Dr. Puligandla -- Soft Tissue Infections Flashcards
Common and primary goal of surgical team
Prevention of surgical site infections in the OR
Goal of anti-sepsis
Prevent the contamination of the open surgical wound by isolating the operative site from the surrounding non-sterile environment
7 uncomplicated soft tissue infections
- Cellulitis
- Erysipelas
- Abscess
- Folliculitis
- Furunculosis
- Impetigo
- Ecthyma
9 complicated soft tissue infections
- Traumatic wound infectoin
- Bite-related wound infection
- Postop wound infection
- Secondary infectio nof a diseased skin (i.e. eczema)
- Diabetic foot infection
- Vanous stasis ulcer/ infected pressure sores
- Perianal skin infection
- Necrotizing infection
- Myonecrosis
Layers of skin involved in cellulitis
- Epidermis
- Dermis
3 organisms responsible for cellulitis
- S. pyogenes
- S. aureus
- H. influenzae
3 symptoms of cellulitis
- Pain
- Erythema
- Swelling
2 treatments for cellulitis
- Antibiotics
- Incision and drainage (I+D)
Define erysipelas
Superficial infection of skin that spreads rapidly and involved dermal lymphatics
Cause of erysipelas
GAS
4 symptoms of erysipelas
- Fever
- Pain
- “Aches”
- Adenitis
Usual location of erysipelas
Legs > face
Erysipelas treatment
Penicillin G
Skin layers involved in skin abscess
- Epidermis
- Dermis
- Occasionally deeper structures
Usual cause of skin abscess
S. aureus
Treatment for skin abscess
I+D; antibiotics reseved for those with an associated cellulitis
4 antibiotics for mild cellulitis
- TMP/SMX DS (160/800 mg) 1 - 2 tablets bid plus cephalexin 500 mg qid
- Clindamycin 300 mg qid
- Minocycline 100 mg bid (first dose 200 mg)
- Doxycycline 100 mg bid
Define felon
Hand infection wherein distal pulp space of finer is compartmentalized by fibrous septa and infection arises from direct innoculation wtih bacteria (puncture wound; less commonly hematogenous spread)
Clinical manifestation of felon
Intensely painful throbbing pulp space
Potential complciation of felon
Pressure can lead to necrosis with spread to tendons, ligaments and bone
Treatment for felon
- I+D
- Antibiotics against common strep and staph species
Define paronychia
Infection of skin over the mantle of the nail or of the lateral nail fold
Clinical manifestation and potential complication of paronychia
Swollen, tender, with progression to felon is untreated
Treatment for paronychia
- I+D
- +/- removal of the nail
Define tenosynovitis
Hund infection due to a penetrating injury to volar surface involving tendom sheath
4 Kanavel’s signs
- Finger held in mild flexion
- Fusiform swelling
- Tender along tendon sheath
- Pain with passive extension
4 complications of tenosynovitis
- Tendon necrosis
- Tendon sheath disruption
- Contracture
- Proximal extension
Treatment for tenosynovitis
- Antibiotics
- Surgical debridement
Organisms that can lead to infection due to a human bite
Aerobic and anaerobic
Treatment for human bite
- Antibiotics
- Possible debridement
- DO NOT close punture site due to high risk of infection
3 antibiotics for outpatient therapy for dog, cat and human bites
- Amoxicillin/clavulanate 875/125 mg bid
- Moxifloxacin 400 mg daily
- Clindamycin 300 mg qid plus Ciprofloxacin 500 mg bid
2 antibiotics for dog, cat, and human bite inpatient parenteral therapy
- Ampicillin/sulbactam 1.5 g - 3 g IV q 6 h
- Moxifloxacin 400 mg IV qd
Define diabetic foot
Glove and stocking neuropathy with compromised vascular supply +/- microvascular disease
Progression of diabetic foot
Cellulitis to chronic osteomyelitis
Why is diabetic foot difficult to treat?
Poor microcirculation
Treatment for diabetic foot
- Antibiotics, debridement +/- amputation
- Revascularization
3 organisms responsible for diabetic foot infection
- GAS
- S. aureus
- Pseudomonas (deep)
Inpatient parenteral antibiotics for moderate-to-severe cellulitis or abscess (2)
- Clindamycin 600 mg - 900 mg IV q 8 h
- Monotherapy only for moderate
- Vancomycin 1 g IV q 12 h +/- cefazolin 1 g IV q 6 h
- May replace cefazolin with nafcillin or oxacillin 1 g-2 g every 4 h
- Addition of beta-lactam may provide enhanced activity against MSSA or strep (pref. if S. aureus)
2 outpatient antibiotic therapies for diabetic foot infection
- Clindamycin 300 mg qid plus Ciprofloxacin 500 mg bid
- Amoxicillin/clavulanate 875/125 mg bid +/- TMP/SMX DS (160/800 mg) 1 - 2 tablets bid
3 inpatient parenteral antibiotics for diabetic foot infection
- Ceftriaxone 1 g IV q 24 h + metronidazole 500 mg IV q 6 - 8 h +/- Vancomycin 1 g IV q 12 h
- Ertapenem 1 g IV q 24 h +/- vancomycin 1 g IV q 12 h
- Tigecycline 50 mg IV q 12 h (first dose 100 mg IV)
4 necrotizing infections
- Clostridial infections
- Necrotizing fasciitis
- Bacterial synergistic gangrene
- Streptococcal gangrene
Bacteriology of NI’s (5 organisms)
- Rarely single organism (except GAS)
- B-hemolytic strep
- Anaerobic GPC
- Aerobic GNR
- Bacteroides
- NOTE: Synergy between aerobic and anaerobic organisms for the necrosis of skin, soft tissue and fascia
How to diagnose NI’s (6)
- Often lack any diagnostic external signs of necrotizing infection (maybe cellulitis or small ulcer)
- Gold standard = tissue biopsy (frozen section, gram stain)
- Plain radiographs
- CT scan
- MRI
- Surgical debridement
Most frequent spontaneous site of NI
Perineum
Most frequent site overall for NI
Limbs (due to wound, puncture, injury)
7 predisposing events that put one at risk for NI
- Minor trauma
- Insect bites
- IVDU
- Drug reactions
- Perirectal abscesses
- Major trauma
- Surgical procedures
8 associated conditions to NI
- DM
- Cancer
- Immune suppression
- Renal insufficiency
- Older age
- Malnutrition
- Obesity
- Arteriosclerosis
Define bacterial synergistic gangrene
- Rare form of gangrene affecting trunk and limbs (Meleney’s ulcer).
- Slow infection affecting skin and soft tissues but not fascia
3 organisms responsible for bacterial synergistic gangrene
- Streptococci
- S. aureus
- GNR
Treatment for bacterial synergistic gangrene
- Antibiotics
- Radical debridement
Define necrotizing fasciitis
Aggressive necrotizing infection involving the skin, soft tissue and fascia but not the muscle
3 symptoms associated with necrotizing fasciitis
- Hypotension
- Fever
- Decreased level of consciousness
3 supportive treatments for necrotizing fasciitis
- Resuscitation
- Antibiotics
- IVIG
3 surgical treatments for necrotizing fasciitis
- Fascial probing
- Radical debridement
- Reconstruction
6 extracellular products of GAS capable of tissue destruction
- Erythrogenic toxins A, B, and C
- Streptolysins O and S
- Streptokinases A and B
- Ribo and deoxyribonucleases
- Hyaluronidases, proteinases
- Exotoxin A “superantigens”
3 supportive therapies for GAS infection
- Mechanical ventilation
- Fluid resuscitation
- Inotropic medication for hypotension
Antibiotic therapy for GAS infection
Penicillin
Surgical management of GAS infection
Wide surgical debridement to normal tissue –> amputation
Define clostridial cellulitis
Slow progressive infection of the soft tissues sparing the muscle
Clinical manifestation of clostridial cellulitis
- Crepitus (gas) in subcutaneous tissues
- Foul-smelling exudate
2 organisms responsible for clostridial cellulitis
- C. perfringes
- C. sporogenes
Treatment for clostridial cellulitis
- Wide debridement
- Broad spectrum antibiotics (penicillin-based)
Define clostridial myonecrosis
Rapidly progressive infection involving dermis, fascia and muscle but sparing epidermis (no inflammation)
Clinical manifestation of clostridial myonecrosis
- “Mousy smell”
- Bronzing of skin
Treatment for clostridial myonecrosis
- Rapid debridement often requiring amputation
- Penicillin G = mainstay of treatment
2 antimicrobial treatment regimens for necrotizing soft tissue infections
- Vancomycin 1 g IV q 1 h + Clindamycin 900 mg IV q 8 h + Pip/tazo 3.375 g IV q 6 h
- Can replace vancomysin with daptomycin
- Can replace pip/tazo with imipenem or meropenem
- Linezolid 600 mg IV q 12 h + pip/tazo 3.375 g IV q 6 h
9 uses for hyperbaric oxygen treatment
- Chronic non-healing wounds
- Osteomyelitis (bone infections)
- Thermal burns
- CO poisoning
- Smoke inhalation
- Industrial accidents/crush injuries
- Necrotizing fasciitis
- Gas gangrene
- Decompression sickness/diving accidents
