Microbiology Flashcards
Three anatomical locations of infection in MSK
Bone, Joint + synovial, Muscle Infections
Do what before treating bone
take sample
how to treat septic patients
empirically
Osteomyelitis
Inflammation of bone and medullary cavity (usually long bone). Acute/chronic, contiguous/haematogenous. May recur after treatment.
Treatment of osteomyelitis
debridement and ABs
Diagnosis of osteomyelitis
History > Bone Biopsy (gold standard) > Treat with ABs (await microbiology 2 days)
Loves colonising prosthetic materials
Staph epidermidis
Treat staph aureus with
flucloxacillin
treat staph epidermidis with
vancomycin
Dealing with Open fractures
Early management (aggresive debridement, fixation and soft tissue cover). Staph aureus + aerobic gram -ve bacteria.
Diabetes/ Venous Insufficiency
Ofetn polymicrobial. Probe to bone to diagnose. Treat with debreidement and ABs
Haematogenous Osteomyelitis
USually prepubertal children, PWIDs, Central lines/ dialysis/ elderly. Treatment is surgical. History > Bone Biopsy (gold standard) > treat with ABs (await dagnosis)
Bacteria associated with Dialysis
staph aureus
Osteitis Pubis
triggered by surgery, athletes can get it
Clavicle Osteomyelitis
3% of osteo, risk factors of neck surgery and subclavian vein catheterisation
Sickle Cell Osteo
Infarction of bone. STaph Aureus + Salmonella
Gaucher’s Disease
Staph Aureus
Vertebral Osteomyelitis
Mostly haemotegenous: PWID, IV sites, GU infections, SSTI, Post Op. CT guided bone biopsy. 90% have insidious pain, 90% raised inflammatory markers, MRI needed to be sure.
Treatment of vertebral osteomyelitis
Drainage of large paravertebral/ epidural abscesses. ABs fro 6 weeks.
Prosthetic Joint Infection risk factors
Rheumatoid arthritis, diabetes, malnutrition, obesity
Prosthetic joint infection presentation
early = within month (haematoma/ wound sepsis) late = >month (contamination at time of operation)
Prostehetic joint infection diagnosis + treatment
Staph aureus (fluclox) Staph epidermis (Vancomycin). Treat by removing prosthesis, re-implantation following aggressive AB therapy.
Septic Arthritis
Inflammation of joint space by infection. Direct invasion through wound, haematogenous spread, cellulitis, abscess, spread from osteomyelitis
Septic arthtritis bacteria
Staph aureus, Streptococci, coag -ve staph (prosthesis), neisseria gonorrheae (sexually active)
Septic Arthritis Diagnosis
Classic inflammation > microscopy of joint fluid > blood culture (if pyrexial) > exclude crystals
Septic arthritis treatment
presume flucloxacillin (add ceftriaxone if <5 yrs)
Pyomyositis
Infection of muscle. 90% staph, requires debridement.
Tetanus
Clostridium tetani, gm +ve anaerobic rods. Spores (in gardens, soil e.g. soldie in trenches). Binds to inhibitory neurones, preventing release of neurotransmitters. Muscles spasms can impinge breathing so high level of care.
Tetanus treatment
Surgical debridement, antitoxin, supportive, ABs (penicillin/ metronidazole, controversial as it is a toxin not bacteria)
