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Flashcards in CORTEX biochemistry Deck (59):
1

What is osteoporosis?

Reduced bone mineral density and increased porosity

2

Osteoporosis can be described as a quantitive defect, what does this mean?

The bone is normal but there's not enough of it

3

What does osteoporosis increase your risk of?

Fractures (i.e fragility fractures)

4

Define osteopenia and osteoporosis

Osteopenia - 1-2.5 SDs below mean
Osteoporosis - >2.5 SDs below mean

5

When does loss of bone density begin?

30 y/o

6

Describe physiological loss of bone density and mention the relevance of menopause

Slowdown of osteoblast activity with age
Increased osteoclastic bone reabsorption post-menopause due to reduced oestrogen

7

List the two types of primary bone osteoporosis

Type 1 post menopausal
Type 2 osteoporosis of old age

8

What are the risk factors for post menopausal osteoporosis?

Early menopause
White people
Smoking
Alcohol
Lack of exercise
Poor diet

9

Which types of fractures tend to occur in post menopausal osteoporosis?

Colles fractures
Vertebral insufficiency

10

What are the risk factors for osteoporosis of old age?

Chronic disease
Inactivity
Reduced sunlight exposure (low vit D)
Smoking
Alcohol
Poor diet
White people

11

Which types of fractures tend to occur in osteoporosis of old age?

Femoral neck fractures
Vertebral fractures

12

List the causes of secondary osteoporosis

Corticosteroid use
Alcohol abuse
Malnutrition
Chronic disease (CKD, malignancy, rheumatoid arthritis)
Endocrine disease (cushing's, hyperthyroidism, hyperparathyroidism)

13

How is osteoporosis diagnosed?

DEXA scanning
Normal serum calcium
Normal serum phosphate

14

How is osteoporosis managed?

Calcium supplements
Vitamin D supplements
Biphosphonates
Monoclonal antibody (desunomab)
Strontium

15

How is osteoporosis managed?

Exercise
Diet
Sunlight exposure

16

List some biphosphonates

Alendronate
Risedronate
Etdronate
IV zoledronic acid (once per year)

17

How do biphosphonates work?

Reduce osteoclast reabsorption

18

How does desunomab work?

Reduces osteoclast activity

19

How does strontium work?

Increases osteoblast replication and reduces absorption

20

Why is intranasal calcitonin not used to treat osteoporosis?

Increased cancer risk with no benefit over other treatments

21

HRT is recommended as first line treatment of osteoporosis in post menopausal women. T/F

False - considered if side effects with other medications

22

What are the risks of HRT?

Breast cancer
Endometrial cancer
DVT

23

What is raloxifene? What is the risk of it?

Oestrogen receptor modulator
DVT

24

Osteomalacia is a qualitative bone defect, what does this mean?

Bone quantity is normal but the quality is sub-par

25

What is osteomalacia?

Abnormal soft bones that have not been mineralised due to deficiencies in calcium and phosphorus

26

What is Rickets?

Abnormal soft bones that have not been mineralised due to deficiencies in calcium and phosphorus occuring in CHILDREN

27

What are the causes of osteomalacia and ricket's?

Lack of dietary calcium
Deficiency of vitamin D
Resistance to vitamin D
Phosphate deficiency (increased renal loses)

28

What are the specific pathologies which lead to osteomalacia and ricket's?

Malnutrition
Malabsorption
Lack of sunlight exposure
Hydrophosphateamia
Long term anti-convulsant use
Chronic kidney disease

29

What are the causes of hydrophosphateamia?

Re-feeding syndrome
Alcohol abuse
Malabsorption
Renal tubular acidosis

30

Which inherited renal diseases can be the cause of osteomalacia and rickets?

X-linked hydrophosphateamia
Vitamin D resistant ricket's

31

How does osteomalacia/ricket's present?

Bone pain (pelvis, spine, femur)
Bony deformity
Pathological fractures
Hypocalcaemia

32

Is bony deformity more common in osteomalacia or ricket's?

Ricket's

33

How does hypocalcaemia present?

Paraesthesia
Muscle cramps
Irritability
Fatigue
Seizures
Brittle nails

34

What may be typically seen on a radiograph of someone with osteomalacia or ricket's?

Pseudofractures (looser's zones) of pubic rami, proximal femur, ulna or ribs

35

How does osteomalacia/ricket's present biochemically?

Low calcium
Low serum phosphate
High serum alk phosphatase

36

How is osteomalacia/ricket's treated?

Vitamin D therapy
Calcium supplements
Phosphate supplements

37

What is hyperparathyroidism?

Over activity of parathyroid glands (i.e high parathyroid hormone)

38

What causes primary hyperparathyroidism?

Adenoma
Hyperplasia
Neoplasia

39

What is the result of primary hyperparathyroidism?

High PTH --> hypercalcaemia

40

How does primary hyperparathyroidism present biochemically?

High calcium
High PTH
Phosphate low/normal

41

How does hypercalcaemia present?

Bones (pain)
Stones (renal)
Groans (fatigue, depression)
Myalgia
Nausea
Thirst
Polyuria
Osteoporosis

42

What is secondary hyperparathyroidism?

Overproduction of PTH secondary to hypocalcaemia caused by CKD or vit D deficiency

43

What is tertiary hyperparathyroidism?

Patients with chronic secondary hyperparathyroidism develop a parathyroid adenoma producing ectopic PTH

44

What is usually the cause of chronic secondary hyperparathyroidism?

CKD

45

What bone problems can hyperparathyroidism cause? How are they treated?

Fragility fractures
Brown's tumours/osteitis fibrosa cystica (lytic bone lesions)
Stabilisation

46

How is hyperparathyroidism treated?

Removal of cause (e.g adenoma, cancer, etc)
Treatment of cause (e.g vit D deficiency, etc)

47

How is hypercalcaemia treated?

IV fluids
Biphosphonates
Calcitonin

48

What type of bone changes are caused by CKD? Why?

Secondary hyperparathyroidism causes osteomalacia, bone sclerosis and soft tissue calcification
Reduced phosphate excretion and inability to activate vit D

49

What is Paget's disease?

Chronic bone disease causing thick, brittle and deformed bones

50

How many bones does paget's disease affect? Which bones?

One or two
Pelvis, femur, skull, tibia

51

Which age groups are typically affected by Paget's?

> 55 (increasing age)

52

Which two factors may increase incidence of Paget's?

Viruses (paramyxoviruses)
Genetic defects

53

Describe the pathogenesis of Paget's disease

Increased osteoclast activity (exaggerated vit D response) -->
Increased bone turnover -->
Osteoblasts become more active in a bid to compensate -->
New bone does not remodel correctly -->
Brittle, easily fractured bone

54

What happens if Paget's occurs in ear ossicles?

Conductive deafness

55

How does Paget's disease present?

Asymptomatic until picked up on x-ray
Arthritis
Pathological fractures
Deformity
Pain
High output cardiac failure

56

How does Paget's disease present biochemically?

High alk phosphatase
Normal calcium
Normal phosphate

57

How does Paget's appear on an x-ray?

Enlarged bone with thickened cortices
Thickened trabeculae
Mixed lysis and sclerosis

58

How does Paget's appear on bone scans?

Increased uptake in affected bones

59

How is Paget's treated?

Biphosphonates
Calcitonin (extensive lysis)
Joint replacement
Femoral shaft fractures stabilised with IM nails

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