diabetic foot infection

Question 1

areas of DFI

Answer 1

• skin ulceration (peripheral neuropathy)
• wound (trauma)

Question 2

complications of DFI

Answer 2

• hospitalisation
• osteomyelitis -> amputation

Question 3

pathophysiology of DFI

Answer 3

neuropathy + vasculopathy + immunopathy -> ulcer formation/wound -> bacterial colonisation, penetration, proliferation -> DFI

Question 4

DFI patho: neuropathy causes

Answer 4

1) peripheral: decreased pain sensation & altered pain response
2) motor: muscle imbalance
3) autonomic: increase dryness, cracks, fissures

Question 5

DFI patho: vasculopathy causes

Answer 5

1) early atherosclerosis
2) peripheral vascular disease
3) worsen by hyperglycaemia & hyperlipidaemia

Question 6

DFI patho: immunopathy causes

Answer 6

1) impaired immune response
2) increased susceptibility to infection
3) worsen by DM

Question 7

progression of DFI

Answer 7

superficial ulcer, mild erythema -> deep tissue infection, extensive erythema -> infection of bone & fascia, purulent discharge

Question 8

evolution of DFI by days

Answer 8

day 1: erythema
day 3: blisters
day 6: necrotising tissue
day 10: wound infection requiring surgery

Question 9

causative organisms for DFI

Answer 9

(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

Question 10

severity of DFI vs need for culture

Answer 10

1) mild: optional
2) moderate - severe

• deep tissue culture after cleansing
• X culture uninfected wounds

Question 11

definition of mild DFI

Answer 11

• infection of skin & SC tissue
• erythema ≤ 2 cm around ulcer
• X signs of systemic

Question 12

organisms to cover for mild DFI

Answer 12

• streptococcus spp, S. aureus

Question 13

Abx for mild DFI

Answer 13

1) normal PO Abx

• cephalexin, cloxacillin, clindamycin

2) PO Abx if MRSA risk factors

• cotrimoxazole, clindamycin, doxycycline

Question 14

definition of moderate DFI

Answer 14

• infection of deeper tissue (bone, joint)
• erythema > 2 cm around ulcer
• X signs of systemic

Question 15

organisms to cover for moderate DFI

Answer 15

streptococcus spp, S. aureus, gram neg (+/- pseudomonas), anaerobes

Question 16

Abx to use for moderate DFI

Answer 16

1) initial IV Abx

• augmentin, cefazolin/ceftriaxone + metronidazole

2) MRSA risk factors add IV

• vanco/dapto/linezolid

Question 17

definition for severe DFI

Answer 17

• infection of deeper tissue (bone, joint)
• erythema > 2 cm around ulcer
• signs systemic infection

Question 18

organisms to cover for severe DFI

Answer 18

• streptococcus spp, S. aureus, gram -ve (include pseudomonas), anaerobes

Question 19

Abx to use for severe DFI

Answer 19

1) initial IV Abx

• piper/tazo, meropenem

2) MRSA risk factors add IV

• vanco/dapto/linezolid

Question 20

duration of DFI therapy based on severity

Answer 20

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

Question 21

adjunctive measures for DFI

Answer 21

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