Acute Joint Pain 2 Flashcards
What are the crystals like in gout?
- urate crystals
- negatively birefringent
- needle shaped
- lots white cells (PMNs)
What are the crystals like in psuedogout?
- calcium pyrophosphate crystals
- positively birefringent
- rhomboid
How might septic arthritis show up in aspirate?
- cloudy aspirate with high WBC
- high neutrophil count
- bacteria visible on micrcosopy
- positive cultures
When might the WBCC be high in aspirate apart from septic arthritis?
crystal arthropathies
What would haemarthrosis suggest?
trauma with or without fracture
If fat gobules are present in aspirate what does this suggest?
fracture
If there is an absence of crystals, blood and infection but white cells present in aspirate what conditions could this suggest?
- reactive arthritis (Reiter’s syndrome)
- enteric arthropathy (due to IBD)
- rheumatoid arthritis
- psoratic arthritis
- rheumatic fever
What does non-inflammatory aspirate (clear with normal WCC) suggest?
trauma or osteroarthritis
Although arthrocentesis is the most appropriate 1st line treatment what other investigations can be considered for acute joint pain?
- cultures
- blood
- plain radiographs
- MRI
What swabs and cultures do you do and why?
skin lesions or throat, urethra, cervix and rectum if gonoccocal arthritis possibility
When would you do blood cultures?
of sus of sepsis
What bloods do you order for acute joint pain?
- FBC, CRP and ESR
- PT and APTT
- Rheumatological investigations
- Serum urate
Why do you do FBC, CRP and ESR?
- reveal any inflammatory or infective
2. osteomyelitis deranged ESR and CRP but not always raised WCC
When do you do PT and APTT?
if arthrocentesis reveal a haemarthrosis in absence of trauma sufficient should be requested to screen for coagulopathy
What rheumatological investigations can be requested?
- rheumatoid factor
- anti-CCP antibodies
- ANA
- other autoantibodies
When would you request serum urate?
non-acute setting
What can a plain radiograph show that otherwise may be hard?
- Unsuspected fracture
- Atraumatic avascular necrosis of femoral head (Perthe’s disease) or navicular in children (Kohlers disease)
- Effusion that not clinically obv (elbow)
- Erosion of joint surfaces from aggressive septic arthritis or inflammatory, autoimmune arhtropathy
- Chondrocaclinosis (pseudogout)
When would you carry out an MRI?
- If suspect soft tissue injury (meniscal tear in knee)
2. If suspect bony pathology not on XR (e.g. osteomyelitis
What joints does gout affect?
big toe and knee mostly
Even if you are really sure it is gout what else must you do?
gram stain and cultures to exclude septic arthritis
What medications are used in the acute treatment of gout?
- Colchicine
- NSAIDs
- Corticosteroid injection
When do you administer colchicine?
within 24hr
When is colchicine contraindicated?
renal or hepatic impairment
What are the side effect of colchicine?
severe GI side effect so use in low dose
When are NSAIDs contraindicated?
- peptic ulcer diseas
- acute or chronic renal failure
- heart failure
- pregnancy
- sometimes asthma
How are corticosteroids administered?
injected intro joint or given systemically
When are corticosteroids used?
patients who can’t take NSAIDs or colchicine
Why do you not give aspirin in gout?
can cause hyperuricaemia by impairing urate excretion (high dose fine) - but carry on taking as cardio risk arguable more important
For chronic treatment of gout what do you need to investigate for?
hyperuricaemia and if present prescribe medication
What medication can be prescribed for chronic gout and why?
- Decrease urarte production: allopurinol and febuxostat
- Increase urate excretion: sulfinpyrazone and probenecid
- Increase degradation of urate: rasburicase
How does allopurinol and febuxostat work?
inihibitors of xanthine oxidase and limit production of urate during degradation of nucelic acids
What are the contraindications of allopurinol and febuxostat?
dose must be reduced if renal or hepatic impairment and stopped if causes rash
What is co-prescribed with allopurinol?
colchicine co-prescribed with allopurinol for 6 weeks as initial dose of allu can result in acute gout
How does sulfinpyrazone and probenecid work?
inhibit reuptake of urate at PCT in kidneys, increasing urate excretion
When is sulfinpyrazone and probenecid used?
patient cannot tolerate allopurinol
When is rasburicase used?
uricase enzyme that adminsters to patients with severe hyperuricaemia due to chemotherapy
