MSK microbiology Flashcards
what is septic arthritis?
infection of joint space
what is septic arthritis caused by?
MSSA, strep
rare - h. influenza, neuseria gonorrhoea
how is septic arthritis spread
blood. contagious. direct
what investigations should be done in suspected septic arthritis
blood culture if fever CRP, FBC, U&Es, lactate etc joint fluid washout for culture, microscopy - crystals, WCC, gram stain US x-ray MRI bone scan CT
what are the symptoms of septic arthritis
acute monoarrhtropathy (inflammation on one joint at a time) decreased movement, swelling, systemic upset, increased WCC, increased inflam markers
what is osteomyelitis and where does it occur
inflammation/infection of bone and medullary cavity
long bone, vertebrae
may reoccur if treatment suboptimal
what are the causes of osteomyelitis
acute - mssa, strep
chronic - tb, psuedomonaks aeruginosa, salmonella esp in sickle cell patients, brucella - goats/cows milk, coliforms
how is osteomyelitis spread
blood, contiguous, PVD associated, prosthetic valve associated
what is the treatment of septic arthritis
if SA - flucoxacilllin high dose (IV)
in under 5 add ceftriaxone for HI and kingella cover
change when blood cultures come out
2-4 weeks
acute osteomyelitis - how long does it last for, what do infants have more of a risk of, what spread and where
few days to 2 weeks
infants are more at risk of septic arthritis
blood spread more likely
femur, tibia, shoulder, able, hip, elbow
chronic osteomyelitis - why, how long, treatment
if acute is not treated may progress
over 2 wks
is SIRS absent (usually is) then no need for immediate antibiotic treatment - wait till cultures
investigations for osteomyelitis
blood culture if fever
bony biopsy/wahsout
treatment of osteomyelitis
high flucox
modify w culture results
4-8 weeks of antibiotics
PJI risk factors
rheumatoid, diabetes, malnutrition, obesity
PJI 0-3 months is called what, symptoms and causes
early post op
fever, effusion, warmth drainage
SA, strep, enterococci
PJI 3-24 months is called what, symptoms and causes
delayed (low-grade)
persistant pain, device loosening, fistula
coag -ve staph
PJI >24 months. spread. types. causes
blood spread. can be acute or subacute. SA, e.coli
what ix for PJI
3 blood cultures
CRP
WCC
radiological investigations
treatment of PJI
retention of prosthesis - clean off boils and give gent
or replace 1 op
or 2 operations prosthetic removed, ABs, new prosthetic
or AB in high dose for long time
how many minimum weeks of ABs required before clean surgery for PJI
6
Prophylaxis - when is the first dose given, how long after surgery should dose not continue
first dose given within 60 mins of start of surgery
should not continue >24 hours after surgery
co-amox 1.2g peri op and 2 doses post op. PA co-trimoxazole
what should patients be screened for before op PJI
MRSA
What is given for PVL
clindamycin
what are the causes of BJI
SA, strep like group A, coliform, kingella in
presentation of BJI
temp/systemic signs
pain/redness/swelling over area
reduced mobility
children - listless, cranky, not feeding, not playing
SIRS
2 or more of
temp >38 or 90
RR>20 or PaCo2 12000 or under
presentation of cellulitis, causes, treatment
pain, swelling, erythema
B haemolytic strep, staph
rest, elevation, analgesia, split, panicillin
what is gas gangrene caused by? how does the process happen
clostridium perfringens - gram +ve strictly anaerobic rods which produces spore
spores get into tissues and germinate -> accumulate of gas bubbles in tissues ‘crepitus’
treatment of gas gangrene
urgent debridement
penicillin, metro - either or both
+/- hyperbaric oxygen in extreme cases
what is tetanus caused by? how does it present? treatment
clostridium tetanis. gram +ve strictly anaerobic rods. spore are found in soil, gardens, animal bites
lock jaw, muscle spasm due to toxins (non-invasive)
surgical debridement, anti toxins
penicillin/metro
booster vaccination - toxoid
