Bone and Skin Flashcards
1
Q
2 types of formed bones?
A
Lamellar (organised well, strong)
Woven (haphazardly organised, weak)
2
Q
What is aseptic necrosis?
A
Death of bone due to interference with its blood supply
3
Q
What is Perthe’s disease?
A
aseptic necrosis of femoral epiphysis and head
4
Q
How does Perthe’s disease present?
A
In children, boys > girls
5-11yrs
pain and limp!!!
5
Q
What is osteomyelitis?
A
inflammation of the bone due to bacterial infection
6
Q
Who and where is osteomyelitis most common?
A
In children
in the metaphysis of long bones
7
Q
Causes of osteomyelitis?
A
Blood-borne
Compound fracture
direct spread from adjacent infection
8
Q
Causative organisms of osteomyelitis?
A
Coagulase and staph
salmonella (in sickle cell disease)
9
Q
Acute osteomyelitis symptoms?
A
high fever, severe pain, tenderness, WCC
10
Q
Treatment of acute osteomyelitis?
A
Prompt antibiotic treatment
11
Q
Complications of acute osteomyelitis?
A
sepsis, septic arthritis, chronic osteomyelitis, sinus tract formation, amyloidosis, SCC in sinus tract, abscess
12
Q
Septic arthritis causes?
A
Haematogenous spread
Direct spread
Following penetrating injury
13
Q
Septic arthritis causative organisms?
A
staph
strep
14
Q
Clinical presentation of septic arthritis?
A
red, hot, swollen joint
15
Q
Rheumatoid Arthritis associated HLA?
A
HLA-DR4
16
Q
What do 85% of RA patients have in their serum?
A
Rheumatoid factor
17
Q
Where does RA usually affect?
A
symmetrical proximal interphalangeal joints
18
Q
Extra-articular manifestations of RA?
A
Rheumatoid nodules Vasculitis Cardiac disease Pulmonary disease Amyloidosis Anaemia Uveitis, Scleritis
19
Q
What is sero-negative arthritis?
A
a group of diseases in which tests for rheumatoid factor are negative
20
Q
What joints are typically involved in sero-negative arthritis?
A
sacroiliac joints and spine
as well as typical peripheral joints
21
Q
What HLA is associated with with seronegative arthritis?
A
HLA-B27
22
Q
What is ankylosing spondylitis?
A
a polyarthritis which may eventually result in ‘Bamboo’ rigidity
inflammation -> fusion -> rigidity
23
Q
What HLA is associated with ankylosing spondylitis?
A
HLA B27 (90%)
24
Q
When does ankylosing spondylitis begin and how does it present?
A
Early 20s
pain and limitation of movements at sacroiliac joints
25
Extra-articular manifestations of ankylosing spondylitis?
aortic valve incompetence, uveitis, IBD, peripheral arthropathy
26
Where are changes seen in osteoarthritis?
in the articular cartilage and bone
| minimal change in synovium
27
Treatment of osteoarthritis?
Replace with artificial joint
28
Crystal arthropathies include?
gout (urate crystals)
pseudogout (calcium pyrophosphate crystals)
oxalate (in pts on dialysis)
29
Causes of gout?
idiopathic decrease in uric acid excretion
secondary to thiazide diuretics
secondary to chronic renal failure
inc. production due to inc. cell turnover
inc. purine synthesis
high dietary purine
30
Acute gout symptoms?
red, hot, tender, painful
big toe
ppt by alcohol, drugs, surgery
uric acid crystals in synovium and fluid
31
Chronic gout symptoms?
cartilage of ear & joints
crystalline deposits of urate in fibrous tissues and cartilage
deposits- tophi
foreign body type giant cell reaction
32
Factors that affect fracture healing?
```
movement
interposed soft tissue
gross misalignment
infection
pre-existing bone disease
```
33
Most common tumour in bone?
Secondary tumour- mets
34
Primary tumour of bone categories?
Benign
Borderline (locally aggressive/recurrent but doesn't mets)
Malignant
35
What is the commonest true primary bone tumour?
Osteosarcoma
36
What age do osteosarcomas occur in?
75% in 10-25yrs
| in patients >40yrs, 50% associated with Paget's disease
37
Most common sites for osteosarcoma?
lower femur, upper tibia/humerus
| pelvis in Paget's
38
Features of osteosarcoma?
medullary cavity
sunray spicules
+/- soft tissue extensions
39
Prognosis for osteosarcoma?
5yr survival = 50-60%
| mets via blood to lungs occurs early on
40
What is Ewing's tumour?
cavity of long bones, ribs and pelvis that begins in medullary cavity
41
Who does Ewing's tumour occur in?
Age 5-20yrs
42
What translocation is Ewing's tumour associated with?
t (11:22) (q24;q12)
43
Prognosis of Ewing's tumour?
5yr survival of >50%
| mets common but generally sensitive to chemo
44
What is multiple myeloma?
monoclonal gammopathy
bone marrow biopsy shows inc. plasma cells
multiple lesions on x-ray
45
Most common sites that mets to bone?
breast, bronchus, thyroid, kidney, prostate
46
Pathophysiology of mets to bone?
Usually promotes lytic activity causing bone destruction
| mets from prostate causes osteosclerotic action
47
Who do chondrosarcomas occur in?
middle aged and elderly (30-60)
90% arise de novo
10% from pre-existing chondroma
48
Where do chondrosarcomas occur?
Axial skeleton especially pelvis and ribs
49
What is Kaposi's Sarcoma associated with?
AIDs
| Human HPV 8
50
What is osteoporosis?
reduction in the actual amount of normally mineralised bone matrix
diagnosed by bone density scan
51
Who is osteoporosis common in?
Elderly, especially females (due to dec. in oestrogen post-menopause)
Steroid use
Cushing's syndrome
52
Blood chemistry in osteoporosis?
Usually normal
53
What causes Rickets and Osetomalacia?
deficiency of active metabolites of Vit D
54
Causes of osteomalacia?
```
elderly/housebound/institutionalised
dietary deficiency
malabsorption
anticonvulsants
chronic renal failure
```
55
Biochemistry of osteomalacia?
Calcium- normal or slightly low
Phosphate- often low
Alk Phos- often raised
56
Most common cause of primary hyperparathyroidism?
```
Parathyroid adenoma (80%)
Parathyroid hyperplasia
Parathyroid carcinoma (rare)
```
57
Effects of hyperparathyroidism?
```
hypercalcaemia
renal stone formation
metastatic calcification
peptic ulceration
pancreatitis
```
58
What bone disease does primary hyperparathyroidism cause?
Osteitis fibrosa cystica
| +/- brown tumour formation (hemosiderin)
59
Features of renal osteodystrophy?
secondary hyperparathyroidism
osteomalacia
osteosclerosis
soft tissue calcification
60
What frequently occurs in patients on dialysis?
deposition of aluminium in bone
severely inhibits mineralisation of bone
osteomalacia
61
What is Paget's disease of bone?
localised increase in bone turnover with disorderly bone remodelling
affected bones are thickened, soft and vascular
62
Features of Paget's disease of bone?
bone pain, deformities, deafness, fractures, nerve of spinal cord compression, osteosarcoma, high output cardiac failure
63
Blood chemistry of Paget's disease?
Calcium usually normal
| Alk Phos is markedly elevated
64
Where does Paget's disease usually affect?
lumbar vertebrae, sacrum, pelvis and skull
65
Benign skin neoplasms?
Squamous cell papillomas (wart)
Basal cell papilloma/ seborrheic keratosis
Melanocytic naevi
66
Types of melanocytic naevi?
```
junctional
compound
intradermal
blue
spitz
```
67
Genotype and phenotype of skin neoplasms?
```
White>Black
familial
Japan- feet, mucous membranes
Australia > Ireland
light skin, blue eyes, light or red hair, freckles, sunburn easily, tan with difficulty
```
68
What happens in solar elastosis?
inc. numbers of elastic fibres, fibres thicken and clump, disruption in collagen
directly associated with sun exposure
69
What is solar/actinic keratosis?
epidermal dysplasia in response to long-term UVB exposure
| can progress to SCC in situ or invasive SCC
70
Features of SCC in situ?
slightly raised, scaly, erythematous patch
severe epidermal dysplasia
no invasion through BM
71
Prevalence of skin neoplasms?
SCC (45%)
BCC (45%)
Adnexal tumours
MM (10%)
72
Features of SCC?
```
any part of body, esp. sun-exposed areas
may start as solar/ actinic keratosis
inc. with age
ulcer with raised edges
may mets (usually to LNs first)
```
73
BCC features?
recurrence (rodent ulcer)
hair-bearing skin, sun-exposed areas
inc. with age
pearly lesion, central ulceration, raised edges
islands of dark-staining basal-like cells
mitoses ++
locally invasive, never mets
74
When can BCCs be problematic?
locally invasive- can go to the eye and cause blindness
75
What does ABCDE stand for?
```
Asymmetry
Borders uneven
Colour multiple
Diameter >5mm
Evolving
```
76
Types of malignant melanoma?
lentigo melanoma
superficial spreading melanoma
nodular malignant melanoma
acral lentiginous malignant melanoma
77
Features of Lentigo Malignant Melanoma?
```
elderly, long-term sun exposure
skin atrophic, solar elastosis
pleomorphic melanocytes
in situ = confined to epidermis, invasive = dermis involvement
prognosis good (usually thin)
```
78
Features of superficial spreading melanoma?
any age
? short term sun exposure
pre-existing naevus
prognosis variable (depends on thickness)
79
Features of nodular malignant melanoma?
similar epidemiology to SSM
nodule
invasive -> dermis, no epidermal component
prognosis usually poor (depends on thickness)
80
Grading of Malignant Melanomas?
Breslow thickness
| Clark level
81
Clark level staging?
```
Level 1- epidermis
Level 2- papillary dermis
Level 3- filling papillary dermis
Level 4- reticular dermis
Level 5- subcutaneous fat
```
82
Prognostic factors in melanoma?
Breslow thickness
ulceration
mitotic rate
clark level
83
Mutations in melanoma?
BRAF (40-60%)
NRAS (10-15%)
KIT
84
Common skin infections?
Folliculitis
Furuncle (boil)
Carbuncle
85
What is folliculitis?
Infection of hair follicles
| common sites- axillae, buttocks, hips
86
Causes of folliculitis?
```
Staph aureus (most common)
Pseudomonas aeruginosa (hot tubs)
Candida (diabetes)
```
87
Treatment for folliculitis?
often unnecessary
| topical agents
88
What can folliculitis lead on to?
Furuncle or carbuncle formation
89
Causative agent for furuncles (boil) and carbuncles?
Staph aureus
90
Predisposing features for furuncles/carbuncles?
Diabetes
Steroid treatments
Immunosuppression
91
Treatment for furuncles/carbuncles?
flucloxacillin
erythromycin
good skin care
dressing of draining wounds
92
Causes of impetigo?
Strep pyogenes, Staph aureus
93
Who is impetigo most common in?
Children age 2-5yrs
94
Treatment for impetigo?
Topical mupirocin or retapamulin
| Oral flucloxacillin
95
What can follow impetigo?
Rarely can cause post-strep glomerulonephritis
96
What is erysipelas?
acute infection of upper dermis and superficial lymphatics (face and legs)
97
Features of erysipelas?
orange peel skin
sharply demarcated
painful
associated with lymphatic damage, diabetes
98
Treatment for erysipelas?
Benzyl penicillin
99
Treatment for scabies?
topical permethrin
| if severe oral ivermectin
100
Clinical manifestations of scabies infection?
itchy papules on fingers
erythematous papules on chest/abdomen
Norwegian crusts in immunocompromised
101
Main causes of cellulitis?
Staph aureus
| Group A streptococci
102
Diagnosis of cellulitis?
swabs of lesions
| blood cultures
103
Treatment of cellulititis?
Flucloxallin and Amoxycillin
104
Prevention of surgical wound infection?
```
aseptic technique
prophylaxis antibiotics (in exposure-prone surgery)
```
105
Two types of necrotising fasciitis?
Streptococcal (Group A)
| Mixed (anaerobes and coliforms)
106
Mortality of necrotising fasciitis?
20-50%
107
Causes of gas gangrene?
clostridia (most commonly clostridium perfringens)
108
Treatment of gas gangrene?
surgical emergency
surgical debridement (amputation)
benzyl penicillin and metronidazole
109
Treatment for tetanus?
antiserum and muscle paralysis
| ventilation
110
Cause of anthrax?
Bacillus anthracis
111
Treatment for anthrax?
ciprofloxacin
112
Causes of osteomyelitis?
Staph aureus
Pseudomonas aeruginosa (following penetrating injury to foot/heel)
Venous spread to vertebrae from bladder in elderly
Salmonella in Sickle Cell Disease
Haemophilus influenzae following bacteraemia
M. tuberculosis following extra-pulmonary spread
113
What tumour is associated with small round blue cells?
Ewing's sarcoma
114
What tests are useful in the diagnosis of RA?
Rheumatoid Factor
| Anti-citrullinated Peptide Antibody (ACPA)
