Cellulitis, Abscess Flashcards
Cellulitis pathophysiology
Cellulitis is an infection of the deeper layers of the dermis. It can be non-purulent or purulent (e.g., associated with pustules or a skin abscess)
Infection can progress into deeper tissues to the point where it may even affect bone.
Cellulitis Pathogens: Gram-positive cocci causing non-purulent cellulitis
Beta-hemolytic streptococci, especially group A streptococci (e.g., S. pyogenes)
Cellulitis Pathogens: Gram-positive cocci causing purulent cellulitis
Purulent cellulitis or abscess: S. aureus, including MRSA
Abscess
Features of cellulitis + a focal collection of pus within the subcutaneous tissue
Cellulitis DX - imaging type?
Advanced imaging (e.g., CT with contrast) of an affected extremity if there is concern for a necrotizing skin and soft tissue infection or abscess
Cellulitis DX - in cases where there are notable systemic symptoms (e.g., fevers, rigors)
Blood cultures
cellulitis dx in cases that do not respond to appropriate therapy, in immunocompromised patients, and/or when the diagnosis of cellulitis is uncertain??
A skin biopsy may be helpful
why are Superficial wound cultures are not useful in isolating organisms?
as they are often polymicrobial and do not reliably distinguish the causative organism from normal skin flora
BACTEREMIA
- Presence of bacteria in the blood stream
- May occur spontaneously during certain tissue infections, with use of indwelling GU or IV catheters, or after dental, GI, GU, wound-care, or other procedures.
SEPSIS
Life-threatening organ dysfunction caused by a dysregulated response to infection.
Septic shock:
Critical reduction in tissue perfusion
Acute failure of multiple organs
RISK FACTORS FOR SOFT TISSUE INFECTIONS
- Immunosuppressed
- Chronically ill
- Prior or chronic skin infections
- Implanted devices
- Occupational exposures: zoonoses, ubiquitous pathogens causing skin infection
DDX FOR CELLULITIS (6)
- DVT
- Necrotizing fasciitis
- Erysipelas
- Venous stasis
- Contact dermatitis
- Underlying osteomyelitis
Necrotizing fasciitis
Aggressive, morbid, and limb- and life-threatening infection within the deep layers of the skin
Necrotizing fasciitis lab results?
If suspected, what do you do?
Labs: Non-specific, but can have leukocytosis, hyponatremia, elevated inflammatory markers
Consult general surgery immediately if you suspect necrotizing soft tissue skin infection (SSTI)
