Osteoporosis ☺️

Question 1

Etiologies and pathophysiology

-changes in bone mass with age

Answer 1

Systemic skeletal disease - low bone mass, abnormal architecture => reduced strength and increased risk of fracture

Imbalance between bone forming and breakdown

Both sexes start with similar bone mass but men constantly have more later in life
Both sexes lose bone mass
Due to menopause, women lose more
Peak bone mass in 30s

Question 2

Risk factors

• non modifiable
• modifiable
• comorbidities

Answer 2

Non modifiable
White, Asian
Female - post menopause, consistently less bone mass than men
Past #, FHx of hip #

Modifiable
Underweight BMI
14 unit+ alcohol
Smoking
GC use
VitaminD, Ca

Comorbidities
Diabetes - neuropathy and retinopathy, reduced anabolic impact of insulin
RA - inflammation, steroids
Chronic liver disease - malnutrition, low BMI, cholestasis
Chronic kidney disease - dialysis, ESRD
GI diseases - inflammation, malabsorption, surgery, steroids

Bone metastasis, cancers

Question 3

Signs and symptoms

Answer 3

Minimal trauma/from standing height - fragility fracture that could be related to bone mass
Low BMI
Spinal kyphosis from asymptomatic fracture
Low Ca, VitD intake

Question 4

When would you assess fracture of risk

Answer 4

All women 65+, men 75+

Women 50-64, men 50-74 if risk factors present

• past fragility fracture, Hx of falls
• frequent use of GC
• 2ndary osteoporosis
• low BMI
• smoking

Question 5

Routine bone investigations and why

Answer 5

FBC, CRP - signs of myeloma, lymphoma
U&E, LFTs - CKD, CLD
TFT, PTH - hyperthyroidism, PTH
VitD - deficiency
Urine cortisol/dexmeth suppression- Cushings 
Urine and serum - myeloma
Coeliac screen - malabsorption

Bone profile

• Ca
• PO4
• ALP- increased in bone formation
• albumin - needed to correct for Ca (some is bound to albumin, some is free)

FRAX - 10 year fracture risk
DEXA - T score compared to healthy individual
-osteopenia -1-2.5
-osteoporosis -2.5+

Question 6

What are the possible differentials

Answer 6

Iatrogenic/idiopathic

• Osteomalacia (VitD deficient => decreased minerals increased matrix) - similar presentation => PTH high
• steroid, immunomodulant use

Malignancy

• myeloma - bone pain, anemia, renal failure => urine, serum electrophoresis
• metastatic bone malignancy - bone pain => normal DEXA, tumour seen on CT
• breast, prostate cancer treatment

Degenerative
-CKD - bone pain, renal failure => high creatinine, PTH

Endocrine
-1ary hyperPTH => asymptomatic, signs of hypercalcemia => high PTH

Question 7

Management - conservative

Answer 7

Diet
-Ca, VitD3 supplements

Exercise
-regular weight bearing exercise

Question 8

Management - pharmacological

-SE

Answer 8

1st line - Bisphosphonates

• PO taken in the morning on an empty stomach with water, 30mins before food (alendronate, risendronate)
• SE - MRONJ, reflux, atypical fracture, dysphagia

Denosumab - inhibits osteoclast activation
-SE - infection, MRONJ, atypical fractures

Teriparatide

• intermittent bone formation from anabolic action of PTH
• when stopped, to prevent rapid bone loss => antiresorptive agent

Question 9

Management - pharmacological if others not tolerated

Answer 9

HRT - younger postmenopausal women
-O or OP

selective estrogen receptor modulator
-raloxifene

Question 10

What are the complications of

• osteoporosis
• management

Answer 10

Fractures

Medication

• bisphosphonates - atypical fractures due to excess mineralisation, MRONJ
• raloxifene - DVT, PE due to O

Question 11

Bone resorption markers

Bone formation markers

Answer 11

Urine and blood serum(products of breakdown)

• hydroxyproline
• C telopeptide type 1 collagen
• N telopeptide type 1 collagen

Not routinely done

Blood

• bone specific ALP
• osteocalcin
• P1CP
• P1NP

Question 12

Risk stratifying osteoporotic patients

Answer 12

Low risk - lifestyle changes, VitD Ca, watch and wait
-FRAX U10%

High - antiresorption 1st then bone forming

• PO alendronate
• FRAX 10-20%

V high - bone forming first

• IV zolendronate/teriparatide
• RRAX 20%+