osteomyelitis and septic arthritis Flashcards
most common joint in septic arthrirtis
knee
septic arthritis how many joints
90% only one joint
tell-tale difference between chronic and acutre septic arthritis
chronic normally non-pyogenic
septic arthritis main risk factor. why
age iatrogenic
most common pathogenesis septic arthritis
haematogenous. blood-borne bacteria gets into joint somehow
most common pathogen septic arthritis
staph aureus
which bacteria can cause septic arthritis in <1 year olds (2)
HIB, haemophilus because pre-vacc
which STD can cause septic arthritis
gonorrhoea
investigations and results for septic arthritis
Elevated ESR (or CRP)
Neutrophilia (esp. in children)
Joint (synovial) fluid examination
Turbid or purulent
Leukocytes >50,000/mm3, pred. neutrophils
Gram stain positive in one-third
<25mg/dL glucose (much lower than serum)
Blood culture positive in one- to two-thirds
what do you get in mycobacterial septic arthritis if left untreated
Joint space narrowing
Effusion
Erosions
Cyst formation
what do you see accumulating here
fluid with osteomyelitis, Baker’s cyst
tx for septic arthritis
3-4 weeks IV abx
describe reactive (Reiter) arthritis
sterile arthritis normally post-infection
sausage toes and flaky skin, urethritis, uveitis
can’t see, can’t pee, can’t climb a tree
genetic rf for reactive arthritis
HLA-B27
which bones does tuberculosis normally infect first
vertebrae, also SI joint and hips via iliopsoas
imporant rf for osteomyelitis (think impaired blood supply)
DM and sickle cell
what might you see in an infected joint replacement (5)
lucencies at bone-cement interface
changes in component position
cement fractures
Periosteal reactions
gas in joint
gold standard tx for failed joint replacement
removal of prosthesis, antibiotics for 6wks, re-implantation of new prosthesis 4 weeks after removal - 90%+ success
what is Pott’s disease
hunchback of notre dame
TB goes into spine, causing hump
