DFI and Pressure Ulcers

Question 1

What is Diabetic Foot Infection?

Answer 1

Soft tissue or bone infection below the malleolus

Areas of DFI:
- skin ulceration (peripheral neuropathy)
- wound (trauma)

Complications:
- hospitalization
- osteomyelitis => amputation

Question 2

What is the pathophysiology of DFI?

Answer 2

1. Neuropathy
   - Peripheral: decrease pain sensation and altered pain response
   - Motor: muscle imbalance
   - Autonomic: increase dryness, cracks, and fissures
2. Vasculopathy
   - Early atherosclerosis
   - Peripheral vascular disease
   - Worsened by hyperglycemia and hyperlipidemia
3. Immunopathy
   - Impaired immune response
   - Increase susceptibility to infections
   - Worsened by hyperglycemia

=> Ulcer formation and wounds
=> Bacterial colonization, penetration and proliferation
=> DFI

Question 3

Definition of DFI (INFECTED)

Answer 3

Purulent discharge

OR

> = 2 signs or symptoms of inflammation (PWETI)
- Erythema
- Warmth
- Tenderness
- Pain
- Induration (hardness)

Question 4

What are the causative organisms of DFI?
*Typically polymicrobial

Answer 4

Staphyloccous Aureus

Streptococcus

Gram-negative bacilli - Particularly in chronic wounds or previously treated with antibiotics
- E. coli, Klebsiella, Proteus
- Pseudomonas (less common)

Anaerobes - ischemic or necrotic wounds
- Peptostreptococcus, Veillonella, Bacteroides

Question 5

When should culture be obtained for DFI?

Answer 5

Mild DFI - optional

Moderate-severe DFI - deep tissue cultures after cleansing and before starting antibiotics (if possible), avoid skin swabs

*Do not culture uninfected wounds

Question 6

DFI treatment is dependent on _____ and ______

Answer 6

Severity of infection

• based on IDSA (mild, moderate, severe definition)
• account for SIRS criteria (systemic signs)
• account for extent of tissue involvement

AND

Patient specific factors

• allergies
• MRSA risk factors
• pseudomonal risk factors (water exposure, warm climate)

Question 7

When should Pseudomonas cover be considered in DFI?

Answer 7

*Pseudomonas should be covered when:
- severe infection
- failure of antibiotics not active against pseudomonas

Question 8

What constitutes a MILD IDSA Infection Severity (DFI)

Answer 8

Mild
- Infection of skin and sc tissue +
- If erythema =<2cm around ulcer +
- No signs of systemic infection

Question 9

What organisms should be covered in MILD DFI?

Answer 9

Staph
Strep

Question 10

What are the empiric antibiotic options for MILD DFI?

Answer 10

PO Cephalexin 500mg q6h
PO Cloxacillin 500mg-1g q6h
PO Clindamycin 300-450mg q6h (penicillin allergy)

Question 11

What are the empiric antibiotic options for MILD DFI?
(If there are MRSA risk factors, use what instead?)

Answer 11

If MRSA risk factors
- PO Cotrimoxazole 960mg bid
- PO Clindamycin 300-450mg q6h
- PO Doxycyline 100mg bid

Question 12

What is the duration of therapy for MILD DFI?

Answer 12

1-2 weeks

Question 13

What constitutes a MODERATE IDSA Infection Severity (DFI)?

Answer 13

Moderate
- Infection of deeper tissue (e.g., joints, bones)
or
- If erythema >2cm +
- No signs of systemic infection

Question 14

What organisms should be covered in MODERATE DFI?

Answer 14

Staph
Strep
Gram-negative
Anaerobic

Question 15

What are the empiric antibiotic options for MODERATE DFI?

Answer 15

IV Amoxicillin-Clavulanate 1.2g q6-8h
IV Cefazolin 1-2g q8h + Metronidazole 500mg q8h
IV Ceftriaxone 1-2g q12-24h + Metronidazole 500mg q8h

Question 16

What are the empiric antibiotic options for MODERATE DFI?
(What to ADD if there are MRSA risk factors)

Answer 16

If MRSA risk factors: add
- IV Vancomycin 15mg/kg q8-12h
- IV Daptomycin 4-6mg/kg q24h
- IV Linezolid 600mg q12h

*Reserve Daptomycin and Linezolid for vancomycin resistance, more ex as well

Question 17

What is the duration of therapy for MODERATE DFI (no bone involvement)?

Answer 17

1-3 weeks

Question 18

What constitutes a SEVERE IDSA Infection Severity (DFI)?

Answer 18

Moderate
- Infection of deeper tissue (e.g., joints, bones)
or
- If erythema >2cm +
- Signs of systemic infection

Question 19

What organisms should be covered in SEVERE DFI?

Answer 19

Staph
Strep
Gram negative
Anaerobe
Pseudomonas

Question 20

What are the empiric antibiotic options for SEVERE DFI?

Answer 20

IV Piperacillin-Tazobactam 4.5g q6-8h
IV Cefepime 2g q8h + Metronidazole 500mg q8h
IV Meropenem 1-2g q8h
IV Ciprofloxacin 400mg q8-12h + Clindamycin 600mg q8h
IV Ceftazidime 1-2g q8h + Clindamycin 600mg q8h

Question 21

What are the empiric antibiotic options for SEVERE DFI?
(What to ADD if there are MRSA risk factors)

Answer 21

If MRSA risk factors add:
IV Vancomycin 15mg/kg q8-12h
IV Daptomycin 4-6mg/kg q24h
IV Linezolid 600mg q12h

Question 22

What is the duration of therapy for SEVERE DFI (no bone involvement)?

Answer 22

2-4 weeks

Question 23

What is the duration of therapy for DFI with bone involvement?

Surgery - all infected bone and tissue removed

Answer 23

Surgery - all infected bone and tissue removed (e.g., amputation): 2-5 days

Question 24

What is the duration of therapy for DFI with bone involvement?

Surgery - residual infected soft tissue

Answer 24

Surgery - residual infected soft tissue: 1-3 weeks

Question 25

What is the duration of therapy for DFI with bone involvement? Surgery - residual viable bone

Answer 25

Surgery - residual viable bone: 4-6 weeks

Question 26

What is the duration of therapy for DFI with bone involvement? No surgery or Surgery - residual dead bone

Answer 26

No surgery or Surgery - residual dead bone: >= 3months

Question 27

When should antibiotics for DFI be stopped/changed?

Answer 27

Do not continue Abx until complete wound healing (bacteria cleared faster than wound heals) Streamline choice of Abx based on culture and AST (impt as the empiric choices are broad spectrum => selection pressure) Switch to oral therapy when patient improved

Question 28

What are the adjunctive measures for DFI?

Answer 28

Wound care - debridement - "off-loading" - relieve pressure on ulcer - apply dressings that promote a healing environment and control excess exudation Foot care - daily inspection - prevent wounds and ulcers Optimal glycemic control

Question 29

What are Pressure Ulcers?

Answer 29

Pressure ulcers = Decubitus ulcers = Bed sores Synergistic interaction between 4 factors: Moisture Pressure (amount of time and duration) Shearing force Friction

Question 30

What are the risk factors for Pressure Ulcers?

Answer 30

Reduced mobility Debilitated by severe chronic diseases Reduced consciousness Sensory and autonomic impairment - incontinence (moisture) Extremes of age - mobility issue Malnutrition

Question 31

What are the 4 stages of clinical presentation of Pressure Ulcers?

Answer 31

Stage 1: abrasion of epidermis, irregular area of tissue swelling, no open wound Stage 2: extends through dermis, open wound Stage 3: extends deep into s/c fat, open sore or ulcer Stage 4: involves muscle and bone, deep sore or ulcer *Similar criteria for INFECTION applies: - Purulent OR - >= 2 signs and symptoms of inflammation: erythema, warmth, tenderness, pain, induration

Question 32

What are the causative organisms of Pressure Ulcers?

Answer 32

Identical to DFIs, polymicrobial Staphyloccous Aureus Streptococcus Gram-negative bacilli - Particularly in chronic wounds or previously treated with antibiotics - E. coli, Klebsiella, Proteus - Pseudomonas (less common) Anaerobes - ischemic or necrotic wounds - Peptostreptococcus, Veillonella, Bacteroides

Question 33

Treatment of Pressure Ulcers?

Answer 33

same as DFI

Question 34

What are the adjunctive measures for Pressure Ulcers?

Answer 34

Wound care - debridement of infected or necrotic tissue - local wound care: normal saline, avoid harsh chemicals Relief of pressure - turn/reposition every 2h Barrier creams/dressings