Bone Infection Flashcards
What does a ‘heterogenous’ disease mean?
Can be caused by lots of organisms and at lots of different sites!
What does haematogenous mean?
Infection spreading via the blood stream, may be a primary focal point of Infection.
What does contiguous focus spread mean?
Spread of Infection adjacent to bone - eg ulcers
Stage 1 osteomyelitis is know as what?
Medullary - confined to medulla of bone often due to haematogenous.
Stage II osteomyelitis is also known as and involves?
Superficial - necrosis is limited to the exposed surface.
Stage III osteomyelitis is and causes?
Localised- full thickness cortical sequestration, needs debridement island of bone is left.
Stage IV osteomyelitis?
Diffuse and extensive unstable bone.
What are the most common symptoms of osteomyelitis?
Localised pain Soft tissue swelling Erythema Nocturnal pain - waking with pain Reduced movement Progressive pain
Which symptoms are uncommon in osteomyelitis?
Systemic illness, such as fever and chills
At least 60% of osteomyelitis is caused by what organism?
Staph Aureus
Causative organisms in osteomyelitis (6)?
Staph, Strep, TB, Enterococci, gram neg and anaerobes.
What % of blood cultures are positive in osteomyelitis?
~50%
Gold standard for diagnosing osteomyelitis?
Culture and histology of bone/aspirate.
What type of therapy should be avoided in osteomyelitis?
Empirical treatment.
What method of administration is best for ABX?
IV penetrate bone
Antibiotics that penetrate bone well (5)?
Clindamycin (staph), ciprofloxacin (gram neg) Vancomycin (IV) beta lactams, gentamicin
Staph aureus osteomyelitis treatment of choice ?
IV Flucloxacillin!
Joint Infection occurs via what mechanism?
Haematogenous or trauma/surgery.
What factors predispose to septic arthritis?
Rheumatoid arthritis, trauma, IV drug use and immunosuppressive disease.
Predisposing factors for prosthetic joint infection?
Rheumatoid arthritis, prior surgery, steroid therapy, diabetes, poor nutrition, obesity, advanced age.
Presentation of septic arthritis?
Pain, swelling, limitation of movement, systemic upset such as fever, chills sweats.
Causative organism for septic arthritis?
Candida
bacteria- staph, strep, gram neg, anaerobes and myco tb
virus- rubella, parvo, mumps (usually self limiting)
Native joint infection organisms?
Haemophilus influenzae, strep pyogenes, neisseria goborrhoea, neisseria meningitidis
Prosthetic joint organism?
Coagulate negative staph, enterococci, corynebacteria, bacillus, propionibacteria (not usually severe normal flora low grade)
Joint aspirate for septic arthritis what to look for?
White cell- >40k
WCC > 75% polymorphs
Crystal exam for gout
Therapy for native joint infection?
Empirical ABX if needed
Joint washout
2-4 weeks therapy (native)
Prosthetic infection therapy?
Removal if unstable joint
Washout possibly
Flucloxacillin + rifampicin for s aureus
Never give which antibiotic alone for staph?
Rifampicin
Which antibiotic combination for coagulate negative staph septic infection?
Rifampicin plus vancomycin can also be used for penicillin allergic.
