Flashcards in Musculoskeletal System Deck (68):
1
The outer layer of bone is called___________. It makes up __% of the bone mass and is very______and _________
Cortical bone
Makes up 80%
Very dense and compact
2
The inner layer of bone is called ___________ or _________ bone. It is less _______ and _________ than the outer layer
Cancellous or trabecular
Stiff and Strong
3
Joints are composed of 3 parts.......
Fibrous capsule
Cartilage
Synovial Membrane
4
Intramembranous Ossification is a model of __________. It occurs when.......
Bone Formation
It occurs when mesenchymal cells differentiate into osteoblasts which form bone
5
Endochondral Ossification is a model of __________. It occurs when
Bone formation
It occurs when a cartilage model, created by chondrocytes, is converted to bone by mineral deposition
6
What is bone remodeling?
The process by which old bone is resorped and new bone is layed down
7
What are osteoclasts?
Osteoclasts are multi-nucleated cells that resorp bone
They connect to bone via the protein integrin
When attached they become polarised
8
What are osetoblasts?
Active bone forming cells that produce a collagenous bone matrix
9
What is osetoporosis?
A systemic skeletal disease characterized by low bone mass and micro-architectural deterioration of bone tissue. This causes an increased susceptibility to fracture
10
What are the risk factors for osteoporosis
Female Gender
Low Ca intake/absorption
Renal Disease
White/Asian
Sedentary Lifestyle
Alcohol and Drug use
Low body weight
11
What are the 2 major pathogenic processes for osteoporosis?
Poor bone mass acquisition in adolescence
Accelerated bone loss during the 6th decade
12
What causes poor bone mass acquisition?
Hormone deficiencies and malnutrition along with decreased physical activity
13
What causes accelerated bone loss?
Increased activity of osteoclasts without the same increase in osteoblast activity. Bone is being broken down faster than it is being formed
14
What chemicals increase Bone formation?
Growth Hormone
Vitamin D metabolites
Gonadal steroids
15
What chemicals decrease Bone formation?
Glucocorticoids
16
What chemicals increase Bone resorption?
Glucocorticoids
Thyroid Hormone
High doses of Vitamin D metabolites
17
What chemicals decrease Bone resorption?
Calcitonin
Gonadal Steroids
18
What is BDM?
Bone Density Measurement, the lab test for determining if a patient has osteoporosis. Low BDM and many remodeling markers indicate higher incidence of fractures
19
What are some initial tests for osteoporosis?
Blood cell count
Ca and PO4 levels
Kidney and Liver Function tests
TSH, Oestrogen and Testerone levels
20
What are some additional tests undertaken to screen for osteoporosis?
Screening for Hyperparathyroidism
24 hour urine test to rule our hypo/hypercalciuria
Serum Protein electrophoresis to rule out multiple myeloma
21
What is a urinary marker to show bone resorption has occurred?
Collagen cross-link fragments found in urine
22
What is DEXA and what does it stand for?
The most popular BDM test, Dual-Energy X-ray absorptiometry
23
Even though CT scans are more sensitive they aren't used as much to screen for osteoporosis because........
They expose the patient to more radiation
24
What is a T-score?
The result given by DEXA, it is the number of standard deviations above or below the the mean BDM for a given race/gender
25
What factors influence who should be treated for osteoporosis ?
Increasing age
Declining BDM
Prior fractures
Family history of osteoporosis
Risk factors for boneless (hyperparathyroidism, immobilisation etc)
Lots of bone remodeling markers
26
Should you treat a women with osteoporosis and no fractures?
Yes
27
Should you treat a women with osteoporosis and fractures
Yes
28
Should you treat a women with osteopenia and a fracture?
Yes
29
Should you treat a women with osteopenia and no fractures?
No, however, follow up check should be done in 1-3 years
30
What are some overall stratagies for treating osteoporosis?
Increase calcium intake (diet or supplements)
Oestrogen Replacement Therapy
Bisphophonate use
Selective Oestrogen Receptor modulators
Weight bearing excercise
Reduce consumption of drugs and alcohol
31
What do Selective Oestrogen Receptor modulators do?
They inhibit trabecular and vertebral bone loss by blocking the activity of cytokines that cause bone resorption
32
What do bisphosphonates do?
They bind to mineralised bone structures to inhibit osteoclast activity
33
If T-score is greater than -1 do you treat the patient?
No treatment
34
If T-score is between -2.5 and -1 do you treat the patient?
Treat if fracture present
35
If T-score is less than -2.5 do you treat the patient?
Treat regardless of fracture or not
36
The joint capsule is a _______ structure that defines the outer boundary of joints. The ______ of the capsule varies widely depending on the type of joint and the location within a given joint.
Fibrous Structure
Thickness
37
What is the synovial lining? What is it's function?
A thin lining of cells (including macrophages and fibroblasts), one to three cells thick, runs beneath the capsule
Cells produce synovial fluid that enters the joint space and
acts as a lubricant.
It stabilises the joint by acting as an adhesive
38
Cartilage is composed of:
Chondrocytes
Collagen
Proteoglycans
Water
39
In normal cartilage there is a balance of repair and degradation of the _____________?
Cartilage matrix components
40
Cartilage has load bearing properties due to the __________ and the osmotic swelling pressure of ___________
Collagen fiber network
Aggrecan
41
What are the three types of Arthritis?
Osteoarthritis, Rheumatoid Arthritis and Gout
42
What is Osteoarthritis?
Arthritis caused by the breakdown of articular cartilage and characterised by the formation of osteophytes
43
What are the signs/symptoms of OA
Pain with overuse
Morning stiffness
Instability
Loss of Function
Bony Enlargements at the joint
Joint Deformity/Malalignment
44
OA usually affects the ______________?
Weight-bearing joints
45
Describe the 3 step pathogenesis of OA
1. Excessive proteolytic breakdown of cartilage matrix
2. Breakdown products enter the synovial fluid via erosion
3. Synovial cells take up these products causing a chronic inflammatory response
46
What forms at the margins of the joint?
Osteophytes, or bony spurs, these cause the ragged and irregular surface
47
What are the treatment options for OA?
Pain relief is the major treatment, via topical, local injections or oral pain relivers
Surgery is considered if pain is hard to manage and function is heavily impaired
48
What is Arthroscopic Debridement?
The removal of foreign material and damaged cartilage from the joint until healthy tissue is exposed
49
What is an Osteotomy?
Addition of a wedge of bone to the tibiae to realign the knee. It is designed to take the pressure off the area with arthritis. Usually for patients too young for full replacement
50
What is a Total Joint Arthoplasty?
Total joint replacement, prosthetic replaces the joint
51
What is ACI?
Autologous Chondrocyte Injection: Healthy Chondrocytes are removed from the patient, cultured and replaced thereby repairing the cartilage
52
What is Rheumatoid Arthritis?
A chronic inflammatory disease characterized by uncontrollable proliferation of synovial tissue
53
What are the risk factors for RA?
Old Age
Female Gender
Family History
Smoking
Consumption of too much coffee
54
What are the signs/symptoms of RA?
Morning Stiffness
Arthritis in 3 or more areas
Hand Joints involved
Symmetric Arthritis
Rheumatoid Nodules
Positive test for Serum Rheumatoid factor
Radiographic Changes
55
What causes RA?
Unknown, may be an interaction between genes and the environment
56
Joint damage in RA starts with proliferation of ____________ and ___________ after a triggering incident, possibly __________ or infectious
Synovial Macrophages and Fibroblasts
Autoimmune
57
Blood vessels in joint affected by RA become __________ with small clots or _____________
Occluded with small clots or inflammatory cells
58
Early diagnosis is critical in treating RA as joint destruction occurs within ____________ after onset of symptoms
a few weeks
59
What are some drugs that are used to treat RA?
NSAIDs (Non-Steroidal Anti-Inflammatory Drugs
Corticosteroids
DMARDs (Disease-Modifying Antirheumatic Drugs)
TNF inhibitors (Tumour Necrosis Factors)
60
What is a Synovectomy?
A type of surgery used to treat RA by removing diseased tissue
61
What is Gout?
A disease resulting from the deposition of urate crystals caused over production or under excretion of uric acid
62
The diagnosis of gout depends on the identification of ______________ in the joints, tissue or body fluid
Uric acid crystals
63
What are the characteristics of acute gout?
Attacks are usually mono-arthritic (affect 1 joint)
Usually affect lower extremities
Mainly Podagra (Gout in big toe)
64
What is Uric acid?
The end product of purine metabolism, it has no physiological role.
65
What is Hyperuricemia?
Uric acid levels of 420 umol L or higher, it is a risk factor for developing gout
66
Gout may be associated with __________ and ___________, therefore examination of the cardiovascular and renal system are essential.
Hypertension and Renal failure
67
The diagnosis of gout is confirmed by the presence of ______________ and intracellular _______________ in the synovial fluid taken from the affected joint
Polymorphonuclear leukocytes
Mono-sodium urate crystals
68