septic arthritis

Question 1

joint knee aspirate with Gram-positive cocci tx

Answer 1

The BNF currently recommends flucloxacillin or clindamycin if penicillin allergic

normally be given for several weeks (BNF states 4-6 weeks)
patients are typically switched to oral antibiotics after 2 weeks

Question 2

what is seen in aspiration of gout?

Answer 2

Synovial fluid analysis
needle shaped negatively birefringent monosodium urate crystals under polarised light

pseudogout
joint aspiration: weakly-positively birefringent rhomboid-shaped crystals
calcium pyrophosphate crystals

Question 3

rik factors for septic arthritis?

Answer 3

Risk factors include age over 80 years,
diabetes mellitus,
previous joint prosthesis, rheumatoid arthritis, immunosuppression / HIV infection, and also intravenous drug use.

Question 4

organism commonly causing septic arthritis?

Answer 4

Staphylococcus aureus
in young adults who are sexually active, Neisseria gonorrhoeae is the most common organism

Other staphylococci and streptococci can also cause septic arthritis

most common route of infection is via haematogenous spread, but it can also result from direct local infectious spread or recent instrumentation.