Acute Joint Pain 2

Question 1

What are the crystals like in gout?

Answer 1

1. urate crystals
2. negatively birefringent
3. needle shaped
4. lots white cells (PMNs)

Question 2

What are the crystals like in psuedogout?

Answer 2

1. calcium pyrophosphate crystals
2. positively birefringent
3. rhomboid

Question 3

How might septic arthritis show up in aspirate?

Answer 3

1. cloudy aspirate with high WBC
2. high neutrophil count
3. bacteria visible on micrcosopy
4. positive cultures

Question 4

When might the WBCC be high in aspirate apart from septic arthritis?

Answer 4

crystal arthropathies

Question 5

What would haemarthrosis suggest?

Answer 5

trauma with or without fracture

Question 6

If fat gobules are present in aspirate what does this suggest?

Answer 6

fracture

Question 7

If there is an absence of crystals, blood and infection but white cells present in aspirate what conditions could this suggest?

Answer 7

1. reactive arthritis (Reiter’s syndrome)
2. enteric arthropathy (due to IBD)
3. rheumatoid arthritis
4. psoratic arthritis
5. rheumatic fever

Question 8

What does non-inflammatory aspirate (clear with normal WCC) suggest?

Answer 8

trauma or osteroarthritis

Question 9

Although arthrocentesis is the most appropriate 1st line treatment what other investigations can be considered for acute joint pain?

Answer 9

1. cultures
2. blood
3. plain radiographs
4. MRI

Question 10

What swabs and cultures do you do and why?

Answer 10

skin lesions or throat, urethra, cervix and rectum if gonoccocal arthritis possibility

Question 11

When would you do blood cultures?

Answer 11

of sus of sepsis

Question 12

What bloods do you order for acute joint pain?

Answer 12

1. FBC, CRP and ESR
2. PT and APTT
3. Rheumatological investigations
4. Serum urate

Question 13

Why do you do FBC, CRP and ESR?

Answer 13

1. reveal any inflammatory or infective

2. osteomyelitis deranged ESR and CRP but not always raised WCC

Question 14

When do you do PT and APTT?

Answer 14

if arthrocentesis reveal a haemarthrosis in absence of trauma sufficient should be requested to screen for coagulopathy

Question 15

What rheumatological investigations can be requested?

Answer 15

1. rheumatoid factor
2. anti-CCP antibodies
3. ANA
4. other autoantibodies

Question 16

When would you request serum urate?

Answer 16

non-acute setting

Question 17

What can a plain radiograph show that otherwise may be hard?

Answer 17

1. Unsuspected fracture
2. Atraumatic avascular necrosis of femoral head (Perthe’s disease) or navicular in children (Kohlers disease)
3. Effusion that not clinically obv (elbow)
4. Erosion of joint surfaces from aggressive septic arthritis or inflammatory, autoimmune arhtropathy
5. Chondrocaclinosis (pseudogout)

Question 18

When would you carry out an MRI?

Answer 18

1. If suspect soft tissue injury (meniscal tear in knee)

2. If suspect bony pathology not on XR (e.g. osteomyelitis

Question 19

What joints does gout affect?

Answer 19

big toe and knee mostly

Question 20

Even if you are really sure it is gout what else must you do?

Answer 20

gram stain and cultures to exclude septic arthritis

Question 21

What medications are used in the acute treatment of gout?

Answer 21

1. Colchicine
2. NSAIDs
3. Corticosteroid injection

Question 22

When do you administer colchicine?

Answer 22

within 24hr

Question 23

When is colchicine contraindicated?

Answer 23

renal or hepatic impairment

Question 24

What are the side effect of colchicine?

Answer 24

severe GI side effect so use in low dose

Question 25

When are NSAIDs contraindicated?

Answer 25

1. peptic ulcer diseas 2. acute or chronic renal failure 3. heart failure 4. pregnancy 5. sometimes asthma

Question 26

How are corticosteroids administered?

Answer 26

injected intro joint or given systemically

Question 27

When are corticosteroids used?

Answer 27

patients who can't take NSAIDs or colchicine

Question 28

Why do you not give aspirin in gout?

Answer 28

can cause hyperuricaemia by impairing urate excretion (high dose fine) - but carry on taking as cardio risk arguable more important

Question 29

For chronic treatment of gout what do you need to investigate for?

Answer 29

hyperuricaemia and if present prescribe medication

Question 30

What medication can be prescribed for chronic gout and why?

Answer 30

1. Decrease urarte production: allopurinol and febuxostat 2. Increase urate excretion: sulfinpyrazone and probenecid 3. Increase degradation of urate: rasburicase

Question 31

How does allopurinol and febuxostat work?

Answer 31

inihibitors of xanthine oxidase and limit production of urate during degradation of nucelic acids

Question 32

What are the contraindications of allopurinol and febuxostat?

Answer 32

dose must be reduced if renal or hepatic impairment and stopped if causes rash

Question 33

What is co-prescribed with allopurinol?

Answer 33

colchicine co-prescribed with allopurinol for 6 weeks as initial dose of allu can result in acute gout

Question 34

How does sulfinpyrazone and probenecid work?

Answer 34

inhibit reuptake of urate at PCT in kidneys, increasing urate excretion

Question 35

When is sulfinpyrazone and probenecid used?

Answer 35

patient cannot tolerate allopurinol

Question 36

When is rasburicase used?

Answer 36

uricase enzyme that adminsters to patients with severe hyperuricaemia due to chemotherapy