MSK L10 Bone and Joint Infections Flashcards
Endodontic and periapical dental abscessess:
- Oral anaerobic bacteria usually predominate, multiple species the norm.
- Streptococus intermedies [milleri] often present.
- Bacteria usually antibiotic sensitive, but drain abscess if possible
Causes of chronic monoarticular arthritis:
- Mycobacterium tuberculosis
- Other mycobacteria (M. Kansasii, M. marinum, M. intracellulare, M. fortuitum, M. leprae)
- Brucella species
- Nocardia asteroids
- Fungi (Sporothrix schencki, coccidioides immitis, Blastomyces dermatitidis, Candida albicans, Pseudoallesscheria boydii).
Spinal tuberculosis → Pott disease/tuberculous spondylitis
- Advanced case → Gibbus deformity
- Paravertebral swelling and destruction of intervertebral disc
- Fusion of vertebrae
Arthritic symptoms after infection at distant site
- Gastroenteritis (salmonella, shigella, Yersinia and Campylobacter)
- Sexually acquired infections (Chlamydia, Ureoplasma, Gonorrhoea)
- Sore throat (streptococcus pyogenes)
- Viral infections (influenza, parovirus, hepatitis B and C)
Reactive arthritis (reiter’s disease) Often associated with
Conjunctivitis and/or urethritis
Reactive arthritis (reiter’s disease) Associated with
HLA-B27
Osteomyelitis (OM): definition →
An inflammatory process accompanied by bone destruction caused by an infecting micro-organism.
Osteomyelitis (OM): definition → Can involve
Can involve one or several of cortex, marrow, periosteum and adjacent soft tissue.
Osteomyelitis (OM): definition → Spread to
Soft tissue and joints, generalized infection or sepsis
Waldvogel osteomyelitis classification:
Acute and chronic osteomyelitis resulting from:
- Contiguous spread from contaminated source following trauma, surgery, joint replacement, wound infection.
- Vascular insufficiency with infected soft tissue wounds (esp. diabetic feet).
Factors increasing susceptibility: (and response to treatment) Systemic
- Malnutrition
- Renal or liver failure
- Diabetes melitis
- Immune defiency
- Chronic hypoxia
- Malignancy
- Extremes of age
Factors increasing susceptibility: (and response to treatment) Local
- Chronic lymphedaema
- Venous stasis
- Blood vessel compromise
- Arthritis
- Extensive scarring
- Radiation fibrosis
- Loss of local sensation
- Tobacco abuse
Haematogenous osteomyelitis (Childhood)
Haematogenous osteomyelitis (Adults):
Sickle cell disease Intravenous drug abusers Vascular insuffiency Post traumatic osteomyelitis Chronic Osteomyelitis
- Acute haematogenous OM mainly a disease of childhood.
- Growing pains of long bones esp. femur and tibia particularly susceptible.
- Children
Haematogenous osteomyelitis (Adults):
- Unusual in adults
- Vertebrae most common site once long bones stop growing
- Aetiology:
a. Staph aureus
b. Strept spp.
c. Gram Neg bacilli
d. Mycobacterium tuberculosis
Sickle cell disease
Gram negative rods, esp. salmonella enterica and Proteus mirabilis
Staphylococcus aureus
Staph pneumoniae
Intravenous drug abusers
Gram negative bacilli inc. Pseudo auruginosa Staph aureus Coagulase –ve staphylococci Staph aureus Candida
Vascular insuffiency
Aetiology reflects soft tissue origins:
- Staph aureus
- Streptococcis spp.
- Enterococcus spp.
- Gram negative bacilli
- Anaerobes
Post traumatic osteomyelitis
Aetiology consistent with wound infections:
- Staphylococcus aureus
- Polymicrobial (mixed)
- Gram negative bacilli
- Anaerobes
Chronic Osteomyelitis
Usually untreated acute osteomyelitis:
- Sinus tracts and extension to adjacent soft tissue may develop
- Fragmentation of dead bone → sequestra (devitalised segments)
- Fibroblast proliferation and new bone development may envelope affected area → involucrum
- Dense fibrous capsule surrounding localised infection (pus) = brodie’s abscess
Diagnosis of bone and joint infection: Symptomatic
- Systemic toxaemia (fever)
- Local inflammation
- Loss of function (load bearing)
Diagnosis of bone and joint infection: Investigations
- Blood cultures
- Culture of aspirated joint fluid/pus or bone biopsy (sinus cultures dubious)
- Radiological examiantionL x-rays, isotopic bone and MRI scanning
Diagnosis of bone and joint infection: Other laboratory tests
- Septic arthritis → ESR, CRP and white cell count are elevated, but may be elevated in non-septic arthritis also
- Acute OM → ESR, CRP and white cell count are elevated but WCC rarely >15,000/mm3
- Chronic Om → ESR, CRP modestly elevated
Antibiotics with anti-staphylococcal properties and good penetrative properties e.g.
- flucloxacillin and other beta-lactams
- Clindamycin/erythromycin
- Fluoroquinolones e.g. ciprofloxacin
- Rifampicin may be added for anti-biofilm activity
2009 UHB policy (empirical iv therapy)
- Benzylpenicillin = Flucloxacillin + gentamicin
Or - teicoplanin + Gentamicin (if pen allergic or MRSA suscepted)
Treatment of Bone and Joint infection:
Antibiotics with anti-staphylococcal properties and good penetrative properties e.g.
2009 UHB policy (empirical iv therapy)
Effective drainage of purulent synovial fluid
Surgery necessary to remove necrotic bone in OM if not treated early or response to antibiotics is poor (chronic OM)
Immobilization
