Infection of locomotor tissue + bone disease Flashcards

1
Q

mortality rate septic arthritis

A

10%

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2
Q

Where does septic arthritis common originate

A

Skin/resp tract

then haematogenous spread

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3
Q

RF septic arthritis (5)

A
Extremes of age 
Pre-existing joint disease 
IVDU
DM/immunosupp
Recent op
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4
Q

Most common organism septic arthritis

A

Staph aureus

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5
Q

Most common organism septic arthritis - young adults

A

Disseminated gonococcal infection

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6
Q

Most common organism septic arthritis - child

A

Step pneumonia

H influenza

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7
Q

What is osteomyelitis

A

Infection of the bone

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8
Q

Where does osteomyelitis classically target children

A

Metaphyseal plates of long bones

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9
Q

Where does osteomyelitis classically target immunosuppressed adults?

A

Spine

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10
Q

PS bone/joint sepsis (4)

A

Monoarthritis
Hot, swollen, erythematous joint
Loose pack
Knee/hip commonly

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11
Q

O/E joint/bone sepsis (4)

A

Fever + systemic upset
Demonstrable effusion
Decr ROM
Extreme pain in passive movement

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12
Q

DDx septic arthritis

A

Crystal arthritis
Osteomyelitis
Reactive arthritis
Cellulitis

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13
Q

Ix septic arthritis (6)

A

Joint aspiration

Bloods - culture, FBC, ESR/CRP, uric acid, clotting

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14
Q

Mx septic arthritis (8)

A
A-E + Sepsis 6
Admit under ortho 
Aspirate joint 
2g IV fluclox 6hrly for 2-3 weeks followed by 6w PO 
Monitor ESR/CRP to guide Abx 
Pain relief 
Washout in theatre 
Early active rehab
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15
Q

Use of Xrays in acute septic arthritis?

A

No value in acute diagnosis

Maybe some soft tissue swelling @ fortnight

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16
Q

Xray findings post septic arthritis

A

Narrow joint space

B/c cartilage = destroyed

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17
Q

Pathology osteomyelitis

A

Inflamm –> Incr intraosseous P + pain
Supparation –> pus in medulla –> abscess/sinus
Necrosis
New bone formation

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18
Q

Mx osteomyelitis

A

ABx

+ Controlled interosseous P

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19
Q

When does viral arthropathy tend to occur?

A

During prodromal phase

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20
Q

Is viral arthropathy symmetrical or asymmetrical

A

Symmetrical

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21
Q

Ix viral arthropathy

A

viral titre/antigens

RF

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22
Q

Def Osteoporosis

A

Decr bone mineral density >2.5 SD below that of young adult male

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23
Q

What % of Post-menopausal women will suffer an osteoporotic fracture?

A

50%

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24
Q

T score osteopenia

A

-1 - -2.5

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25
Q

T score osteoporosis

A

< -2.5

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26
Q

RF Osteoporosis (7)

A
Age 
Female 
Genetics 
Low peak bone mass 
Disuse
Smoking 
CCS use
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27
Q

Secondary causes osteopororsis (8)

A
1' HyperPTH
Thyrotoxicosis 
Steroid induced 
Cushings 
Anorexia nervosa 
Malabsorpative conditions 
Chronic inflammatory disease 
Malignancy
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28
Q

PS OP (5)

A
Mostly asymp 
If Sx : 
Fragility fractures 
Back pain 
Height loss 
Kyphosis
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29
Q

Ix OP (8)

A

DEXA scan
Hx (predisposing cause)
Exam - endocrine + inflamm disease
Bloods: Se Ca, PO4, TFT, ESR,

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30
Q

What is a T score

A

How many SD below a young adult male

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31
Q

What is a Z score

A

How many SD below age-matched control

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32
Q

How to calculate probability of fragility fractures for OP patients

A

FRAX tool (for pt over 50)

33
Q

Low FRAX (<5.0)

A

Reassure

34
Q

Moderate FRAX (5-7.5)

A

DEXA

35
Q

High FRAX (>7.5)

A

DEXA + Tx

36
Q

Mx of pt w/ osteopenia

A

Lifestyle advice e.g. stop smoking/alcohol
Increase Ca + exercise
Repeat DEXA scans

37
Q

Medical Mx of established OP

A

Vit D + Ca
Weekly bisphosphonates
Denusomab S/C every 6 months
HRT if pre-mature menopause

38
Q

1st line weekly bisphosphonates - OP

A

Alendronic acid

39
Q

How does alendronic acid work

A

Decreases bone resportion

Allows mineralisation to increase

40
Q

If Alendronic acid is not tolerated, what bisphosphonate is 2nd line?

A

Risdronate

41
Q

What is Denusomab

A

Monoclonal AB that inhibits osteoclast activity

42
Q

SE Aldendronic acid

A

GI/Ulcer

Jaw necrosis

43
Q

What is Osteomalacia

A

Normal bone tissue but inadequate bone mineralisation

44
Q

Cause osteomalacia

A

Vit D deficiency

45
Q

What is Rickets

A

Syndrome resulting from osteomalacia in growing skeleton

46
Q

Deformities in Rickets (2)

A

Knock knee

Bow legs

47
Q

Why does low Vit D lead to loss of Ca and PO4 from bone

A

Norm: Vit D –> Incr Ca uptake from intestines + decr Ca excretion
If Low Ca - PTH secreted –> 2’ hyperPTH
Stims osteoclastic bone resportion, decr Ca excretion _ Incr PO4 excretion

48
Q

RF vit D deficiency (5)

A
Inadequate intake 
Inadequate synthesis (house bound) 
Renal disease 
Liver  disease 
Drugs
49
Q

PS Osteomalacia

A

Bone pain
Fragility + #
Insidious - malaise + weakness

50
Q

Ix Vit D deficiency/Osteomalacia (+results) (6)

A
U+E
ALP incr
Plasma Ca - low/norm
Se PO4 = low 
PTH = high 
Se Vit D = low
51
Q

XR features osteomalacia (3)

A

Norm
Or looser zones
Children - widening epiphyseal plate

52
Q

Mx osteomalacia

A

PO VIt D
High dose 4 w then maintenance
Activated vit D if hepatic/renal disease

53
Q

What is the difference between osteoporosis + osteomalacia

A

OP - decr bone mass w/ norm ratio mineral: matrix

OM - Mineral to matrix ratio = decreased

54
Q

Who gets Paget’s disease of hte bone

A

elderly

55
Q

Pathophysiology Paget’s disease of the bone

A

XS uncontrolled resportion of bone by large multinucleated osteoclasts
Destruction of cortical + trabecular bones in waves
Each wave = followed by osteoblastic response

56
Q

Bone changes Pagets

A

XS resorption + destruction –> defective bone architechture w/ incr bone bulk + weaker
New bone is woven, non-lamellar + fibrous

57
Q

What % of Pagets are asymp

A

80%

58
Q

Sx Pagets

A

Waxing + waning bone pain
Bone deformities
CN palsy
Cardiac failure

59
Q

Classic textbook PS Pagets

A

Bone pain
Patho #
Deafness

60
Q

Which CN is classically affected in Pagets?

A

CN VIII

61
Q

Which 2 bones are classically affected by deformites in Pagets

A

Tibia (bowing)

Skull

62
Q

Which other condition does Pagets greatly (x30) increase your risk of developing?

A

Osteogenic Sarcoma

63
Q

Ix Pagets (5)

A
Bloods
ALP - incr
Ca/PO4 norm
Urine: incr Hydroxyproline 
XR - lytic/sclerotic 
Bone Scan
64
Q

Tx Pagets (3)

A

Analgesia
Bisphosphonates
Monitor Se ALP

65
Q

When is surgery indicated in Paget’s Tx (2)

A

Joint disease

Neuro complications

66
Q

What is osteonecrosis

A

Ischaemic bone necrosis

Due to BM cells dying within 12hrs

67
Q

What is osteonecrosis called if in the shaft

A

Bone infarction

68
Q

What is osteonecrosis called in the epiphysis of the bone

A

Avascular necrosis

69
Q

Common causes osteonecrosis

A

Interupted blood supply - #

Interrupted vv drainage - thrombus/BM swelling

70
Q

RF osteonecrosis (6)

A
# e.g. NOF/Scaphoid 
Idiopathic - Perthe's, AVN femoral head 
BM infiltration - malignancy 
Alcohol 
Cushings/CCS
Infection - septic arthritis
71
Q

Target sites osteonecrosis (4)

A

Head of femur
Proximal scaphoid
Lunate
Body of talus

72
Q

PS Osteonecrosis (4)

A

Well advanced at PS
Pain
Stiffness
Swelling in joint

73
Q

Ix osteonecrosis (2)

A

XR - incr density

MRI/Radionucleotide scan

74
Q

How long does it take for osteonecrosis to show up on XR

A

6 months

75
Q

Mx Osteonecrosis (3)

A

ID + eliminate cause
Prevent complications - W relief + splinting
Surgery

76
Q

Osteopenia - Ca, PO4, ALP, PTH levels

A

Ca norm
PO4 norm
ALP norm
PTH norm

77
Q

Osteopetrosis - Ca, PO4, ALP, PTH levels

A

Ca norm
PO4 norm
ALP elevated
PTH norm

78
Q

Osteomalacia/Rickets - Ca, PO4, ALP, PTH

A

Ca decr
PO4 decr
ALP incr
PTH incr

79
Q

Paget’s disease of the bone - Ca, PO4, ALP, PTH

A

Ca norm
PO4 norm
ALP variable
PTH norm