Metabolic Bone Disease

Question 1

What is Paget’s disease

Answer 1

Disorder of bone turnover

There is increased bone resorption followed by increased bone formation leading to disorganised bone

Question 2

What is bone like in Paget’s (4)

Answer 2

Bigger
Less compact
More vascular
More susceptible to deformity and fracture

Question 3

What percentage of Paget’ is familial - what is the gene involved

Answer 3

15-30%
Loci of SQSTMI
Anglo-Saxon origins

Question 4

Presentation of Paget’s (5)

Answer 4

Bone pain - blood gives deep pulsating pain
Bone deformity
Excessive heat over Pagetic bone
Neurological complications - i.e. nerve deafness
Development of osteosarcoma in affected bone (rare)

Question 5

What age group does Paget’s occur in

Answer 5

Over 40s

Question 6

What scan is used for Paget’s - what does it show

Answer 6

Isotope bone scan shows area of dense bone

Question 7

What bone and liver enzyme is affected by Paget’s and how

Answer 7

Serum alkaline phosphatase is elevated

Question 8

differential of Paget’s

Answer 8

metastatic cancer

Question 9

When is treatment for Paget’s indicated

Answer 9

If in skull or area requiring surgical intervention - do not treat based on a raised AlkPhos alone

Question 10

What medication is used for Paget’s

Answer 10

IV bisphosphonate

Question 11

what is a type of bisphosphonate used for Pagets

Answer 11

Zoledronate injection (one off)

Question 12

What is the difference between rickets and osteomalacia

Answer 12

Ricket’s is before the epiphyseal plates have fused

Osteomalacia is after the epiphyseal plates have fused

Question 13

Clinical presentation of rickets (4)

Answer 13

Stunted growth
Bandy legs (wide)
Large skull (fontanelles do not fuse)
Failure to thrive

Question 14

Clinical presentation of osteomalacia (5)

Answer 14

No visible deformity 
Microfractures 
Bone pain 
Muscle weakness
Increased fall risk

Question 15

Who is most at risk of osteomalacia

Answer 15

Institutionalised

Question 16

what causes rickets or osteomalacia

Answer 16

Severe nutritional vitamin D or calcium deficiency causes insufficient mineralisation.
Vit D stimulates calcium and phosphate absorption from the gut which then becomes available for bone mineralisation.
So less vit D means less Calcium and phosphate so less bone mineralisation

Question 17

Apart from reduced bone mineralisation, what else in the body is affected by low vitamin D states

Answer 17

Muscle function

Question 18

What is osteogenesis imperfecta

Answer 18

Genetic disorder of connective tissue characterised by fragile bones from mild trauma and even acts of daily life

Question 19

Who does OI affect

Answer 19

Broad range from prenatally fatal to those presenting in 40s with “early osteoporosis

Question 20

Where is the defect which causes OI

Answer 20

Defects in type I collagen

Question 21

What are the 4 most common types of OI

Answer 21

T1 - milder form, occurs when child starts to walk, can present in adults

T2 - lethal by age 1

T3 - progressive deforming with severe bone dysplasia and poor growth

T4 - similar to T1 but more severe

Question 22

Other clinical features of OI (7)

Answer 22

Growth deficiency
Defective tooth formation (dentinogenesis imperfecta)
Hearing loss
Blue sclera
Scoliosis / Barrel chest
Ligamentous laxity (hyper mobility brighten score)
Easy bruising

Question 23

Management of OI (4)

Answer 23

Surgery to treat fractures
IV Bisphosphonates (to prevent fracture)
Educational and social adaptations
Genetic counselling for parents and next generation

Question 24

What is osteoporosis

Answer 24

A metabolic bone disease characterised by low bone mass and deterioration of bone tissue resulting in bone fragility and increased fracture risk

Question 25

What tools are used to assess fracture risks (2) - what do they assess and what are the difference between these tools

Answer 25

Both assess 10 year probability of bone fracture risk FRAX - uses clinical risk factors and BMD at the femoral neck Q Fracture - does not have ability to add BMD

Question 26

If a patient has significant risk of fracture result from FRAX/Q Fracture, what should they be referred for

Answer 26

DEXA scan | risk >10%

Question 27

Who should be referred for a DEXA scan for osteoporosis regardless of their fracture risk percentage

Answer 27

If on oral steroids | If suffered a low trauma fracture

Question 28

What does DEXA scan measure

Answer 28

Bone mineral density which is then compared to the BMD of a healthy adult and someone who is same age and sex as patient. The difference is calculated as a SD and called a T score

Question 29

What T score is defined as osteoporosis

Answer 29

Below -2.5 SD

Question 30

What bones are good to scan in DEXA and why

Answer 30

L1-L4 as spine has more cortical bone than trabecular bone so commonly affected by osteoporosis L1-4 also doesn't have other bones around it to interfere with the scan

Question 31

Endocrine causes of osteoporosis (6)

Answer 31

``` Thyrotoxicosis Hyper and Hypoparathyroidism Cushing's Hyperprolactinaemia Hypopituitarism Low sex hormone levels ```

Question 32

Rheumatic causes of osteoporosis (3)

Answer 32

RA Ankylosing Spondylitis Polymyalgia Rheumatica (steroids used making bones thin)

Question 33

GI causes of osteoporosis (11)

Answer 33

``` IBD Primary biliary cirrhosis Alcoholic cirrhosis Congenital adrenal hyperplasia Viral cirrhosis (hep C) Cystic Fibrosis (causes malabsorption) Chronic pancreatitis Coeliac disease Whipple's disease Short gut syndromes Ischaemic bowel ```

Question 34

Medications which cause osteoporosis

Answer 34

``` Steroids PPI Enzyme inducing anti-epileptic medications Aromatase inhibitors GnRH agonists Warfarin ```

Question 35

Non pharmacological ways to prevent osteoporosis

Answer 35

Minimise risk factors Ensure good calcium and Vitamin D status Falls prevention strategies

Question 36

Medications to treat osteoporosis (5)

Answer 36

Oral bisphosphonates (main) HRT Selective Oestrogen Receptor Modulator-Raloxifene (SERMS) Denosumab s/c injection (6m) Teriparatide (human parathyroid hormone) injection

Question 37

What needs to be checked for bisphosphonates

Answer 37

Renal function Calcium and Vit D status Good dental health and hygiene - notify dentist

Question 38

Side effects of bisphosphonates (4)

Answer 38

Osteonecrosis of Jaw Oesophagitis Iritis / uveitis Atypical femoral shaft fractures

Question 39

Side effects of HRT

Answer 39

Blood clots risk Breast cancer risk increased Heart disease and stroke risk increased if used after large gap from menopause

Question 40

Side effects of SERMS

Answer 40

Hot flushes Increased clotting risks Leg cramps

Question 41

What is denosumab and how does it help in osteoporosis

Answer 41

Monoclonal antibody against RANKL Reduces osteoclastic bone resorption Safer in patients with significant renal impairment

Question 42

Side effects of denosumab

Answer 42

Allergy / rash Symptomatic hypocalcaemia if given when via D depleted ONJ Atypical femoral shaft #

Question 43

Teriparatide side effects

Answer 43

injection site irritation Hypercalcaemia (rare) allergy COST