Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

MD2 Musculoskeletal > Metabolic Bone Disease > Flashcards

Metabolic Bone Disease Flashcards

1
Q

Mrs Roberts, a 65 year old postmenopausal woman, develops acute severe back pain while picking up her 4 year old grandchild

No PHx of back pain

Current height 168cm, but was 173cm tall when married 42 years previously

Weight is 72kg and BMI 25.5

Caucasian

DDx?

A

Acute onset of severe back pain: acute disc disruption +/- nerve root compression, acute vertebral fracture, or pathological cause (e.g. bony mets, multiple myeloma)

Height loss: likely due to loss of height of vertebra(e) or intervertebral disc spaces (≥3cm of height loss is significant)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

List 10 RFs for OP

A

Low exercise levels

Smoking

Co-morbidities (e.g. RA)

Poor nutrition (low Ca2+ intake)

Risk of vit D insufficiency (e.g. no sun exposure, poor diet)

Prolonged amenorrhoea in younger years

Early menopause

PHx of #

FHx of #/OP

Lack of previous/current therapies for postmenopausal OP

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Mrs Roberts, a 65 year old postmenopausal woman, develops acute severe back pain while picking up her 4 year old grandchild

PHx: T2DM complicated by microalbuminaemia and mild peripheral neuropathy

Rx: mixed insulin

Widowed, lives alone, doesn’t like to cook

O/E: well-looking, slightly overweight, no Cushingoid features, afebrile, RR 14, HR 80 regular, BP 135/90, signs of hyperinflation with some scattered wheeze, moderate kyphosis with tenderness over mid-thoracic spine, normal breast examination

Most likely Dx? Ix?

A

Osteoporotic crush #

Ix: XR thoracolumbar spine to confirm

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Mrs Roberts, a 65 year old postmenopausal woman, develops acute severe back pain while picking up her 4 year old grandchild

An XR thoracolumbar spine was performed

Interpret the plain film

A

Anterior wedge compression #

Full series showed 30% anterior wedge compression # at T8 and 20% anterior wedge compression # at L2

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Describe the WHO criteria for Dx of OP

A

Normal: T-score ≥ -1 (reference standard for “normal” BMD is healthy 30 year old woman)

Osteopaenia: -1 to -2.4

OP: ≤ -2.5

Severe OP: ≤ -2.5 and ≥1 #

NB For every 1 SD decreased from normal, RR of # increases 1.5-2.5 fold

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Distinguish between the Z- and T-score of a DXA

A

Z-score: number of SDs above or below the mean for the patient’s age, sex and ethnicity

T-score: number of SDs above or below the mean of a healthy 30 year old adult of the same sex and ethnicity as the patient

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What does the DXA measure?

A

Area density in g/cm^2

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What does a Z-score less than -2 indicate?

A

May be useful in identifying those with underlying accelerated causes of bone loss

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

How is OP usually diagnosed?

A

Presence of fragility or minimal trauma #

BMD of spine and proximal femur by DXA

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Mrs Roberts, a 65 year old postmenopausal woman, develops acute severe back pain while picking up her 4 year old grandchild

Ix: FBG elevated (consistent with T2DM), HbA1c 7.3% (above goal of 7%), UEC indicates some renal insufficiency with eGFR of 40mL/min, LFTs reveal ALP of 140IU/L, 25-OH vit D 25nmol/L, PTH 14pmol/L, CMP normal, TSH normal, CRP normal

BMD T-score for lumbar spine is -2.35 and femoral neck is -2.98

How are bone resorption and formation measured?

A

Resorption: serum B-CTX (C-terminal telopeptide)

Formation: P1NP (N-terminal propeptide of type 1 procollagen)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Mrs Roberts, a 65 year old postmenopausal woman, develops acute severe back pain while picking up her 4 year old grandchild

Ix: FBG elevated (consistent with T2DM), HbA1c 7.3% (above goal of 7%), UEC indicates some renal insufficiency with Cr of 0.190mmol/L and eGFR of 40mL/min, LFTs reveal ALP of 140IU/L, 25-OH vit D 25nmol/L, PTH 14pmol/L, CMP normal, TSH normal, CRP normal

DXA: T-score for lumbar spine is -2.35 and femoral neck is -2.98

Bone turnover markers: serum B-CTX 0.52ng/mL, P1NP 108ug/L

What are the normal parameters for all these Ix?

A

FBG: 3.0-5.4mmol/L

Cr: 0.05-0.10mmol/L

eGFR: 40mL/min

GGT: less than 35IU/L

ALP: 30-120IU/L

25-OH vit D: optimal target is >50nmol/L

PTH: 1.2-6.5pmol/L

Ca2+ (corrected): 2.1-2.6mmol/L

Phosphate: 0.87-1.45mmol/L

TSH: 0.5-5mIU/L

CRP: <10mg/L

T-score: ≥1

B-CTX: >30 years premenopausal women should be less than 0.45ng/mL

P1NP: premenopausal women should be less than 70ug/L

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What is P1NP?

A

Marker of bone formation

Procollagen type 1 propeptides

Cleared by liver endothelial cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What is CTX? Briefly describe its pharmacokinetics

A

Marker of bone resorption (cleaved during bone resorption)

Diurnal variation (peak at 8-9.30am)

Must be measured fasting

Cleared by kidneys

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

List 5 common secondary causes of OP which are correctable

A

Cushing’s syndrome or use of exogeous corticosteroids (>5mg/day for >3/12)

Excessive alcohol use (>2 units or 18g/day)

Smoking

Malabsorption (e.g. coeliac disease, IBD)

Primary or secondary hypogonadism (including Rx-associated, e.g. corticosteroids, opioids, androgen deprivation therapy for prostate Ca, aromatase therapy for breast Ca)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

List 13 less common secondary causes of OP

A

Low BMI (below 20) and associated eating disorders

Lack of or excessive exercise

Thyrotoxicosis or thyroxine over-replacement

Primary hyperPTH

Chronic liver or kidney disease

Hypercalciuria

RA or ankylosing spondylitis

DM

MM

HIV or its treatment with protease inhibitors

Mastocytosis

Organ transplant or immunosuppressive (e.g. cyclosporin/cyclophosphamide, tacrolimus)

Osteogenesis imperfecta

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Give 2 examples of tools developed to calculate # risk in patients with OP

A

FRAX (WHO # Risk Assessment Tool)

Garvan Tool

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

What factors must be taken into account when deciding on appropriate treatment for OP?

A

Patient/family’s wishes

Benefit/risk ratio for each treatment

Severity of disease

Prior treatment

Presence of co-morbidities that might influence choice of medication (e.g. dysphagia, achalasia)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What are the goals of OP Mx?

A

risk reduction

Reduction in mortality through hip # avoidance

Improve QoL with preserved mobility and independence

19
Q

List 6 therapies available for OP

A

HRT (mostly women only)

Raloxifene (women only)

Bisphosphonates: alendronate, risedronate, zoledronate

Teriparatide

Denosumab

Strontium

20
Q

Outline the mechanism of HRT and SERMs as treatment for OP

A
21
Q

Outline the mechanism of bisphosphonates as treatment for OP

A
22
Q

Outline the mechanism of denosumab as treatment for OP

A
23
Q

Outline the mechanism of teriparatide as treatment for OP

A
24
Q

Outline the mechanism of strontium as treatment for OP

A
25
Q

SEs of bisphosphonates

A

GIT

ONJ

Atypical #

Progression of stage 4 CKD

26
Q

SEs of denosumab

A

ONJ

Atypical #

Hypocalcaemia

Infection

Allergy

27
Q

SEs of raloxifene

A

GIT

Thrombosis

Progression of stage 4 CKD

28
Q

Teriparatide SEs

A

Hypercalcaemia

?osteosarcoma (rodent studies)

Progression of stage 4 CKD

29
Q

What is the relationship between strontium and CVD? What are the clinical implications of this?

A

Pooled data from RCT studies showed that women using strontium ranelate were at increased risk of MI compared with placebo; however, mortality was not increased

Strontium is contraindicated in patients with a Hx of IHD, PVD or CVD, and patients with HTN with SBP ≥160mmHg or DBP ≥90mmHg

Relative contraindications include patients with significant RFs for CV events (e.g. HTN, hyperlipidaemia, DM, smoking)

30
Q

What criteria must be met for patients to qualify for PBS reimbursement for teriparatide?

A

Severe OP

T score less than -3.0

2 minimal trauma #s

One fracture occurring despite at least 12/12 of anti-resorptive drug treatment

OR intolerance to oral and IV bisphosphonates

I.e. must have had a trial of anti-resorptive treatment, including bisphosphonates

31
Q

List 5 contributing factors to #s in CKD

A

OP

Osteomalacia

HyperPTH

Adynamic bone disease

Post-transplantation (steroid, calcineurin inhibitors)

32
Q

Describe the mechanism of hyperPTH in CKD. What are some other causes of secondary hyperPTH?

A

Failing kidneys do not convert enough vitamin D to its active form, and they do not adequately excrete phosphate. When this happens, insoluble calcium phosphate forms in the body and removes calcium from the circulation. Both processes lead to hypocalcemia and hence secondary hyperparathyroidism.

Secondary hyperparathyroidism can also result from malabsorption (chronic pancreatitis, small bowel disease, malabsorption-dependent bariatric surgery) in that the fat-soluble vitamin D can not get reabsorbed.

33
Q

What is adynamic bone disease? Are there any important considerations for ABD as a cause of OP?

A

Adynamic bone disease (ABD) is a variety of renal osteodystrophy characterized by reduced osteblasts and osteoclasts, no accumulation of osteoid and markedly low bone turnover

Seen in CKD, esp in dialysis patients

Note that in ABD, anti-resorptive therapy increases #

34
Q

How should the dose of bisphosphonates be altered in CKD patients? Give an example of a drug regimen that may be recommended

A

Bisphosphonates are renally excreted and although there is no therapeutic drug monitoring (consider monitoring with ALP?), dose reduction by 50% may be indicated

Risedronate 35mg fortnightly to monthly

35
Q

Describe the current recommendations for OP Mx in CKD patients

A

1-3a: same as patients without CKD

3b: caution with IV bisphosphonates, dose reduction with oral bisphosphonates
4: and 4d: bisphosphonates with hypocalcaemia precaution
5: no data

36
Q

What renal AEs have been seen in case reports with IV bisphosphonates?

A

Glomerulosclerosis or ATN

37
Q

What is the most probable cause of # in patients with stage 1-3 CKD? How should these patients be managed?

A

OP, rather than CKD-MBD once other metabolic/biochemical abnormalities are corrected (e.g. hyperphosphataemia, secondary hyperPTH)

Consider treatment with antiresorptives once secondary causes of OP are excluded, and ensure adequate Ca2+ and vit D (particularly is deficiency is present)

38
Q

What are the 4 main options for OP Mx in patients with CKD?

A

Raloxifene: vertebral # risk protection only

Oral alendronate: weekly tablet

Oral risedronate: weekly or monthly tablet

6/12ly SC denosumab injections

39
Q

What are the 3 stages of ONJ?

A

1) Asymptomatic
2) Pain + inflammation/infection
3) Pain + inflammation/infection + osteolysis

40
Q

What is ONJ?

A

Exposed necrotic bone >8 weeks

41
Q

List 6 RFs for ONJ

A

IV bisphosphonates (malignancy) 0.8-12%

Prolonged bisphosphonates

Steroids

Smoker

Poor oral hygiene

Also reported in denosumab

42
Q

What is the rate of ONJ for patients on oral bisphosphonates?

A

1 in 100,000 patient years

Oral bisphosphonates calculated ONJ rate was 0.01-0.04%, which increased to 0.09-0.34% if extraction performed

43
Q

What is one of the limitations of bisphosphonates, illustrated in the attached radiograph?

A

Plain film shows an incomplete atypical femoral # (lateral break, suggestive of stress #) with periosteal thickening

Risk of atypical # (including atypical femoral #) increases with prolonged bisphosphonate use and decreases rapidly with cessation

BUT uncommon

44
Q

When should a “drug holiday” in OP be considered?

A

If BMD increased to >T = -.25 at femoral neck after 3-5 years (but drug holiday can only be considered if patient is monitored for any subsequent bone loss)

MD2 Musculoskeletal (12 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions