Bone abnormalities Flashcards

1
Q

What are the functions of bone?

A

Haematopoiesis
Metabolic tissue (mineral buffer, repair damage, quality of bone)
Protective, supportive,
load bearing

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2
Q

If a normal bone is put under excessive force, what would happen?

A

Fracture

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3
Q

If a weak bone was put under normal force, what would happen?

A

Fracture

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4
Q

If a normal bone was put under normal force, what would happen?

A

Nothing! haha (no fracture

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5
Q

What blood tests can be performed to assess bone structure?

A

alkaline phosphatase! (also used in liver) albumin
calcium, phosphate!
vitamin D, parathyroid hormone
U&Es (kidney disease causes abnormal mineral regulation
FBCs

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6
Q

What imaging can be done to assess bone structure?

A

Plain X-ray

Radionuclide scans CT / MRI / ultrasound

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7
Q

Apart from blood tests and imaging, what other methods are there to assess bone structure?

A

Bone biposy and bone density (DEXA scan)

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8
Q

What is a DEXA scan?

A

Dual Energy X-Ray Absorptiometry (Block 4 week 2 CBL case)

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9
Q

What are the two kind of problems you can get with bone abnormalities?

A

Quantity of bone:
Too little - osteoporosis
Too much - osteopetrosis

Quality of bone:
Defective - rickets, osteomalacia and hyperparathyroidism
Change in structure - osteogenesis imperfecta and paget;s disease

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10
Q

How does parathyroid hormone (PTH) link to calcium levels and thus bone density.

A

Parathyroid glands secrete PTH. PTH regulates the level of calcium in the body. Calcium is needed to make bone.

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11
Q

What is osteoporosis?

A

A complex skeletal disease characterised by low bone density and micro-archeitectural defects in bone tissue, resulting in increased bone fragility and susceptibility to fracture.

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12
Q

What bones are most commonly fractured?

A

Vertebrae, femur and wrist

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13
Q

What wider implications can osteoporosis have?

A
Future fractures
Quality of life
Pain
Long term admission
Mortality
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14
Q

When is peak bone mass usually received?

A

around 30 years of age

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15
Q

What factors contribute to getting peak bone mass?

A

Nutrition, physical activity and genetic factors

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16
Q

How can menopause lead to osteoporosis?

A

Decreased serum oestrogen, increased IL-6/1, TNF levels, increased expression of RANK and RANKL, increased osteoclast activity

17
Q

How can ageing lead to osteoporosis?

A

Decreased replicator activity of osteoprogenitor cells, decreased synthetic activity of osteoblasts, reduced physical activity, decreased biologic activity of matrix bound growth factors

18
Q

Name some risk factors of osteoporosis

A

Old age, female, ethnicity, family history, low BMI, nutrition, vit D and calcium deficiency, steroids, post-menopausal, excessive alcohol

19
Q

In a DEXA scan, what does the T-score show?

A

T-score used to compare bone density of patient with that of the average of the people of that age.
T-score more than -1 - normal
less than -1 but above -2.5 is osteopenia
less than -2.5 is osteoporosis

20
Q

What type of pharmacological treatments are available for osteoporosis?

A

Bisphosphonates
SERM
PTH
Denosumab

21
Q

Name the first line treatment of Bisphosphonates for osteoporosis.

A

Alendronic acid

22
Q

What is the MoA of bisphosphonates?

A

Slows the rate of bone remodelling

23
Q

Name a SERM used for osteoporosis and its moa.

A

Raloxifene - moxed antagonist and agonist function (tissue specific)

24
Q

What are the side effects of SERMs?

A

Hot flushes, DVT and stroke

25
How does PTH help in osteoporosis and how is it administered?
Promotes bone production by inhibition of release of calcium from bone. By a SC injection.
26
What is denosumab and how does it work?
Denosumab is a monoclonal antibody, it works by inhibiting osteoclast formation, function and survival. Given by SC injection
27
How are rickets and osteomalacia similar but different?
Different manifestations of same pathological process. Rickets Affects children Defective mineralisation at the growth plate Osteomalacia Affects adults Defective mineralisation of osteoid
28
What is the most common cause of rickets and osteomalacia?
Vitamin D deficiency usually resulting in low calcium (and low phosphate) levels
29
What is rickets?
Rickets is a condition that affects bone development in children. It causes bone pain, poor growth and soft, weak bones that can lead to bone deformities. GROWTH RETARDATION BONY DEFORMITIES
30
Describe osteomalacia.
``` Defective mineralisation of osteoid May be asymptomatic Muscle weakness (proximal) Bone pain Fractures ```
31
What are the statistics for Paget's disease?
Estimated to occur in 1-3% of people over the age of 55 years
32
What is Paget's disease?
Characterised by increased bone turnover Results in overgrowth, bowing, pain, fractures and deformity May be focal or multifocal
33
What investigations would you do if you suspected Paget's disease?
Bloods – Serum Ca, PTH, ALK P X Rays Radionuclide bone scans Bone biopsy if malignant change is suspected
34
What are the treatments for Paget's disease (mainly non-pharma)
``` Walkers, sticks, orthotics Supportive therapy Analgesia if required Bisphosphonates Surgery ```
35
What is osteogenesis imperfecta?
Inherited condition characterised by defective production of type I collagen
36
What does osteogenesis imperfecta affect?
Bone. teeth, sclera, joints, tendons. heart valves and skin