Osteomyelitis

(OM)

<Presentations>

<Index>

 

 

Definition

-  Infection of bone

 

Features

-  Should be clinically suspected & excluded in open infected wound w bone on view

-  Esp if fracture

-  Chronic osteomyelitis

-  Sequestra = separated dead bone due to pressure ischaemia from exudate

-  Involucrum = new bone formation in area of periosteal damage

 

Associated S/S

-  Fever

-  +/- Surrounding cellulitis

-  Pain, swelling

-  +/- Sinus tracts

-  Wounds probing to bone

 

Risk Factors

-  DM

-  Immunosuppression

-  Vasculopathy

-  Surgery

-  Ulcers: decubitus, diabetic..

-  Septic arthritis

-  Prosthesies

 

Complications

-  Tumours ass w chornic osteomyelitis: SCC, fibrosarcoma, myeloma, lymphoma..

 

Mechanism

-  Haematogenous

-  More common in keds, usually to long bones

-  Long bones typically effected at metaphysis

-  Adults usually to axial skeleton: vertebrae..

-  Usually monomicrobial

-  Direct inoculation: trauma, surgery

-  Spread from contiguous structure: septic arthritis, ulcers, infected prosthesies

 

Cause

-  Staph aureus 80%

-  +/- Coag negative Staph

-  Enteric Gram –ves

-  Esp vertebral OM

-  Hib: children <5yrs not immunised

-  Kingella kingae infants & children

-  Usually ploymicrobial unless haematogenous spread

 

Ix

- Cultures

-  BC

-  Positive in 50%+/-

-  Most useful in suspected haematogenous spread

-  Wound swab MCS

-  Prior to Abx

- FBE: elevated WBC

- CRP +/- ESR

- +/- Bone Bx

-  Gold standard = bone Bx w MCS + Histo: inflammation + osteonecrosis

-  Percutaneous or open

- X-ray

-  1st line imaging

-  Sequestra

-  Involucrum

- +/- Bone Scan

-  More suitable in metal in situ

- +/- MRI

 

Mx

-  Surgical or Medical (long term Abx)

-  Empirial Antibiotics

-  After cultures

-  Di/Flucloxacillin 2g (kids 50mg/kg) IV 6/24

-  If sens to Penicillins use Cephazolin 2g (50mg/kg) IV 8/24

-  If Penicillin anaphylaxis use Vancomycin 1.5g (kids 30mg/kg) IV 12/24 then dose adjust

-  Directed Antibiotics

-  Based on MCS/BC

-  Usually IV for 6 weeks duration (via PICC +/- HITH)

-  Neonates min 4 weeks IV

-  Kids (acute) 3/7 min IV, min 4 weeks total

-  Kids (chronic) +/- IV, months+/- total

-  Adult (acute) min 4 weeks IV, min 6 weeks total

-  Adult (chronic) min 2 weeks IV, months+/- total

-  MSSA (Staph)

-  Di/Flucloxacillin 2g (kids 50mg/kg) IV 6/24

-  If sens to Penicillins use Cephazolin 2g (50mg/kg) IV 8/24

-  If Penicillin anaphylaxis use

-   Clindamycin 450mg (kids 10mg/kg) IV 8/24

-   OR Lincomycin 600mg (kids 15mg/kg) IV 8/24

-  MRSA

-  Vancomycin 1.5g (kids 30mg/kg) IV 12/24 then dose adjust

-  Gram –ves

-  Cefotaxime 2g (kids 50mg/kg) IV 8/24

-  OR Ceftriaxone 2g (kids 50mg/kg) IV Daily

-  Surgery

-  Debridement

-  Amputation

-  Removal of prosthesies

-  +/- revascularisation

-  +/- Hyperbaric O2

-  +/- VAC dressings as relevant

 

 

 

References

 

eTG: Osteomyelitis

UpToDate: Overview of Osteomyelitis in Adults: 14/01/2011