Septic Arthritis

Question 1

pathophys of septic arthritis?

Answer 1

most common overall: s. aureus
young sexually active: n. gonnorrhoeae

most commonly haematogenous spread (maybe from distant bacterial infections - e.g. abscesses)

Question 2

joint most commonly affected in septic arthritis?

Answer 2

knee

can affect hip, ankle
does not usually affect wrist

Question 3

features of septic arthritis?

Answer 3

acute, swollen joint (restricted movement in 80%)
fever in most pt

exam: warm to touch/fluctuant

Question 4

ix of septic arthritis?

Answer 4

synovial fluid sampling OBLIGATORY - prior to administration of abx if necessary, maybe under radiographic guidance

blood cultures - as most due to haem. spread

joint imaging

Question 5

mx of septic arthritis?

Answer 5

IV abx (covering gram + cocci) = flucloxacillin or clindamycin if pen allergic
normally for several wks (4-6)
pt switched to oral after 2wks

needle aspiration to decompress joint

arthroscopic lavage maybe required

Question 6

how to differentiate pt with renal disease: gout or septic?

Answer 6

although renal disease increases gout risk
septic - systemic unwellness

Question 7

features that would point to SA?

Answer 7

acute, hot swollen knee
IVDU
fever, inability to WB, raised inflammatory markers

Question 8

features that would point to SA?

Answer 8

acute, hot swollen knee
IVDU
fever, inability to WB, raised inflammatory markers

Question 9

what is flucloxacillin often used for?

Answer 9

first-choice for MSK and soft tissue infections in those with no allergies

Question 10

when would vancomycin be used in SA?

Answer 10

if strain was MRSA

Question 11

when would ceftriaxone or cefotaxime be used in SA?

Answer 11

if bacteria was gram -
or pt was young with gonococcal artheritis