Crystal associated arthritis

Question 1

What are the risk factors for gout?

Answer 1

age 
males
obesity 
high protein diet 
high alcohol consumption (particularly beer) 
hyperlipidaemia, DM, IHD   and HTN
often a FH

Question 2

What joints does gout most commonly affect?

Answer 2

metatarsophalangeal joint of the big toe

small joints of the extremities

Question 3

What causes gout?

Answer 3

sustained increase in serum uric acid levels which leads to formation of urate crystals, which then deposit in the synovial, other connective tissues and the kidney. Joint inflammation occurs when the crystals are shed from the deposits within the joint.

most commonly caused by diuretic therapy

Question 4

How does acute gout present?

Answer 4

acute gout is extremely painful and typically presents with a rapidly accelerating monoarthritis, typically the first MTP joint
sudden onset including pain and severe swelling
skin overlying the joint is shiny, warm and red
joint is extremely tender

Question 5

How does acute gout progress?

Answer 5

attacks subside spontaneously within a few days to a couple of weeks
some patients will have no further problems but most will go on to have further attacks within a few years

Question 6

What are the ddx for acute gout?

Answer 6

Aeptic arthritis
Haemarthrosis
CPPD
Palindromic RA

Question 7

What investigations are used in gout?

Answer 7

Synovial fluid analysis
Serum uric acid levels
Radiology - x-ray may show erosions

Question 8

What is seen on synovial fluid analysis in gout?

Answer 8

shows urate crystals

gram stain and culture can be used to exclude infection

Question 9

What will the serum uric acid level be in gout?

Answer 9

well above normal (>600umol/L)

CRP, ESR are usually raised

Question 10

What is seen on x-ray in gout?

Answer 10

radiological changes may not occur until years after attack. Soft tissue swelling. opacities and rounded erosions in the joint margins may be seen

Question 11

What is the management plan for a patient with gout?

Answer 11

Analgesia - NSAIDs
Colchicine often gives GI SEs
Corticosteroids can be given if NSAIDs and colchicine are not tolerated. Steroids should not be used long term.

Question 12

What prophylactic therapy can be used to prevent further attacks of gout?

Answer 12

Urate lowering drugs - Allopurinol is most commonly used

This should not be commenced until acute attack has settled completely and NSAIDS or colchicine should be co-prescribed for the first few months. Use in low doses in renal impairment.

Question 13

How does Allopurinol work?

Answer 13

It reduces uric acid synthesis by inhibiting the enzyme xanthine oxide.

Should only be used when >1 attack in 12 months, tophi or renal stones

Question 14

What are the side effects of Allopurinol?

Answer 14

skin rashes and GI intolerance are the most common side effects
hypersensitivity reaction and bone marrow suppression is rare

Question 15

What are alternative urate lowering drugs?

Answer 15

Febuxostat - non-purine analogue inhibitor of xanthine oxidase. Well tolerated and as effective as allopurinol. Allopurinol should be trialled first.

Losartan

Uricosuric drugs (increased rate excretion, hepatotoxic)

Question 16

Which patients get chronic (tophaceous) gout?

Answer 16

individuals with high levels of uric acid who have recurrent attack of acute gout can present with chronic gout

Question 17

How does chronic gout present?

Answer 17

characterised by typhus formation and joint destruction.

sodium urate deposits in the soft tissue and forms tophi, which occur on the ear, in the fingers or the achilles tendon.

Question 18

How does chronic gout progress?

Answer 18

Tophi can interfere with function and sometimes ulcerate, discharging chalky white material. Cartilage destruction and bony erosions can lead to deformities.

Question 19

How is renal function affected in chronic gout?

Answer 19

Associated with renal impairment and/or use of long term diuretics
There may be acute or chronic rate nephropathy or renal stone formation

Question 20

How is chronic gout managed?

Answer 20

stop diuretics or change to less rate retaining ones (e.g. bumetanide)
treat with allopurinol +/- uricosuric agents

Question 21

What lifestyle advice can be given in the management of gout?

Answer 21

• Reduce alcohol intake (esp beer)
• Diet which reduces total calorie and cholesterol intake and avoids foods rich in purine
• Lose weight

Question 22

What is acute calcium pyrophosphate crystal deposition (pseudo gout) and how does it present?

Answer 22

attacks present with acute onset of joint pain, stiffness and swelling, sometimes accompanied by a fever
knee is most common site
attacks rarely affect more than one joint at a time and usually resolve within a few weeks

Question 23

What is calcium pyrophosphate dehydrate (CPPD) disease present?

Answer 23

CPPD disease is an arthropathy associated with deposition of calcium pyrophosphate dehydrate crystals. It can present as acute synovitis, often referred to a ‘pseudo gout’ or as chronic arthritis

Question 24

What is the pathology behind acute calcium pyrophosphate deposition?

Answer 24

shedding of crystals into a joint precipitates acute synovitis which resembles gout except it is more common in elderly women and usually affects the knee or wrist

MUST exclude septic arthritis and send joint fluid for culture

Question 25

What is seen on imaging/synovial fluid exam in calcium pyrophosphate deposition?

Answer 25

rhomboidal, weakly positive birefringent crystals in joint fluid or deduce for presence of chonedrocalcinosis on X-ray

Question 26

How does chronic pyrophosphate arthropathy present?

Answer 26

similar to OA
Onset is gradual
Symptoms: pain, early morning stiffness and loss of function
Commonly affect joints include knee,s, hips, shoulders, elbows, wrists and MCPs. Some patients develop acute attacks of synovitis

Question 27

How can chronic pyrophosphate arthropathy be distinguished from OA?

Answer 27

episodes of synovitis

involvement of the wrists, elbows and ankles

Question 28

What is chonedrocalcinosis?

Answer 28

calcification of cartilage, often seen in the menisci of the knee, triangular cartilage of the wrist and the symphysis pubis

Question 29

What does CPPD deposition in younger patients warrant?

Answer 29

unusual in younger patients so do a screen for metabolic disorders

Question 30

How should attacks of pseudo gout be treated?

Answer 30

analgesia - NSAIDs
joint aspiration and corticosteroid injection can provide rapid relief
colchicine can also be effective

Question 31

How should chronic pyrophosphate arthropathy be treated?

Answer 31

unlike gout there is no specific treatment, should be managed in a similar way to OA

emphasis on weight reduction, physiotherapy, pain control and joint replacement (if necessary)
synovitis episodes can be treated with steroid injections