Diabetic Foot Infection (DFI) management
Principles
DFI management ต้อง multidisciplinary:
- wound
care
- infectious
disease
- surgery
- endocrinology
- vascular
team
Main components
1.
ประเมิน severity
2.
ประเมิน need for
surgery/revascularization
3.
Appropriate antibiotics
4.
Wound care + offloading
5.
Glycemic control
6.
Manage PAD/neuropathy/edema
Admission Criteria
Admit ถ้ามี
Severe infection / sepsis
- systemic
toxicity
- hemodynamic
instability
Limb-threatening findings
- rapidly
progressive erythema
- necrosis
- crepitus
- gas
on imaging
- deep
abscess
- severe
ischemia
- necrotizing
infection
Other indications
- unable
to do wound care/offloading
- need
IV antibiotics
- urgent
surgery/vascular evaluation needed
Important pearl
Osteomyelitis อย่างเดียว ≠ automatic admission
Uninfected Ulcer
ห้ามให้ antibiotics
แม้ culture positive
เพราะ:
- ulcer
almost always colonized
- ไม่ช่วย prevent infection
- เพิ่ม resistance/adverse effects
Role of Surgery
Goals
- remove
necrotic tissue
- drain
abscess
- reduce
bacterial burden
- obtain
deep culture
Urgent surgical indications
- deep
abscess
- extensive
bone/joint involvement
- necrosis/gangrene
- necrotizing
fasciitis
- compartment
syndrome
- severe
ischemia
PAD pearl
ควร vascular evaluation ก่อน
surgery ถ้าสงสัย ischemia
อาจต้อง:
- angioplasty
- bypass
ก่อน debridement
Early Surgery
สำคัญมาก
delay surgery >72 hr ใน severe
infection
→ amputation risk สูงขึ้น
Surgical Technique
Preferred method
sharp debridement
- scalpel
- scissors
Why?
antibiotics penetrate necrotic tissue poorly
Wound Culture
Correct specimen
- deep
tissue
- abscess
aspirate
- curettage
from ulcer base after debridement
Wrong specimen
❌ superficial swab
เพราะ unreliable
Antibiotic Principles
เลือกตาม:
- severity
- MRSA
risk
- Pseudomonas
risk
- anaerobic
risk
Anaerobic Coverage
Indications
- necrosis
- gangrene
- foul
odor
- gas
on imaging
- severe
ischemia
MRSA Coverage
Consider when
- severe
infection
- prior
MRSA
- known
colonization
- high
local prevalence
Pseudomonas Coverage
ไม่ต้อง cover routine ทุก
case
Consider when
- warm/tropical
climate
- water
exposure
- moist
macerated ulcer
- prior
deep culture positive
Pearl
superficial swab positive for Pseudomonas
≠
true indication to cover
Mild Infection Treatment
Outpatient oral therapy
Target
- Streptococci
- MSSA
No MRSA risk
Options
- Dicloxacillin
- Cephalexin
- Cefadroxil
MRSA risk
Options
- TMP-SMX
- Doxycycline
+ amoxicillin
Moderate Infection
Coverage
- streptococci
- S.
aureus
- gram
negative bacilli
- ±
MRSA
- ±
Pseudomonas
- ±
anaerobes
Example regimens
No MRSA/Pseudomonas risk
- Amoxicillin-clavulanate
MRSA risk
- Augmentin
+ doxycycline/TMP-SMX
Pseudomonas risk
- Augmentin
+ ciprofloxacin
MRSA + Pseudomonas risk
- Levofloxacin
+ doxycycline/TMP-SMX
- metronidazole
if anaerobic risk
Severe Infection
Management
- broad-spectrum
IV antibiotics
- urgent
surgery often needed
Must cover
- Streptococci
- MRSA
- gram
negative incl. Pseudomonas
- anaerobes
Example regimen
- Vancomycin
+ piperacillin/tazobactam
or
- Vancomycin
+ cefepime + metronidazole
Duration: Soft Tissue Infection
Typical duration
- mild
infection → 1–2 weeks
- moderate/severe
→ up to 4 weeks
After complete surgical resection
- <5
days often sufficient
Causes of Treatment Failure
อย่าคิดว่า antibiotic failure เสมอไป
Common causes
- undrained
abscess
- residual
necrotic tissue
- poor
wound care
- severe
PAD
- edema
- inadequate
offloading
Osteomyelitis Management
Main components
- surgery
- antibiotics
- wound
care
Surgery in Osteomyelitis
Surgical options
- debridement
- bone
resection
- amputation
Goal
preserve biomechanics ให้มากที่สุด
จึงมัก prefer:
- debridement
- partial
amputation
มากกว่า major amputation
When Can Osteomyelitis Be Treated Without Surgery?
Consider antibiotics alone if ALL:
- forefoot
osteomyelitis
- no
soft tissue debridement needed
- no
significant PAD
- no
exposed bone
Antibiotic Route
IV therapy indications
- severe
infection
- limb-threatening
infection
- extensive
necrotic tissue
- no
reliable oral option
- malabsorption
- severe
ischemia/edema
Oral Therapy for Osteomyelitis
Increasing evidence supports oral therapy
Suitable if
- clinically
stable
- no
severe infection
- minimal
necrotic tissue
- highly
bioavailable drug available
- can
absorb/take medication reliably
Common oral regimens
- Amoxicillin-clavulanate
- Levofloxacin
± metronidazole
- Moxifloxacin
- TMP-SMX
± metronidazole
Osteomyelitis Duration
Residual infected bone remains
→
usually 6 weeks
Complete resection/amputation with no residual infection
→
antibiotics may not be needed
or ≤5
days
Follow-up
Osteomyelitis relapse
อาจเกิดหลัง apparent cure หลายเดือน
Many experts:
consider “cured”
หลังหยุด antibiotics 6–12 months
Follow-up imaging
ไม่ routine
ยกเว้นสงสัย progression
Wound Management
Critical components
- offloading
- intermittent
debridement
- dressing
care
- pressure
reduction
Adjunctive Therapies
Most commonly used
- vacuum-assisted
wound closure (VAC)
Generally NOT recommended routinely
- hyperbaric
oxygen
- topical
antibiotics
- silver/honey
- G-CSF
Prevention
Prevention strategy
- regular
foot exam
- proper
footwear
- ulcer
care
- vascular
management
- glycemic
control
No prophylactic antibiotics
for colonized/uninfected ulcers
High-Yield Clinical Pearls
Necrotic tissue must be removed
antibiotics alone often fail
Superficial swab culture is misleading
deep tissue specimen only
Pseudomonas coverage ไม่จำเป็น routine
Stable forefoot osteomyelitis
บางรายรักษาด้วย oral antibiotics only ได้
Complete infected bone resection
→
prolonged antibiotics often unnecessary
Most treatment failure
เกิดจาก:
- poor
vascular supply
- residual
abscess/necrosis
- poor
offloading
ไม่ใช่ antibiotic spectrum อย่างเดียว
