Osteoperosis and Osteomalacia

Question 1

what is osteoporosis?

Answer 1

reduction in density of the bones.

Question 2

what is osteopenia?

Answer 2

a less severe reduction in bone density than osteoperosis- less strong so more prone to fractures

Question 3

risk factors for osteopenia

Answer 3

Older age
Female
Reduced mobility and activity
Low BMI (<18.5 kg/m2)
Rheumatoid arthritis
Alcohol and smoking
Long term corticosteroids. NICE suggest the risk increases significantly with the equivalent of more than 7.5mg of prednisolone per day for more than 3 months)
Other medications such as SSRIs, PPIs, anti-epileptics and anti-oestrogens

post menopausal women- oestrogen is protective against osteoporosis so unless they are on HRT, they will have less oestrogen

Question 4

what is the FRAX tool

Answer 4

predicts the risk of a fragility fracture over the next 10 years

age, BMI, co-morbidities, smoking, alcohol, family history, bone mineral density (from DEXA)

gives a % risk of major osteoporotic fracture of hip fracture in next 10 years

Question 5

bone mineral density

Answer 5

measured using DEXA scan
dual - energy X-ray absorptiometry

measures how much radiation is absorbed in the bones which indicates the density

bone density can be represented as Z score or T score.

cores represent the number of standard deviations the patients bone density falls below the mean for their age. T scores represent the number of standard deviations below the mean for a healthy young adult their bone density is.

T score is most clinically important

Question 6

WHO classification of T score at the hip and bone mineral density

Answer 6

More than -1
Normal

-1 to -2.5
Osteopenia

Less than -2.5
Osteoporosis

Less than -2.5 plus a fracture
Severe Osteoporosis

Question 7

how to assess for osteoperosis

Answer 7

1. FRAX assessment in women >65, men >75, young patients with risk factors

FRAX outcome without a BMD result will suggest one of three outcomes:

Low risk – reassure
Intermediate risk – offer DEXA scan and recalculate the risk with the results
High risk – offer treatment

FRAX outcome with a BMD result will suggest one of two outcomes:

Treat
Lifestyle advice and reassure

Question 8

how to manage osteoperosis

Answer 8

conservative:
activity + rest
maintain healthy weight
adequate ca2+ intake
adequate vitamin D intake
avoid falls
stop smoking
reduce alcohol

medical:
vitamin D and calcium
calcichew D3 (contains 1000mg of calcium and 800 units of vitamin D cholecalciferol)

bisphosphonate
interfere with osteoclast which prevent resorption of bone
alendronate 70mg weekly
risedronate 35mg weekly
zoledronic acid 5mg once yearly IV

Question 9

what are some side effects of bisphosphonate?

Answer 9

reflux and oesophageal erosions
important to take on empty stomach and sit upright for 30 minutes before moving or eating to prevent reflux

atypical fractures
osteonecrosis of the jaw and external auditory canal

Question 10

other medical options for osteoporosis (if bisphosphante is contraindicated)

Answer 10

Denosumab is a monoclonal antibody that works by blocking the activity of osteoclasts.

Strontium ranelate is a similar element to calcium that stimulates osteoblasts and blocks osteoclasts but increases the risk of DVT, PE and myocardial infarction.

Raloxifene is used as secondary prevention only. It is a selective oestrogen receptor modulator that stimulates oestrogen receptors on bone but blocks them in the breasts and uterus.

Hormone replacement therapy should be considered in women that go through menopause early.

Question 11

what is the follow up regime for osteoporosis?

Answer 11

low-risk= do no treat, give lifestyle and follow up in 5 years (repeat assessment)

if on bisphosphonate = repeat FRAX and DEXA after 3-5 years

recommend treatment holiday
break from tx for 18 months - 3 years

Question 12

what is osteomalacia?

Answer 12

a condition where there is deceptive bone mineralisation which causes soft bones due to insufficient vitamin D

(osteo=bone malacia=soft)

Question 13

symptoms of osteomalacia

Answer 13

weak bones
bone pain
muscle weakness
fractures

Question 14

rickets

Answer 14

osteomalacia in children before their growth plates close

Question 15

what its the pathophysiology of osteomalacia

vitamin D synthesis

Answer 15

vitamin D is a hormone created from cholesterol in the skin in response to UV radiation

standard diet has inadequate levels of vitamin D to compensate for the lack of sun exposure.

deficiency

• reduced skin exposure
• insufficient intake of vitamin D
• malabsorption (IBD)
• CKD (kidneys are essential in metabolising vitamin D into it’s active form)

Question 16

importance of vitamin D

Answer 16

essential in absorption of ca2+ and phosphate from the kidneys and intestines. vitamin D is also responsible for bone turn over and promoting bone reabsorption to boost serum calcium level

inadequate vit D= inadequate ca2+ and phosphate in the blood = defective bone mineralisation

Question 17

how does osteomalacia present

Answer 17

Patients with vitamin D deficiency and osteomalacia may not have any symptoms. Potential symptoms are:

Fatigue
Bone pain
Muscle weakness
Muscle aches
Pathological or abnormal fractures 
looser zones (fragility fractures that go partially though the bone)

Question 18

how do we investigate for osteomalacia / low vitamin D

Answer 18

blood serum 25 hydroxyvitamin D
<25 nmol/L – vitamin D deficiency
25 – 50 nmol/L – vitamin D insufficiency
75 nmol/L or above is optimal

serum ca2+ (low)
serum phosphate (low)
serum ALP (high)
parathyroid (high, 2’)

imaging:
X-ray shows osteopenia (radiolucent bones)
DEXA (low bone mineral density)

Question 19

how to treat osteomalacia

Answer 19

conservative

medical:
vitamin D supplementation (cholecalciferol)

50,000 IU once weekly for 6 weeks
20,000 IU twice weekly for 7 weeks
4000 IU daily for 10 weeks

A maintenance supplementary dose for of 800 IU or more per day should be continued for life after the initial treatment.

Question 20

Paget’s disease of the bone

Answer 20

disorder of bone turnover
excessive bone turnover (formation and reabsorption) due to excessive activity of osteoblast and osteoclast

in-cordinated turnover which leads to patchy areas of high density (sclerosis) and low density (lysis)

enlarged + misshapen bones with structural problems which increases the risk of pathological fractures and typically affects the axial skeleton (head and spine)

Question 21

how does Paget’s present?

Answer 21

Bone pain
Bone deformity
Fractures
Hearing loss can occur if it affects the bones of the ear

*older adults

Question 22

investigation for Paget’s

Answer 22

bloods:
raised ALP
LFT normal
ca2+ normal
PO4- normal

imaging:
xray findings
Bone enlargement and deformity
“Osteoporosis circumscripta” describes well defined osteolytic lesions that appear less dense compared with normal bone
“Cotton wool appearance” of the skull describes poorly defined patchy areas of increased density (sclerosis) and decreased density (lysis)
“V-shaped defects” in the long bones are V shaped osteolytic bone lesions within the healthy bone

Question 23

how to manage Paget’s?

Answer 23

conservative

medical

• bisphosphonates. interfere with osteoclast activity to restore normal metabolism
• NSAIDs for bone pain
• Ca2+ and vit D

surgery:
for fractures, severe deformity and arthritis

monitor:
check serum ALP and review symptoms

Question 24

what are some complications of Paget’s?

Answer 24

osteogenic sarcoma (osteosarcoma)
bone cancer with poor prognosis. increased focal bone pain, bone swelling, pathological fractures. follow up

spinal stenosis (spinal cord compression). deformity of the spine leads to spinal canal narrowing. can press on spinal nerves- neurological signs and symptoms. MRI and treat with bisphosphonate. consider surgery.