8 - Surgical Management of Foot Infection Flashcards
Objectives
- Evaluation and management of foot infections requiring surgical treatment.
- Current IDSA guidelines for diabetic foot infections.
Indications for surgical interventions
- Abscess
- Osteomyelitis
- Gas Producing infection = Medical emergency
Good info to get in the history
o Speed of onset and duration
o Trauma
o Sources of contamination of wound
o Pain – particularly in insensate person
o If likely surgical case, when person last ate or drank
Good info to get in the ROS
o F/C/N/V
o Recent blood glucose
Review drug allergies
Physical exam
o Palpable fluctuance, or crepitance
o Lymphangitic streaking
o Mark leading edge of erythema
o Vitals
X-rays
o Look for gas, foreign bodies, signs of osteomyelitis
Labs to get
o WBC, CMP
o ESR or CRP
IDSA (infectious disease society of America) Diabetic Foot Infection Classification
- Uninfected
- Mild
- Moderate
- Severe
Uninfected
o Wound without purulence or any manifestations of inflammation
Mild
o Cellulitis or erythema > 0.5cm to ≤2 cm around ulcer or wound
o Infection is limited to skin or superficial subcutaneous tissue
o No local complications or systemic illness
o ***Should exclude other causes of inflammation (e.g., trauma, gout, acute Charcot, fracture, thrombosis, venous stasis)
Moderate
o Erythema >2 cm, OR involving deeper structures than skin or subcutaneous tissue (e.g. abscess, osteomyelitis, septic arthritis, fasciitis)
o AND no systemic inflammatory response syndrome (SIRS)
Severe
Local infection (as described previously) with signs of SIRS as manifested by ≥2 of the following:
- Temperature > 38°C or 90 beats/min
- Respiratory rate >20 breaths/min or PaCO2 12,000 or
IDSA validation - full thickness
This is how often each grade of the IDSA scale leads to a full thickness wound (no deeper):
- No infection: 88.7%
- Mild infection: 76.1%
- Moderate infection: 30.8%
- Severe infection: 22.2%
IDSA validation - fascia or tendon
This is how often each grade of the IDSA scale probes to fascia or tendon (no deeper)
- No infection: 7.2%
- Mild infection: 21.1%
- Moderate infection: 25.0%
- Severe infection: 11.1%
IDSA validation - bone or joint
This is how often each grade of the IDSA scale probes to bone or joint:
- No infection: 4.1%
- Mild infection: 2.8%
- Moderate infection: 44.2%
- Severe infection: 66.7%
IDSA validation - bone infection
This is how often each grade of the IDSA sale leads to bone infection
- No infection: 0%
- Mild infection: 0%
- Moderate infection: 38.5%
- Severe infection: 37%
Graph on hospitalization and amputation rates based on the IDSA grade of infection
- No infection: very few hospitalizations, very few amputations
- Mild infection: 10% are hospitalized, very few amputations
- Moderate infection: 55% are hospitalized, 45% have amputations
- Severe infection: 90% are hospitalized, 75% have amputations
Causative organism for cellulitis without open skin lesion
- Staph aureus
- Beta hemolytic strep
Causative organism for infected ulcer, antibiotically naive
- Staph aureus
- Beta hemolytic strep
Causative organism for infected ulcer, previously treated
- Staph aureus
- Beta hemolytic strep
- Enterobacter
Causative organism for macerated ulcer due to drainage or soaking
- Pseudomonas
- Polymycrobial
Causative organism for long standing ulcer with prolonged broad spectrum antibiotic use
- Polymycrobial
- Staph aureus
- Beta hemolytic
- Pseudomonas
- Gram negative rods
- Resistant bacteria
Causative organism for “fetid foot” - extensive necrosis or gangrene
- Gram positive cocci
- Gram negative rods
- Obligate anerobes
Causative organism for osteomyelitis
- Staph aureus
- Pseudomonas (puncture wounds)
Clinical signs of MSSA
o Thick, yellow, purulent drainage
Clinical signs of MRSA
o Usually quicker onset of purulent producing infection
Clinical signs of Strep
o Deeper red infection than staph and not as purulent
Clinical signs of pseudomonas
o Fruity smell
o Green tinge to wound
Clinical signs of anaerobes
o Extreme foul smell
o Brown, watery discharge
IDSA suggested antibiotics for moderate to severe foot infections with MSSA, streptococcus, enterobacteria and obligate anaerobes
1 = Ampicillin-sulbactam (Unasyn)
- This is adequate if low suspicion of pseudomonas
2 = Ertapenem
- Once daily dosing, relatively broad spectrum, not active against pseudomonas
3 = Imipenem-cislastin
- Very broad spectrum (no MRSA coverage) only use when needed
IDSA suggested antibiotics for moderate to severe foot infections with MRSA
Vancomycin
IDSA suggested antibiotics for moderate to severe foot infections with pseudomonas aeruginosa
Piperacillin-tazobactam (zosyn)
- TID or QID dosing, but good broad spectrum coverage
Case study HPI
o 53 year old female admitted to hospital by PCP for diabetic foot infection
o PCP noted larger bulla on plantar right midfoot with foul drainage
o Pain on foot and leg
o Fever (102 degrees F), chills, nausea, vomiting
Case study ROS
o Last blood glucose 200-300 o A1c 8-10 o Numbness in hands and feet o Blurred vision secondary to retinopathy o Heart palpitations for 2 days
Case study PMHx
o Type 2 diabetes
o Renal failure with dialysis
Case study physical exam
o Vascular: pedal pulses palpable o Neuro: diminished o Foot: hot, swollen, erythematous foot o Derm: large bulla the width of the plantar arch with gray/black in color with small opening centrally. Erythema to surrounding tissue, no purulent drainage o Musculoskeletal: pain with palpation
X-ray
o Gas gangrene in the medial arch
o Make sure it isn’t tracking up into the leg (this stays mostly in the arch, medial to lateral)
Culture
o Either culture drainage in the ER or do it in the OR
Labs yesterday and labs today
- Labs yesterday (CRP, ESR, WBCs) o WBC = 29.5 (10 is normal) o H/H = 10.6/31 o Bun/Cr = 86/6.2 o Blood glucose = 294 o Albumin = 3.2 o C-reactive protein = 24.1 (1 or less is normal)
Treatment
Emergency I & D
o Infections will more commonly track up tendons
o Less commonly it will track across the arch
o Can see the plantar fascia
o Use bag of 300 mL of saline and wash it out with pressure lavage
Dressing
o Pack the wound
o Do not close the wound because it would increase an anaerobic environment
o Let it drain then go back a few days later
Cultures
o Staph aureus o Strep (GBS) o Bacteroides o MRSA o Enterobacter
Repeat I & D
o Back to OR for repeat
o Continued purulent drainage
o Intraoperative findings = necrotic tissue found within wound
o Purulent drainage from multiple deep pockets
o Wound VAC applied in OR
Management going forward
o Diabetes
o Living situation with help
o WB, antibiotics
Discharge from hospital
o Patient sent to SNF for wound vac therapy and 4 weeks IV abx (vanc, zosyn) per ID recommendation
o Wound eventually healed
CASE STUDY 2
o 51 year old male presents to clinic with ulcer plantar left hallux
o Went on fishing trip 1 month ago, ulcer formed from wet, rubbing boots
o 10 days ago noticed erythema and edema
o 4 days ago went to ED and was put on ED
Case study PMHx
o T2D, HTN
o Heart murmur
o High cholesterol, colon cancer hx
Case study social
o Denies tobacco, alcohol, drug use
o Counselor at prison system
Case study ROS
o Denies fever, chills, nausea, vomiting
o Blood glucose around 120, does not check often due to
o Some numbness and tingling in the feet
o Does not feel like feet are hot or cold (vascular)
o Denies claudication
o Had ulcers before? Did they heal?
Case study physical exam
o Pedal hair present
o Pedal pulses are not palpable but are biphasic with Doppler and pedal hair is present
o Cannot feel monofilament (2/10)
o Size of ulcer is 2 mm in diameter
o Derm: erythema noted to lef hallux with slight purpule discoloration
o Ulcer plantar hallux IPJ with yellow fibrotic base
o Edema present to hallux and foot
o Musculoskeletal: ROM is somewhat limitied to 1st MPJ, pain to palpation of the hallux, no fluctuance or crepitus
Case study initial visit
o Purple discoloration from infection
o Get x-ray, take culture, get bloodwork
o Antibiotics are not currently helping
o Vascular studies (did not get them because circulation was pretty good)
o Offloading (total contact cast, boot, post-op shoe, cutout over 1st ray)
o Dress the wound, does not meet criteria to put in the hospital
Cultures
o Group G strep
o MSSA
Bactrim
o Bactrim only covers staph and usually MRSA
o Bactrim does NOT cover strep very well – not great
X-rays
o No gas present
o No erosive changes in bones (no osteo)
1 week later
o Toe started turning gray 2 days after being seen
o Presents with completely black toe
o Needs amputation right away
o Progressed so quickly so be suspicious of necrotizing fasciitis
Hospital
o Admit to hospital
o X-rays
o Labs
o Amputation
Labs at hospital
o WBC = 12.7
o Sed rate = 100
o CRP = 7.5
o AbA1c = 8.1
Treatment
o Hallux amputation performed
o Cultures came back as skin flora
o Patient send home non-weight bearing
4 weeks post op
o Sutures removed because they were loose
o Minimal drainage
o No pain
o Would like to go back to work
6 weeks post op
o Patient called in stating he can see bone
o Instructed to use betadine and call if redness or signs of systemic
o Wound came open 1-2 weeks after going back to work
How to manage now
o X-rays
o 1st ray amputation or partial first ray amputation
o Admit to hospital
o MRI to see extent of bone involvement (1st met head is destroyed, Edema goes back to base of 1st met head, Infectious disease wanted the whole 1st ray to be gone)
o Biomechanics (If you take off the whole first ray, he will have no attachment for Lis francs TA, more pressure on other metatarsals)
2 weeks later
Healing well at this time
Case study 3
- 52-year-old diabetic male with new ulcer plantar 2nd metatarsal head
- Chills nausea
- Vascular -= DP palpable, PT not, glucose 765
- 2nd ray is already missing
- High BP, high pulse, high respirations
- Admitted to hospital right away
- X-rays – Soft tissue gas
