Bone and Joint Infections (musculoskeletal pathology) Flashcards
What is infection of bone known as?
Osteomyelitis
How does infection spread to the bone?
1) Haematogenous ( bacteria accesses the bone via the blood stream)
2) Contiguous focua (infection spreads from a local site e.g. diabetic ulcer can spread to infect the adjacent bone)
3) Direct inoculation (during trauma or surgery pathogen has direct access to bone)
How is osteomyelitis classified and what are the causes of each stage?
Stage 1 = Medullary :
-necrosis of the medulla (usually caused by haematogenous spread)
Stage 2 = Superficial:
Necrosis of periosteum (caused by contiguos spread from local infection)
Stage 3 = Localised
Necrosis of cortical bone (infection caused by trauma)
Stage 4 = Diffuse
Extensive necrosis - major desruction needs reconstructive surgery
How does osteomyelitis present clinically?
- pain (persistent, worse at night)
- Soft tissue swelling
- Erythema
- warmth
- reduced movement of limb
- systemic upset - flu like symptoms
What are the common causative organisms of osteomyelitis?
- Staphylococcus Aureus (most common)
- Streptococci
- Enterococci
- Gram negative Bacilli e.g. Salmonella
- Anaerobes
- Mycobacterium Tuberculosis
How is osteomyelitis treated?
- Flucloxacillin (treatment of choice for Staph Aureus osteomyelitis)
- Clindamycin (for staph aureus)
- Ciprofloxacin (for gram -ve)
- Vancomycin (alternative for beta lactams, for penicillin allergy)
What is septic (infective) arthritis?
Inflammatory reaction in joint space caused by infection.
results from direct invasion of the joint.
Can be native (natural) joint infection or prosthetiv
what are the pre-disposing factors for Native septic arthritis?
- Rheumatoid Arthritis
- trauma
- IV drug use
- immunosuppressive disease
What are the pre-disposing factors fro prosthetic septic arthritis?
- prior surgery at site of joint
- rheumatoid arthritis
- corticosteroid therapy
- diabetes mellitus
- poor nuitriton
- obesity
- age
How does septic arthritis present clinically?
- Joint pain , swelling,redness, limited movement
- Flu like symptoms
What are the causative organisms of Septic Arthritis?
give examples for both native and prosthetic
- Bacteria
- Fungal (candida)
- Virus (rubella, mumps)
Native joint:
- Staphylococcus Aureus
- Streptococci (A, B , C , G)
- Haemophilus influenzae ( reduced due to vaccine)
- Gram negative bacilli (e.g. E.Coli)
- N.Gonorrhoea
- N.Meningitidis
- Anaerobes
- Mycobacterium
Prosthetic:
- Staph aureus
- Streptococci (A, B, C, G)
- Gram negative bacilli
- Anaerobes
- mycobacteria
- Normal Skin flora e.g. (enterococci, corynbacteria, propionibacteria, bacillus)
How are native joint infections treated?
-removal of pus
-antibiotics
(2-4 weeks)
How are prosthetic joint infections treated?
-removal of implant (replaced after infection has gone)
-antibiotics
(duration 6 weeks)
What is the most common bacterial pathogen that causes joint infection?
Staphylococcus Aureus
