Skin and Soft tissue infections - Glew Flashcards
The hair follicle is the portal of entry for what pathogen?
Staph. aureus
What are the three possibile types of skin and soft tissue infections?
Superficial focal - impetigo
Superficial spreading - cellulitis
Deep necrotizing
What are the lesions that can occur in a superfcial focal skin infection?
Impetigo - staph aureus > beta strep
Folliculitis - staph aureus
Furuncle - staph aureus
Carbuncle - staph aureus
Honey colored crusts are characteristic of what?
They are a superficial local lesion - impetigo from a staph aureus infection
Bullous impetigo is what type of a skin infection and what causes it?
It is a supeficial local lesion from staph aureus
Neonatal scar syndrome can result from staph aureus infection in children
What is folluculitis?
A hair follicle inflammation (area of puss limited to the dermis). This is due to staph aureus which spreads thgouh the hair follicle
What pathogen cuases carbuncles and where on the body do they usually occur?
Carbuncles are a result of staph aureus infection and they usually occur on the neck or in places where skin rubs against each other
What is the therapy for pyoderma
Emperic tx or if MRSA:
- Doxycycline
- Sulfa/Trimethoprim
- Linezolid
MSSA:
- Dicloxacillin
- 1st gen Cephalosporin
- Clindamycin (risk of C. DIff)
What are possible types of superficial spreading infections?
Cellulitits (SQ) - beta hemolytic strep > Staph aureus
Erysipelus (dermis) - Strep pyogenes (Grp A)
Lymphagitis (lymphatics) - Beta hemolytic strep > Staph aureus
Lymphadenitis (lymph node) - Staph aureus > betal hemolytic strep
What are the factors that help in pyoderma local care therapy
- Personal hygiene & contact avoidance
- Launder towel & washcloth after use
- Reduce (eliminate) body shaving
- Avoid tight/binding clothing
- Bactericidal body wash daily Chlorhexidine/Hibiclens® X2 minutes → rinse
What are the predisposing conditions for cellulitis?
Venous/lymphatic insufficiency
Arterial insufficiency
Obesity
CHF
Diabetes Mellitus
Neuropathy
Decubitus ulcers
Trauma
Cellulitis characteristic
Cellulitis has hemorrhagic macules and is caused by Group B beta hemolytic streptococcus
What is erysipelas?
“red skin” - potorongee (an orange color to skin)
This is a superficial spreading condition caused by Group A beta hemolytic strep
It has characteristic indurations (elevations) - lymphatics have been damage and nowhere for lymph to go
Bulla can also be seen in this condition
Infections due to dog bites
Which body part mostly affected
Which bacteria are involved?
Treatment?
Face > extremeties
Cellulitis is the usual result - rare bone/joint involvement
Mixes flora - Staph aureus & Streptococcus species
Pasteurella spp.
Anaerobes
Treatment:
β-lactam/βL-ase inhibitor IV or
Ceftriaxone IV + Metronidazole PO or IV
If MRSA - add Vancomycin IV
Cat bites infections
Which body part mostly affected?
Involveent?
**Which pathogen is mostly involved?
Treatment?
Cats are more infectious than dogs
They mostly involved the upper extremeties
There can be seeding in the bone/joint/tendon
Pathogens mostly involved is - Pasturella multocida (not very virulent but in soft tissue and bone can progress very rapidly
Treatment: Ampicillin IV or Ceftriaxone IV
What is the treatment of beta stroptococcus and Staph aureus?
If wound, foreign body, pus (r/o MRSA) - Vancomycin IV
No pus, or MSSA - Cefazolin or Nafcillin IV
What are the systemic clinical clues for a necrotizing soft tissue infection?
(MAST)
Multi-organ failure
Altered mental status
Shock
Systemic Toxicity
What are the local clinical clues for necrotizing soft tissue infections?
Severe pain or painless
Gas in soft tissues (crepitus)
Non-red color - blue/grey/black/purple
Hemorrhagic vesicles/bullae
Eschar - black color
Slough
What causes monobacterial necrotizing soft tissue infections in immunocompetent hosts?
β-Streptococcus - Cellulitis/Fasciitis/Myositis
Clostridium spp. - Myonecrosis/Cellulitis
What causes streptococcal gangrene?
β Streptococcus species:
- Group A (S. pyogenes)
- Group B (S. agalactiae)
Exotoxins - act as superantigens
→ necrotizing fasciitis/myositis
→ cytokine storm → sepsis/multi-organ failure
Spontaneous or following minor trauma
What is the therapy for Streptococcal gangrene?
Clindamycin (X48 hrs) plus Vancomycin IV
or
Clindamycin (X48 hrs) plus β-Lactam IV
SURGERY - urgent
Debridement
Decompression
What causes monobacterial necrotizing tissue infeection in immunocompromised hosts?
CIRRHOSIS
- Vibrio vulnificus
- Wound infection - brackish water
- Raw shellfish ingestion – bacteremia/cellulitis
- Capnocytophaga canimorsus
- Dog bite wound infection
ACUTE LEUKEMIA (with neutropenia)
- Ps. aeruginosa - Ecthyma Gangrenosum
What causes necrotizing clostridial infections?
necrotizing soft tissue injuries (motor vehicle accidents, gun shot wounds etc)
Decreased reduction and oxidation potential of tissue
Contamination or foreign body material
How do you manage clostridial fasciitis/cellulitis?
ANTIBIOTICS
Penicillin (or Ampicillin or Clindamycin) IV
SURGERY
Debridement (Cellulitis)
Amputation (Myositis)
Hyperbaric oxygen if readily available
Don’t delay surgery
Progressive synergestic necrotizing fascitis/cellulitis pathogens?
Gram-negative Bacilli
Anaerobes – Bacteroides species
Staph aureus
β-hemolytic Streptococcus species
Progressive synergestic necrotizing fascitis/cellulitis epidemiology
Mostly seen in patients with diabetes and those with decubitus ulcers
DIABETES MELLITUS
- Distal lower extremities
- Neuropathic/vasculopathic ulcers
- Neglected traumatic wounds
- Perineum (Fournier’s Gangrene) - spontaneous
DECUBITUS ULCER
- Elderly
- Immobile/bed-bound
What is the therapy for progressive synergistic necrotizing fascitis?
Surgery
- Debridement
- Repeat daily as needed
Antibiotics - broad spectrum vs. GNBs & anaerobes & GPCs
- 3rd gen Ceph + Metronidazole (or Clindamycin) IV OR
- Fluoroquinolone + Metro (or Clindamycin) IV OR
- Carbapenem (Imipenem) IV
