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Flashcards in Necrotising Faciitis Deck (16)
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2 bacterial causes of toxic shock syndrome

Staph aureus
Strep pyogenes


Toxic shock definition

Acute toxin-mediated illness resulting in shock and multi-organ failure
Usually from S aureus or S pyogenes
Shock is persisting hypotension despite adequate volume resuscitation requiring vasopressor support


Toxins involved in toxic shock
1. 2 from S aureus
2. 1 from Strep

1. Toxic shock syndrome toxin-1 (TSST-1), Staphylococcal enterotoxins (SEB and SEC)
2. Streptococcal pyrogenic exotoxin A


Super antigens

The toxins implicated in TSS
Binds as unprocessed proteins to both MHC II and to the TCR
Leads to non specific activation of T cells


Staphylococcal Toxic Shock

Seen in association with highly absorbent tampons
Initial sx: fever, myalgias, GI upset
Can develop macular rash
Progressive hypotension/organ dysfunction
Skin desquamation occurs late
Rarely associated with bacteremia
Tx with source control and supportive care for hypotension


Antibiotic management for staphylococcal toxic shock

Broad coverage: Vancomycin
Can step down to cloxacillin if MSSA identified
Consider adding clindamycin


Streptococcal toxic shock

Invasive disease (bacteria isolated from a normally sterile site) associated with:
pre existing skin lesions, varicella infection in children, DM, injection drug use, post-partum setting
Higher rate of bacteremia in 60% of cases


M protein

Group A strep
Critical virulence protein
Helps with adherence to epithelium
Assists in evading phagocytosis/antibody binding
May contribute to additional cytokine release


Necrotizing Fasciitis

Severe and rapidly progressive infection of the muscle fascia and subcutaneous fat
Can involve the epidermis
Can involve adjacent muscle
Classically in the limbs (lower > upper)


Type 1 vs 2 of necrotizing faciitis

Type 1: polymicrobial, including gram - and anaerobic organisms
Type 2: group A strep (mono microbial)


Potential initial clues to necrotizing fasciitis

Severe pain out of keeping with clinical findings
Progressive edema beyond area of erythema


Late clinical signs of nec fascitiis

Development of bullae
Evidence of gas in the soft tissues (crepitus)
Cutaneous anesthesia


How is diagnosis of nec fas made?

Biopsy for an urgent gram stain


Antibiotic management for
1. Suspected necrotizing fasciitis
2. Proven GrpA strep

1. Vanco PLUS pip-tazo, +/- clindamycin
2. Penicillin PLUS clindamycin
Minimum 14d if bacteremic - maybe more


Rationale for using clindamycin in nec fasc

Penicillin is less effective once bacteria are in the steady state, but clindamycin remains active
Potential benefits of decreasing protein production (like M protein toxin)


Rationale for using IVIG

Neutralization of the superantigens
Downregulation of chemokine receptors
Decrease in production of inflammatory cytokines
3 days of IVIG is helpful!