1: Crystal Arthritis Flashcards
(91 cards)
1
Q
What is crystal arthritis
A
arthritis caused by accumulation of crystals in one or more joints
2
Q
what are two types of crystal arthritis
A
- Gout
- Pseudogout
3
Q
what crystals are seen in gout
A
Uric acid ( monosodium urate crystals)
4
Q
what crystals are seen in pseudogout
A
calcium oxalate
5
Q
define gout
A
Inflammatory arthropathy due to deposition of uric acid crystals
6
Q
which gender does gout affect more
A
males (3:1)
7
Q
what age is peak incidence of gout
A
30-60y
8
Q
what ethnicity is gout most likely to occur in
A
African Americans
9
Q
what causes gout
A
Deposition of monosodium urate crystals in a joint
10
Q
what condition predisposes to gout
A
Hyperuricaemia
11
Q
where is uric acid produced
A
by metabolism of purines
12
Q
how is uric acid excreted
A
renal
13
Q
how may hyperuricaemia occur
A
due to increased production, metabolism or decreased excretion of uric acid
14
Q
How can the aetiology of hyperuricaemia be divided
A
- Increased production
- Decreased excretion
15
Q
what are the 3 categorical causes of hyperuricaemia
A
- High cell turnover
- Enzyme defects
- Products high in purines
16
Q
what are 4 causes of high cell turnover leading to hyperuricaemia
A
- Tumour lysis syndrome
- Myeloproliferative disorders
- Chemotherapy/Radiotherapy
- Haemolytic anaemia
17
Q
why does haemolytic anaemia cause hyperuricaemia
A
It is caused by a high-turnover of reticulocytes (which have nucleus, hence DNA and purines) and NOT RBC - as they have no nucleus.
18
Q
what enzyme defect can lead to hyperuricaemia
A
Lesh-Nyhan Syndrome
19
Q
what is lesh-nyhan syndrome
A
- Occurs solely in males
- Individuals present with behavioural and neurological abnormalities due to increased production of uric acid
20
Q
what are 4 products high in purines
A
Shellfish
Anchioves
Organ meat
Red meat
21
Q
what are 4 causes of decreased uric acid excretion
A
- Dehydration
- Chronic renal insufficiency
- Medications
- Acidosis
22
Q
what may lead to dehydration
A
- Decreased water intake
- Excess alcohol intake
23
Q
what are 3 medications that may cause hyperuricaemia
A
Thiazides
NSAIDs
Loop diuretics
24
Q
what may result in acidosis
A
DKA
Lactic acidosis
25
what are two risk factors for hyperuricaemia
Diabetes
| Obesity
26
How does hyperuricaemia present clinically
asymptomatic (can be asymptomatic for up to 20y)
27
How does gout present
- sudden-onset monoarticular joint pain reaches maximal intensity at 12h
- erythema, swelling and warmth of the joint
- decreased range of movement
- more likely at night
28
When is gout pain more common
nocturnal
29
what joint do 70% of gouty attacks affect
the first metatarsophalangeal joint
30
what is it called when gout affects the first meta-tarso phalangeal joint
Podgra
31
what is podgra
Gout of the first MTP joint
32
what is gonagra
Gout of the knee
33
what is chiragra
Gout of the first MCP joint of the thumb
34
what is chronic gouty arthritis
When recurrent acute attacks of gout lead to progressive degenerative arthritis
35
what may be seen in chronic gouty arthritis
Gouty tophi
36
what are gouty tophi
Painless hard nodules
37
when may bony tophi be seen
Deposition of monosodium urate within bone
38
when may soft tissue tophi be seen
Deposition of monosodium urate within soft tissues. Common site includes the ear
39
what are two renal manifestations of gout
Nephrolithiasis
| Uric acid nephrpathy
40
Explain pathophysiology of gout
Gout is due to hyperuricaemia, which results in sharp needle-like crystals. This accumulate in joints and renal tubules, reducing blood flow and hence causing damage
41
What are purines a component occurs
RNA + DNA
42
What happens when physiological cell destruction occurs
Purines are released and converse to uric acid
43
How is uric acid removed
in urine
44
When does hyperuricaemia occur
when production of uric acid exceeds its solubility in body fluids
45
how are monosodium urate crystals formed
in acidic conditions, uric acid looses a proton to become an ion which can then bind to sodium
46
What are 6 investigations ordered in gout
1. Arthrocentesis
2. FBC, CRP
3. US
4. MRI
5. Serum uric acid
6. X-ray
47
when is arthrocentesis indicated in gout
For all cases of acute gout
48
what is joint fluid sent for
Polarised light microscopy
49
what will be seen on polarised light microscopy in gout
Negatively birefringent monosodium urate crystals
(Remember as:
UR Negative)
50
what else will be seen in synovial fluid
WBC >2000
| Neutrophils >50%
51
how will serum uric acid present in gout
Raised
52
how will FBC, CRP be changed in gout
Raised
53
what may be seen on US in gout
Double contour sign
54
why may MRI be performed in gout
Identify tophi
55
when is an x-ray indicated for gout
Chronic gout. Not acute gout where there are recurrent attacks
56
what is a finding of chronic gout arthritis on x-ray
'punched-out' lesions
57
how can gout be differentiates from OA and RA on x-ray
```
OA = loss of joint space
RA = junta-articular osteopenia
```
- neither findings present in gout
58
How are acute attacks of gout managed
1. Advice + Self-Management
2. Colchicine or NSAIDs
3. Intra-articular corticosteroid injections or short-course oral corticosteroids
59
What advice should be offered in acute gout
- use ice packs (cold temp)
- Lifestyle changes
- Rest and elevate the limb
60
what medication is first line for gout
NSAIDs or Colchicine
61
what dose of NSAIDs should be given in gout and for how long
Start at a high dose for 1-2d. Prescribe with PPI
62
If individuals have co-morbidities and are unable to tolerate colchicine or NSAIDs, what should be offered
Short course oral corticosteroids or intra-articular corticosteroid injections
63
What should be offered to all individuals with a diagnosis of gout
Urate lowering therapies - to prevent attacks of gout
64
What are 7 indications in particular for urate lowering therapy
- More than 2 attacks in 12m
- Tophi
- Evidence arthritis
- Renal impairment
- Hx urate stones
- Diuretic use
- Young age first-onset
65
what is first-line urate lowing therapy
Allopurinol
66
explain dosing of allopurinol
Start at lowest dose an titrate up every 4W until serum uric acid is <300
67
what is second-line urate lowering therapy
Febuxostat
68
when is febuxostat indicated
If individual has CI or is not tolerating allopurinol
69
what should be checked prior to starting febuxostat
LFTs
70
what should be given when first staring all urate lowering therapies and why
Colchicine - as both urate lowering therapies increase risk of acute gout attacks once first started
71
how long is colchicine as prevention continued for
6 months
72
what are 3 complications of gout
- Gout arthritis
- Nephrolithiasis
- Tuberointerstitial nephropathy
73
what is pseudogout
arthritis caused by deposition of calcium pyrophosphate dihydrate (CPPD) crystals in joints
74
how is pseudogout characterised
recurrent attacks of mono arthritis
75
in which group if individuals does pseudogout occur more
Elderly
76
what causes pseudogout
1. Idiopathic
| 2. Secondary (see risk factors)
77
what are 6 risk factors for pseudogout
1. Haemochromatosis
2. Hyperparathyroidism
3. Low magnesium
4. Low phosphate
5. Wilson's disease
6. Acromegaly
78
how does pseudogout present clinically
Often asymptomatic and may be found incidentally on imaging
79
how will a pseudogout attack present
Sudden-Onset pain in monarticular large proximal joints
80
which type of joints does gout affect
first metatarsal-phalangeal (MTP) joint = podgra
81
which type of joints does pseudogout affect
large proximal joints
82
how does chronic pseudogout present
Osteoarthritis - with presence of calcium pyrophosphate dehydrate crystals
83
what are 3 differentiating features of psuedogout from gout
1. Positively befringent crystals
2. Affects large proximal joints
3. Older patients
84
what investigations may be performed in psuedogout
1. Joint aspiration
2. X-ray
3. Bone profile
4. Serum urate
85
what is performed on joint aspirate
Polarised light microscopy
86
what will polarised light microscopy show
Positively befringent rhomboid shaped crystals
87
what else will be present in synovial fluid
High WBC count
88
what will an x-ray show in pseudogout
Chrondrocalcinosis (calcification of the joint)
89
why may a bone profile be ordered in pseudogout
To check for calcium - if hyperparathyroidism
90
how are accessible joints affected by pseudogout treated
Intra-articular corticosteroids
91
how are inaccessible joints affected by pseudogout treated
Oral NSAIDs with PPI
Or, oral colchicine and paracetamol
