[Rheum] Monoarthropathy Flashcards
what is your dx of a hot, swollen joint with a reduced ROM until proven otherwise?
septic arthritis (SA)
when should you aspirate the joint?
before abx therapy
what is the joint aspirate sent for?
3Cs and G (cells, culture, crystals and gram stain)
what do you start while waiting for results?
empirical IV abx based on likely organism
what is the most common causative organism for SA?
staph aureus
however, in high risk groups, gram -ve abx cover must be given
who are at high risk of gram -ve organisms causing SA?
- elderly
- recurrent UTIs
- recent abdominal surgery
- previous gram -ve bacteraemia
what is unique about prosthetic joint infections?
a biofilm adheres to them
what are prosthetic joint infections defined as?
- early (<3 months post surgery)
- delayed (>3 months post surgery)
what are delayed prosthetic joint infections more susceptible to?
coagulase -ve staphylococcus aureus
pt has a septic joint. what do you do next?
aspirate and send for 3Cs and G
pt has a septic joint and is sexually active. what else would you send for after joint aspiration?
gonococcal NAAT
after aspirating and sending off aspirate for 3Cs and G, what do you do next?
empirical IV abx and repeat joint aspiration until dry
there is bacterial growth on culture. what do you do next?
prescribe prolonged course of abx (local guidelines)
there is no bacterial growth on culture. what do you do next?
if purulent fluid (↑WCC) ⇒ re-aspirate joint
if non-purulent ⇒ consider other dx, stop abx
what is gout?
a crystal arthropathy where -ve birefringence MSU crystals are deposited in soft tissues e.g. joints
what are the risk factors for gout?
- purine rich diet
- obesity
- high ETOH intake
- DM
- chemotherapy / malignancy
- genetic defects of purine metabolism
how do you manage an acute attack of gout?
strong NSAID e.g. Naproxen until 1-2 days after the attack has settled + PPI gastric coverage
OR
colchicine for 5-7 days
how do you prevent another attack of gout: conservative mx?
- reduce ETOH intake
- lose weight
- reduce processed purine-rich foods
how do you prevent another attack of gout: medical mx?
urate lowering therapy (ULT):
- 1st line: allopurinol
- 2nd line: febuxostat
what do you need to co-start with allopurinol and why?
co-start with colchicine
allopurinol can paradoxically trigger an acute flare
urethritis, conjunctivitis and arthritis. dx?
reactive arthritis (can’t see, pee or climb a tree)
asymmetric polyarthralgia, tenosynovitis and skin lesions. dx?
gonococcal arthritis
HLA-B27 +ve. dx?
seronegative spondyloarthropathies
what is the pathophysiology behind gout?
urate crystal deposition in joints
what are the risk factors for gout?
obese, high ETOH and red meat consumption
what does the fluid aspirate for gout show?
- urate
- negatively birefringent needle shaped crystals
what is the rx for gout?
acute: NSAIDs / colchicine
chronic: allopurinol / febuxostat
what is the pathophysiology behind pseudogout?
calcium pyrophosphate (CPPD) deposition in joints
what are the risk factors for pseudogout?
- elderly
- hypothyroid
- hyperparathyroid
- electrolyte deficiencies
- haematochromatosis
what does the fluid aspirate for pseudogout show?
- calcium pyrophosphate
- positively birefringent
- rhomboid shaped crystals
what is the rx for pseudogout?
- NSAIDs / colchicine
- replace electrolytes if deficient
what is the pathophysiology behind reactive arthritis?
unknown exact aetiology
likely CD4+ T-cell autoimmune reaction
what are the risk factors for reactive arthritis?
- recent STI
- gastroenteritis
- HLA-B27
what does the fluid aspirate for reactive arthritis show?
- straw coloured
- WCC 2-100x10^9/L
- negative culture
what is the rx for reactive arthritis?
- treat underlying infection
- NSAIDs
- may need steroids/DMARDs
what is the pathophysiology behind haemarthrosis?
trauma, causing a haematoma in the joint
what are the risk factors for haemarthrosis?
- “recurrent fallers”
- anticoagulation
- post surgery
what does the fluid aspirate for haemarthrosis show?
blood
what is the rx for haemarthrosis?
correct coagulopathy
what is the pathophysiology of septic arthritis?
infection in the joint
what are the risk factors for septic arthritis?
- immunocompromised
- penetration injury
- overlying ulcerated skin
what does the fluid aspirate for septic arthritis show?
- purulent (WCC >100x10^9/L)
- bacterial growth on cultures
what is the rx for septic arthritis?
- aspirate to dryness
- IV abx based on cultures
