diabetic foot infection Flashcards
areas of DFI
- skin ulceration (peripheral neuropathy)
- wound (trauma)
complications of DFI
- hospitalisation
- osteomyelitis -> amputation
pathophysiology of DFI
neuropathy + vasculopathy + immunopathy -> ulcer formation/wound -> bacterial colonisation, penetration, proliferation -> DFI
DFI patho: neuropathy causes
1) peripheral: decreased pain sensation & altered pain response
2) motor: muscle imbalance
3) autonomic: increase dryness, cracks, fissures
DFI patho: vasculopathy causes
1) early atherosclerosis
2) peripheral vascular disease
3) worsen by hyperglycaemia & hyperlipidaemia
DFI patho: immunopathy causes
1) impaired immune response
2) increased susceptibility to infection
3) worsen by DM
progression of DFI
superficial ulcer, mild erythema -> deep tissue infection, extensive erythema -> infection of bone & fascia, purulent discharge
evolution of DFI by days
day 1: erythema
day 3: blisters
day 6: necrotising tissue
day 10: wound infection requiring surgery
causative organisms for DFI
(usually polymicrobial)
1) staph aureus, streptococcus spp
2) gram neg bacilli
- usually wet wound
- esp in chronic wound/prev treated w Abx
- E. coli, klebsiella spp, proteus spp
3) anaerobes
- ischaemic/necrotic wound
- peptostreptococcus spp, veillonella spp, bacteroides spp
severity of DFI vs need for culture
1) mild: optional
2) moderate - severe
- deep tissue culture after cleansing
- X culture uninfected wounds
definition of mild DFI
- infection of skin & SC tissue
- erythema ≤ 2 cm around ulcer
- X signs of systemic
organisms to cover for mild DFI
- streptococcus spp, S. aureus
Abx for mild DFI
1) normal PO Abx
- cephalexin, cloxacillin, clindamycin
2) PO Abx if MRSA risk factors
- cotrimoxazole, clindamycin, doxycycline
definition of moderate DFI
- infection of deeper tissue (bone, joint)
- erythema > 2 cm around ulcer
- X signs of systemic
organisms to cover for moderate DFI
streptococcus spp, S. aureus, gram neg (+/- pseudomonas), anaerobes
Abx to use for moderate DFI
1) initial IV Abx
- augmentin, cefazolin/ceftriaxone + metronidazole
2) MRSA risk factors add IV
- vanco/dapto/linezolid
definition for severe DFI
- infection of deeper tissue (bone, joint)
- erythema > 2 cm around ulcer
- signs systemic infection
organisms to cover for severe DFI
- streptococcus spp, S. aureus, gram -ve (include pseudomonas), anaerobes
Abx to use for severe DFI
1) initial IV Abx
- piper/tazo, meropenem
2) MRSA risk factors add IV
- vanco/dapto/linezolid
duration of DFI therapy based on severity
1) X bone involved
- mild: 1-2 wks
- moderate: 1-3 wks
- severe: 2-4 wks
2) bone involved
- amputation: remove all infected bone & tissue: 2-5 days
- residual infected soft tissue: 1-3 wks
- residual viable bone: 4-6 wks
- X surgery/residual dead bone: ≥ 3 months
adjunctive measures for DFI
1) wound care
- debridement
- offloading
- apply dressing that promote healing env & control excess exudation
2) foot care
- daily inspection
- prevent wound & ulcer
3) optimal glycaemic control
