CP 56 - Bone and Joint Infections Flashcards
(23 cards)
what is osteomyelitis
infection of the bone
genetically what sort of infection is osteomyelitis
heterogeneous
what is the different types of pathogenesis for osteomyelitis?
- Haematogenous (bacteria in the blood seeds bone)
- Contiguous-focus (spread from adjacent area of infection)
- Direct inoculation ( trauma/surgery)
what are the classification of bone disease?
Stage 1 - medullary - necrosis medullary contents/endosteal surface (haematogenous)
Stage 2- superficial (necrosis limited to exposed surface (contiguous))
Stage 3 - full thickness cortical sequestation, stable before and after debridement (trauma, stage I/II evolving)
Stage 4 Diffuse – extensive, unstable bone
what is requried from stage 3 onward
surgery as no antibiotics can be delivered to the area and so it is essential to remove the dead area tp prevent furtehr espread
clinical presentation of osteomyelitis
Pain – presistent (soft tissue swelling) (erythema - redness of the skins) (warmth) (localised tenderness) reduced movement of affected limb systemic upset uncommon (fever, chills, night sweats - flu like symptoms)
what can cause osteomyelitis?
staphylococcus aureus, streptococci, enterococci, gram -ve bacilli (e.g Salmonella spp, Klebsiella spp, Pseudomonas aeruginosa – (in premature babies, intravenous drug users, sickle cell disease), anaerobes,
mycobacterium tuberculosis, brucella spp
how can osteomyelitis be diagnosised
gold standard - cultures and histology of bone biopsy/needle aspirate
treatment for osteomyelitis
antimicrobials +/- surgery depending therapy if possible
what anitmicrobials can be used to treat osteomyelitis?
Clindamycin(streptococci), ciprofloxacin, vancomycin, ß-lactams and gentamicin achieve acceptable levels in bone
Flucloxacillin IV – agent of choice for staphylococcus aureus osteomyelitis
definition of spetic (infective) arthritis
Inflammatory reaction in joint space (arthritis) caused by infection - result from direct invasion of the joint
what are the 2 types of septic arthritis?
native ( natural) joint infection, prosthetic (artifical) joint infection
pathogenesis of spetic arthritis especially in the native joint infection
- Organisms enter a joint via the blood (haematogenous) or trauma (e.g. surgery or injection)
- Synovial tissue is highly vascular and lacks a basement membrane - ?facilitating “seeding”
what are the predisposing factors for native spetic arthritis
rheumatoid arthritis, trauma, intravenous drug use, immunosuppressive disease
pathogenesis of spetic arthritis especially in the prosthetic joint infection
- Organisms enter a joint via the blood (haematogenous), during surgery or following wound infection
- Joint prosthesis and cement provide a surface for bacterial attachment
what are the predisposing factors for prosthetic spetic arthritis?
prior surgery at the site of the prosthesis, rheumatoid arthritis, corticosteroid therapy, diabetes mellitus, poor nutritional status, obesity, and extremely advanced age
clinical presentation for spetic arthritis
- joint - pain, swelling, tenderness, redness and limitation of movement,
- systemic upset - flu like symtpoms
what organisms can cause spetic arthrisit?
bacteria, fungi eg candida spp. , virus eg Parvovirus B19, Rubella virus, Mumps virus – can cause arthritis – usually self limiting part of systemic illness.
what are the common causative organism for native septic arthritis?
haemophilus influenzae, neisseria gonorrhoae, neisseria meningitidis
what are the common causative organism for prosthetic septic arthritis?
coagulase -ve staphylococci (CoNS), enterococci, corynebacteria, propionibacteria, bacillus spp.
how can spetis arthritis be diagnosed using lab techniques?
total white cell count - >40 000/m3 drug infection, differential WCC, gram stain, crystal exam, culture
treatment for native septic arthritis
- removal of purulent material - joint drainage/washout
- antimicrobial therapy - duration 2-4 weeks for native joint
treatment for prosthetic septic arthritis
- removal of implant or replacement of some element, washout
- antimicrobial therapy - duration 6 weeks
