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MSK- Rheumatology > Crystal Arthropathies > Flashcards

Flashcards in Crystal Arthropathies Deck (64)
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1
Q

What are the two conditions which are classed as crystal arthropathies?

A

Gout and pseudogout

2
Q

What crystals are associated with gout?

A

Monosodium urate

3
Q

What crystals are associated with pseudo gout?

A

Calcium pyrophosphate

4
Q

How quickly do crystal arthropathies usually present and how long do they last?

A

Present acutely and last 2 weeks max

5
Q

What can repeated attacks of gout cause?

A

Destructive, erosive arthritis causing deformities

6
Q

What is a typical presentation of gout?

A

Intensely painful, red, hot, swollen joint

7
Q

Gout often mimics which other condition?

A

Septic arthritis

8
Q

Is gout inflammatory?

A

Yes

9
Q

What can the crystal deposition in gout be triggered by?

A

Dehydration, trauma or surgery

10
Q

Monosodium urate crystal deposition in gout is usually due to what?

A

Increased serum uric acid levels (hyperuricaemia)

11
Q

How common is gout?

A

The most common medical condition in adults of the industrialised world

12
Q

Which sex is gout most common in?

A

Men

13
Q

What is the relationship between gout and age?

A

Prevalence of gout increases with age

14
Q

What is the most common arthritis in men?

A

Gout

15
Q

What are the purines in DNA?

A

Adenine and guanine

16
Q

Where do purines in the body come from?

A

Breakdown of DNA or from the diet

17
Q

What are the breakdown stages from purine to uric acid?

A

Purine –> Hypoxanthine –> Xanthine –> Plasma urate –> Uric acid

18
Q

What enzyme is involved in changing purines to uric acid?

A

Xanthine oxidase

19
Q

What is lost during the process of changing purines to uric acid?

A

O2

20
Q

Can genetics increase the risk of gout?

A

Yes

21
Q

Uric acid is the final product in the breakdown of what?

A

Purines in DNA metabolism

22
Q

What are the two main causes of hyperuricaemia?

A

Under-excretion or over production

23
Q

What are examples of under excretion of uric acid?

A

Diuretic use, renal failure, starvation/dehydration, hypo/hyperparathyroidism, drugs, alcohol

24
Q

What are examples of over production of purines?

A

Excessive intake of alcohol, seafood, red meat, genetics or increased cell turnover

25
Q

What are some causes of high cell turnover?

A

Psoriasis, extreme diets, infections, anaemia, chemotherapy

26
Q

What defines hyperuricaemia?

A

Serum uric acid > 7mmol/dL

27
Q

What is the relationship between hyperuricaemia and gout?

A

Having hyperuricaemia does not mean you have gout, it just increases the risk of you getting it

28
Q

What are the three main sites of gout?

A
  1. 1st MTP (known as Podagra)
  2. Ankles
  3. Knees
29
Q

What is the diagnosis of gout based on?

A

Identification of crystals or classic radiographic findings

30
Q

What happens to uric acid to cause an acute of gout?

A

Acute changes in the levels of uric acid

31
Q

When is the best time to measure serum uric acid?

A

2-4 weeks following an acute attack

32
Q

Why should you not measure uric acid at the time of an acute attack?

A

25% of people can have a normal uric acid then

33
Q

What are three differential diagnoses of gout?

A
  • Septic arthritis
  • Trauma
  • Seronegative arthritis
34
Q

What is chronic polyarticular gout?

A

Chronic joint inflammation after having recurrent acute attacks of gout, often associated with diuretic use

35
Q

What is the gold standard investigation for gout?

A

Joint aspirate

36
Q

What other three investigations can be used for gout?

A

X-ray, inflammatory markers, WCC

37
Q

What will inflammatory markers show in gout?

A

Raised

38
Q

What will an x-ray show in gout?

A

Normal in acute attacks, erosions, osteophytes, joint destruction after recurrent attacks

39
Q

What is a joint aspirate?

A

A sample of synovial fluid with polarised microscopy

40
Q

As well as crystals, what else is investigated for during a joint aspirate?

A

The fluid us analysed with gram stain and culture to exclude infection

41
Q

What will gout show on joint aspirate?

A

Needle shaped crystals with negative birefringence (change from yellow to blue when lined across the direction of polarisation)

42
Q

What is the mainstay of treatment for an acute attack of gout if there are no contraindications?

A

NSAIDs

43
Q

If a patient with gout cannot have NSAIDs what should they use?

A

Colchicine

44
Q

What are the other two treatment options for the acute treatment of gout?

A

Steroids or stronger painkillers

45
Q

What lifestyle modifications can reduce gout?

A

Restrict risk factors, reduce alcohol, lose weight, fluids

46
Q

What are tophi?

A

Painless, white accumulations of uric acid which can occur in the soft tissues and occasionally erupt through the skin

47
Q

What are indications for prophylaxis of gout?

A
  • > 2 attacks
  • Tophi
  • Erosions on x-ray
  • Renal stones
48
Q

What are two examples of urate lowering therapies?

A

Allopurinol and febuxostat

49
Q

When should urate lowering therapy be started?

A

2-4 weeks following an acute attack

50
Q

Why should urate lowering therapy not be given while there is still an acute attack?

A

Can make it worse and potentiate a future flare

51
Q

What target serum urate should you be aiming for on urate lowering therapy?

A

< 0.3mmol/l

52
Q

What is pseudogout also known as?

A

Calcium pyrophosphate deposition disease (CPPD)

53
Q

Who does pseudo gout occur more commonly in? Why?

A

Elderly- chondrocalcinosis increases with age

54
Q

What is chondrocalcinosis?

A

Calcium pyrophosphate deposition in cartilage and soft tissues in the absence of acute inflammation

55
Q

Where does chonedrocalcinosis affect?

A

Fibrocartilage in the knees, wrists and ankles

56
Q

What is the relationship between pseudo gout and OA?

A

Pseudogout can occur when there is already OA, or chronic CPPD can cause OA

57
Q

How do you tell the difference between gout and pseudo gout?

A

Joint aspirate

58
Q

What will pseudo gout show on joint aspirate?

A

Rhomboid/envelope shaped crystals with weakly positive birefringence

59
Q

Is it possible to have both gout and pseudo gout?

A

Yes

60
Q

What diseases can pseudo gout co-exist with?

A

Hyperparathyroidism, hypothyroidism, renal osteodystrophy, haemochromotosis, Wilson’s disease

61
Q

What is the management for pseudo gout?

A

NSAIDs, colchicine, steroids, rehydration (only acute management here)

62
Q

What is Milwaukee shoulder?

A

Deposition of hydroxyapatite crystals in or around the joint

63
Q

What does Milwaukee shoulder cause and who is it mostly seen in?

A

An acute and rapid deterioration in females aged 50-60 years

64
Q

What is the only way to detect Milwaukee shoulder?

A

Alizarin stain will show red clumps