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Flashcards in Osteoporosis Deck (24):
1

Causes of osteoporosis

  1. Menopause - lack of estrogen
  2. Hypogonadism
  3. Vitamin D deficiency
  4. Hyperthyroidism
  5. Coeliac disease
  6. Primary hyperparathyroidism
  7. Monoclonal gammopathy of uncertain significance (MGUS)

2

Diagnostic criteria

  1. Bone Mineral Density using DEXA scan - T
  2. Fragility fracture after the age of 50 

3

Peak bone mass is achieved at what age

40-50 

4

Options for drugs in Osteoporosis

  1. Antiresorptive
    1. Bisphosphantes- Alendronate
    2. Selective oestrogen receptor modulator - Tamoxifen, Raloxifen 
    3. Oestrogen
    4. Calcitonin
    5. RANKL inhibitor - Donesumab 
  2. Anabolic
    1. PTH 

5

Examples of anti resorptive drugs used in osteoporosis

  1. Bisphosphonates : inhibits osteoclast - apoptosis . Alendronate, rerisdronate, etidronate, pamidronate, zolendronate
  2. Raloxifene - estrogen receptor modulator (also called SERMS, selective estrogen)
  3. Denosumab - binds to RANKL

6

Anabolic agent used in osteoporosis

Teriparatide - synthetic parathyroid hormone increases osteoblastic activity

7

DDx for osteoporosis

  1. Osteopenia
  2. Multiple myeloma
  3. Osteomalacia
  4. Chronic kidney disease
  5. Primary hyperparathyroidism
  6. Metastatic bone malignancy
  7. Vertebral deformities
  8. Osteogenesis imperfecta
  9. Hypogonadism
  10. Cushing's syndrome
  11. Rhematoid arthritis
  12. Mastocytosis

8

Two main factors that determine risk of osteoporosis

  1. Peak bone mass 
    1. genetics
    2. ca, diet, exercise
  2. Rate of bone loss 

9

Risk factors for low bone mass

Non-modifiable

  1. Age
  2. Race
  3. Female
  4. Early menopause
  5. Slender build
  6. Family history 

Modifiable

  1. Low Ca intake
  2. Low vit D intake
  3. Oestrogen deficiencyy
  4. Sedentry lifestyle
  5. Smoking
  6. Alcohol
  7. Caffeine
  8. Medication

10

Bone mass and quality in Osteoporosis

  • Loss of bone mass 
  • Reduction in bone quality
    • loss of horizontal struts
    • loss of connectivity
    • conversion of trabecular plates to rods
    • Resorption pits are "stress concentrators"
    • Unfavorable geometry 

11

Definition of osteoporosis

systemic skeletal disease chracterised by low bone mass and micro-architectural deterioriation of bone tissue resulting in increase fragility and risk of fracture 

12

Risk factors for Osteoporotic fracture

Major

  • Personal history of fracture as an adult
  • history of fragility fracture in 1st degree relative
  • low body weight
  • current cigarette smoking
  • >3 months of oral corticosteriod use

Additional 

  • Estrogen deficiency at an early age
  • dementia
  • excessive alcohol use
  • recent falls
  • inadequate physical activity
  • poor health/fragility
  • impaired vision
  • lifelong low Ca intake

13

Investigations for suspected osteoporosis 

  1. X-ray - fracture
  2. Bloods
    1. Bone turnover markers : Ca, PO4, ALP, Osteocalcin (urine = increased turnover), urine hydroxyproline
    2. Bone pathogenic marker : TSH, PTH, Ca, PO4, EUC, Cr, Testosterone, Vitamin D, Serum and urine electrophoresis 
  3. Bone scan - detects osteoblastic activity + new fracture, pagets and metastatic lesions
  4. MRI - new fracture
  5. BMD  diagnosis 
  6. Bone Biopsy 
  7. Bone u/s - not standardised 

14

What is the difference between T-score and Z-score in DXA scan

T score = compared to mean peak bone mass, what is desirable

Z score = compared to age and gender matched controls, what is expected, if bone mass is unusually low 

15

Important risk factors in Fracture risk calculations

Age

BMD

Hx of prior fractures 

16

Difference between the trabecular bone in glucocorticoid induced osteoporosis and osteoporosis

GIOP = generalised thinning of trabeculae

Postmenopausal osteoporosis = breakage of trabeculae 

17

Treatment for glucocorticoid induced osteoporosis (GIOP)

  1. Reduce or replace steriod treatment
  2. Vit D, Calcium
  3. Bisphosphanates 

18

Definition of osteomalacia 

Systemic skeletal disorder of mineralisation of newly formed organic matrix 

In children results in ricket's 

19

What is required for normal bone mineralisation

  • Normal ca and PO4 concentration 
  • Presence of alkaline phosphatae and mature bone matrix
  • Absence of inhibitors - bisphosphonate and aluminium

20

Causes of osteomalacia

  1. Vitamin D abnormality
  • D defciency
  • liver disease
  • renal disease 
  • 1 a- hydroxylase deficiency
  • vit d resistance
  1. Hypophosphateamia
  • x-linked hypophosphatemia rickets
  • autosomal dominant hypophosphatemic rickets
  • autosomal recessive hypophosphatemic rickets
  • excessive klotho
  • oncogenic osteomalacia
  1. Disorder of bone matrix - hypophosphatasia
  2. Inhibitors of mineralisation 
    1. Bisphosphonate
    2. aluminum 
  3. Toxicities
    1. Fluoride
    2. etidronate
    3. perenteral alunium
    4. imatinad
  4. Acidosis 

21

Investigations (findings) of osteomalacia 

  • Low Vit D
  • Hypocalcaemia
  • Hypophosphataemia
  • High PTH
  • Low BMD

22

Treatment of osteomalacia

  • Reversible 
  • Cod liver oils, fish, egg, meat
  • Vit D exposure 

23

Characteristics of Osteitis Deformans

  • Focal skeletal disorder 
  • Accelerated bone turnover
  • disorganised bone formation 
  • high BMD
  • High bone turnover - ALP, urinary hydroxyproline

24

Definition of osteodystrophy

Combination of 

  1. Osteoporosis
  2. osteomalacia
  3. adynamic boen disease - aluminum toxicity resulting in low bone turnover

Occurs in chronic renal failure or ialysis patients