typically occurs in flat bones

Question 11

bone density

Answer 11

• amount of mineral per cm/bone
• indicator of fracture risk

Question 12

factors influencing bone mineral density

Answer 12

diet(calcium, vitamin D, K+, magnesium,protein) , physical activity, hormones (calcitonin, parathyroid hormone, estrogen), age, sex

Question 13

signs and symptoms

Answer 13

pain, decreased mobility, deformity

Question 14

symptoms associated with arthritis

Answer 14

joint stiffness and decreased mobility

Question 15

tests

Answer 15

diagnostic modalities
- radiography to visualize fractures and bony abnormalities

Question 16

osteoblasts

Answer 16

secrete the matrix that will help build the bones
b = build

Question 17

osteoclasts

Answer 17

ruffled membrane, causes bone resorption which is breaking down bone

Question 18

osteocytes

Answer 18

cell of the bone, embedded in the matrix of the bone

Question 19

osteoprogenitor

Answer 19

can become any bone cell

Question 20

erythrocyte sedimentation rate

Answer 20

How long does it take for red blood cells to settle in a sample - shows systemic inflammation, increase in systemic inflammation causes the cells to be stickier and settle first, increase of erythrocyte settlement rate (could show arthritis because inflammation is one of the main manifestations of arthritis)

Question 21

achondroplasia

Answer 21

• Plasia = division, chon = cartilage, chondrocytes, a=no → without chondrocyte dividing, important for bone formation, no laying down of cartilage, no laying down of bone
  Leading cause of dwarfism
  Causes mutation in fibroblast growth factor 3 (FGFR3)
• Autosomal dominant
• Majority de novo mutations, de novo = new
  
  • Most common risk is age of the father
    Result in Faulty bone formation
    Impaired growth of extremities and formation of skull bones
• Can lead to stenosis on the spinal cord due to malformation of foramen magnum in occipital bone
  Causes dwarfism with disproportionately short limbs

Question 22

osteogenesis imperfecta

Answer 22

“Brittle Bone” Disease = Thin and delicate bones easily broken
“Imperfect bone formation”
Mutation in genes resulting in abnormal collagen formation
- Collagen is of normal quality but is produced in insufficient quantities
- Collagen is part of the cartilage that is laid down prior to the bone
Autosomal Dominant
Increase susceptibility to bone fractures
May be in utero
Eight Types
- I-VIII
- Different types of collagen
Malformation of fingers and toes
Spinal curvature
Brittle teeth
Blue Sclera - thin because it is a connective tissue disorder and the sclera is connective tissue, so the veins are showing through

Question 23

congenital clubfoot (talipes)

Answer 23

The most common congenital disorder of the legs
Not painful
Multifactorial inheritance - environment and genetic susceptibility
Treatment: manipulation and casts

Question 24

fractures

Answer 24

Any disruption in continuity of bone
Most often caused by
Trauma
Pathologic fracture
Underlying disease of bone
Pain resulting from tearing of periosteum (covering of the bone)
- types: simple, comminuted, compound, pathologic, and greenstick
in order for a fracture to heal
- broken fragments must be close to each other, also must be stabilized
healing process: involves proliferation of
- osteoblasts from fracture margins - lay down new matrix which will be mineralized to make new bone, vascular channels from periosteum
- immature bone and cartilage gradually remodel into mature bone

Question 25

osteomyelitis

Answer 25

Bacterial infection of bone and marrow Organisms gain access to bone via - Spread of infection from somewhere else - Following trauma or surgery to bone itself Manifestation - Fever, local pain and tenderness Diagnosis and treatment - X-ray reveals changes in bone - Antibiotics, possible surgery Complications may include: - Spread of infection - Endocarditis, sepsis Amputation

Question 26

osteoporosis

Answer 26

Multifactorial disease characterized by absolute reduction of total bone mass - Porous bones - Bone histology is usually normal but lacks structural integrity Age related: One third of population >85 have it Women > men; especially after menopause - Men have a slower decline

Question 27

signs and symptoms of osteoporosis

Answer 27

Disease itself has no symptoms Increased risk of fractures - Mortality - Loss of independent living - Decreased Mobility

Question 28

causes of osteoporosis

Answer 28

Primary - Intrinsic to bone itself - Age - age related bone loss (approx. 0.7%/yr) is a normal biological phenomenon - Declining estrogen Secondary - Cortisol excess - Cortisol breaks things down - stress hormone, so people who are under prolonged stress or take cortisol drugs - Increase PTH -Bone resorption

Question 29

risk factors for osteoporosis

Answer 29

Age Ethnicity - caucasian and asian women are more at risk Genetics - Allele for the vitamin D receptor molecule Skeletal frame size - Smaller frame - less bones - increased risk Decreased levels of estrogen and testosterone Decreased activity level Excess intake of phosphorous, alcohol, nicotine Inadequate levels of vitamins D, calcium, K+, or Mg++

Question 30

clinical manifestations of osteoporosis

Answer 30

Vertebral fractures - vertebrae break down over time Lumbar lordosis and kyphoscoliosis - excess curvature Pulmonary embolism may result from overt fractures of the femoral neck, pelvis or spine - Break the bone = bone marrow in the middle gets into the bloodstream and can travel and get lodged in pulmonary vein

Question 31

diagnosis of osteoporosis

Answer 31

Plain radiographs cannot detect osteoporosis until 30-40% of bone mass is loss; thus specialized radiographic imaging techniques needed - Not a very sensitive test Dual energy x-ray absorptiometry (DEXA) - More sensitive, much better at looking at small changes in loss of density Can be used for screening in populations that are at risk

Question 32

treatment of osteoporosis

Answer 32

irreversible -Medication Inhibition of osteoclasts(biphosphonate, boniva, fosamax), estrogen mimetic - don’t want to put women on hormone replacement therapy (evista), synthetic PTH (forteo)

Question 33

osteopenia

Answer 33

BMD is lower than normal - precursor to osteoporosis

Question 34

osteomalacia and rickets

Answer 34

softening of bone - poor mineralization causes - vitamin D deficiency rickets in children and osteomalacia in adults complications - deformity - increased fracture risk

Question 35

scoliosis

Answer 35

abnormal lateral and rotational curvature of spine

Question 36

kyphosis

Answer 36

abnormal forward bending of upper spine - produces hunched back

Question 37

potential causes of scoliosis and kyphosis

Answer 37

arthritis, congenital, osteoporosis, idiopathic

Question 38

complications of scoliosis and kyphosis

Answer 38

impairment of activity, breathing problems, back pain

Question 39

neoplasms of bone

Answer 39

most common = metastatic tumors from prostate, breasts, other organs - hematopoietic (40%) - myeloma, leukemia bone tumor groups (excluding hematopoietic) - bone - cartilage -fibrous - miscellaneous tumors of bone - benign cysts and tumors: osteoma - primary malignant: osteosarcoma

Question 40

osteoma

Answer 40

histology resembles normal bone - generally slow-growing tumors of little clinical significance when they cause obstruction or produce cosmetic problems - asymptomatic, often in facial bones they do not undergo malignant change

Question 41

osteosarcoma

Answer 41

the most common malignant tumor of bone in children - 70% in patients younger than 20 years symptoms - bone pain, progressive enlarging mass, pathologic fractures - more common in males, ends of long bones, metastasis is common

Question 42

symptoms, signs, and tests of the joints

Answer 42

joint stiffness and decreased mobility, pain and inflammation tests: arthroscopy to visualize joint space

Question 43

osteoarthritis

Answer 43

degenerative joint disease, most common - "wear and tear" = disease of old age - affects weight-bearing big joints, small joints of hands and feet classification - primary: cause unknown or multifactorial - secondary: related to another disease

Question 44

etiology of osteoarthritis

Answer 44

cartilage becomes thin, bone surfaces rub against each other - produce bone cysts and osteophytes - little inflammation until advanced stage

Question 45

risk factors of osteoarthritis

Answer 45

increased age, joint trauma, long-term mechanical stress, endocrine disorders, drugs, obesity

Question 46

rheumatoid arthritis

Answer 46

systemic autoimmune disease affecting connective tissues throughout the body, especially the joints - produces chronic inflammation and thickening of synovial membrane - often associated with rheumatoid factor - autoantibody in blood and synovial tissues, produced by B lymphocytes directed against individuals own gamma globulin - not age associated - usually affects small joints of hands and feet

Question 47

clinical course of rheumatoid arthritis

Answer 47

extremely variable - begins with malaise, fatigue and generalized musculoskeletal pain and then joint pain - small points are usually affected first - involved joints are swollen, warm, painful and stiff on arising or following inactivity

Question 48

arthritis: gout

Answer 48

disorders of purine metabolism - disrupts the body's control of uric acid production or excretion - precipitation gout manifests high levels of uric acid in the blood and other body fluids - hyperuricemia can also lead to uric acid kidney stones crystals deposit in CT throughout the body - 50% of the initial attacks occur in the metatarsophalangeal joint of the great toe - heel, ankle, instep, knee, wrist or elbow when these crystals occur in the synovial fluid, the inflammation is known as gouty arthritis

Question 49

contributing factors of arthritis

Answer 49

age, male sex, obesity, high intake of alcohol, red meat, genetic predisposition