Biochem disorders of bone

Question 1

Give examples of bisphosphonates

Answer 1

Alendronate
Risedronate
Etidronate

Question 2

What is desunomab

Answer 2

Monoclonal antibody which reduces osteoclastic activity

Question 3

What does strontium do?

Answer 3

Increases osteoblast replication and reduces resorption

Question 4

What is Zoledronic acid?

Answer 4

Once yearly IV bisphosphpnate (but v expensive)

Question 5

Risks of HRT

Answer 5

Inreased breast and endometrial cancer rates

DVT

Question 6

Risks of Raloxifene (oestrogen receptor modulator)

Answer 6

DVT

Question 7

Qualitive defect of bone

Answer 7

Osteomalacia

• due to deficient mineralisation of osteoid
• INADEQUATE AMOUNTS OF CALCIUM AND PHOSPHATE

Question 8

Psuedofractures (Looser’s zones)

Answer 8

Osteomalacia

Question 9

Patients may complain of bone pain, have deformities of soft bones, sustain pathological fractures easily and have symptoms of hypocalcemia

Answer 9

Osteomalacia

Question 10

Low calcium
Low phosphate
High serum alk phos

Answer 10

Osteomalacia

Question 11

Blood biochem in osteoporosis

Answer 11

Normal

Question 12

Brown tumours

Answer 12

Caused by hyperparathyroidism (lytic lesions in bone)

Question 13

Osteitis fibrosa cystica

Answer 13

Caused by hyperparathyroidism

Question 14

Treatment for high serum calcium

Answer 14

EMERGENCY
IV fluids
Bisphosphonates
Calcitonin

Question 15

Treatment of hyperparathyroidism

Answer 15

Removal of adenomatous glands
Treatment of underlying cause (vitamin D supplementation)
Emergency treatment for very high calcium

Question 16

What is renal osteodystrophy

Answer 16

Typical bone changes due to CKD
(reduced phosphate excretion and inactive activation of vitamin D –> sclerosis of bones and calcification of soft tissues)

Question 17

Type 1 osteoporosis

Answer 17

Post menopausal

Colles fracture and vertebral insufficiency fracture most likely

Question 18

Type 2 osteoporosis

Answer 18

Osteoporosis of old age

Fracture of vertebra and femoral neck most common

Question 19

Causes of hypophosphatemia

Answer 19

Refeeding syndrome

Alcohol excess

Question 20

Principal cause of osteomalacia

Answer 20

Insufficienct calcium from the intestine because of lack of dietary calcium or a deficiency of or resistance to the action of vitamin D, or phosphate deficiency caused by increased renal losses

Question 21

Drugs associated with poor bone quality

Answer 21

Long term anticonvulsant use

Question 22

Treatment for pagets

Answer 22

Bisphosphonates (inhibit osteoclasts) or calcitonin if extensive lytic disease

Question 23

Defect of which type of collagen in osteogenesis imperfecta?

Answer 23

Type 1

Question 24

Osteogenesis imperfecta method of inheritence

Answer 24

Autosomal dominant

Question 25

Blue sclera and loss of hearing

Answer 25

Osteogenesis imperfecta

Question 26

Sofield procedure

Answer 26

Multiple osteotomies and intramedullary stabilisation for progressive deformity caused by OSTEOGENESIS IMPERFECTA

Question 27

Prominent forehead widened nose Lax joints Normal mental development

Answer 27

Achondroplasia

Question 28

Marfan inheritence

Answer 28

Autosomal dominant

Question 29

Tall stature, disproportionately long limbs and ligamentous laxity High arched paalte Scoliosis Pectus excavatum Eye problems (lens dislocation, retinal detachment) Aortic aneurysm Cardiac valve incompetence

Answer 29

Marfan syndrome

Question 30

Which dislocation common in Down syndrome?

Answer 30

Patella | Atlanto-axial instability in the C-spine

Question 31

Profound joint hypermobility, vascular fragility with ease of bruising, joint instability and scoliosis

Answer 31

``` Ehlers Danlos (autosomal dominant) ```

Question 32

Diagnosis is by raised serum creatinine phosphokinase and abnormalities on muscle biopsy

Answer 32

Duchenne muscular dystrophy

Question 33

Hypoplastic bones

Answer 33

Short

Question 34

If you have limb malformations caused in gestation, when would they have occurred?

Answer 34

between 4th and 6th week of gestation

Question 35

What is syndactyly?

Answer 35

COMMONEST congenital malformation -two digits are fused (usually separated age 3/4)

Question 36

Polydactyly

Answer 36

Extra digit

Question 37

Fibular hemimelia

Answer 37

Absence of fibula - leads to shortened limb - bowing of tibia - ankle deformity

Question 38

Most common congenital fusion

Answer 38

Tarsal coalition

Question 39

Erbs palsy

Answer 39

Damage to C5 and C6 during pregnancy | loss of motor innervation of the deltoid, supraspinatus, infraspinatus, biceps and brachialis

Question 40

What does erbs palsy look like

Answer 40

Humerus is internally rotated (unopposed subscapularis) "waiter's tip posture" Physiotherapy Prognosis good

Question 41

What is Klumpe's palsy?

Answer 41

Lower brachial plexus palsy (C8 and T1) Paralysis of intrinsic hand muscles +/- wrist flexors an POSSIBLE horner's syndrome Fingers typically flexed (hand looks a bit like spider man but not quite) No specific treatment Prognosis poor

Question 42

Babinski sign

Answer 42

UMN

Question 43

Drugs which can help reduce spacticity

Answer 43

Baclofen | Botox

Question 44

Meningocele

Answer 44

This is in spina bifida | --> menignocele not usually associated with neurological sequelae

Question 45

Myelomeningocele

Answer 45

Usually has neurological deficit

Question 46

Spina bifida and the feet

Answer 46

Can cause high arched foot!!!

Question 47

A viral infection affecting motor anterior horn cells in the spinal cord or brainstem resulting in a lower motor neurone deficit

Answer 47

Polio