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53 Cards in this Set

  • Front
  • Back
Major portals of entry for Strep infections
Upper respiratory tract, skin
3 delayed sequelae of GABHS
scarlet fever, rheumatic hart disease, glomerulonephritis
what 2 conditions can follow strep pharyngitis
Scarlet fever, rheumatic heart disease
What type of infection does post strep glomerulonephritis follow
strep skin infections
Impetigo
a. what layers does it infect
b. transmission
c. 2 causative organisms
d. course
a. superficial - epidermis
b. direct contact, transmisson from individuals, arthropods
c. staph and strep
d. purulent --> resolves on its own
Patient has multiple thick-crusted, golden-yellow lesions or pustules that develop within 10-14 days on lower extremities, face and scalp

2 organisms that cause this?
what layers are implicated?
treat?
impetigo

staph or strep

epidermis/dermis

bacitracin (GABHS), retapamulin (strep and staph)
Serotype implicated in invasive GABHS disease
M1 and M3
What is erysipelas?

2 types?

course?
acute inflammation of skin with involvement of cutaneous lymphatics --> advancing raised, well-demarcated margins

facial (precedes sore throat)
trunk (surgical or trauma)

facial resolves on its own, trunk lesions progress
Cellulitis

what layer is implicated?

where does it infect?
lower dermis

sites of burn, wound, or surgery
How do you know if cellulitis has progressed to lymphangiitis?
appears as a linear red streak that spreads from distal to proximal along lymph pathway

accompanied by swelling, tenderness, redness, pain, swelling of LNs
2 ways in which cellulitis is different from erysipelas
1. lesion of cellulitis is not raised
2. cellulitis has indistinct borders
Treatment for strep infections
IV penicillin
Layers implicated in necrotizing faciitis and myositis
deeper subcutaneous tissues and fascia
patient has
-high fever and toxicity
-extreme prostration (pain out of proportion to exam)
-rapidly spreading inflammatory process with bullae (yellow liquid)

dx?
treat?
necrotizing fasciitis

surgical debridement, antibiotics
How does one often acquire myositis?
penetrating trauma into muscle
Strep toxic shock syndrome

a. how is it acquired
b. how does it spread
c. symptoms
a. infected wound
b. bacteremia --> superantigen toxin, often infects muscle
c. fever, rash, shock, myositis
how strep toxic shock different from staph toxic shock?
strep = bacteremia

staph = no bacteremia (toxin enters blood stream), less fatality
Patient comes in with
-fever, pain in extremities
-tachycardia, hypotension
-necrotizing fasciitis
-confusion, coma
strep toxic shock syndrome
Treatment for Strep toxic shock
-Pen G
-first gen cephalosporin or vancomycin
-clindamycin (Eagle effect = kills bact in stationary phase, also inhibits toxin production)
What are superantigens
toxins that bridge the TCR and the APC --> massive cytokine release, lymphocytes activated --> fever, shock hypotension
2 superantigens produced by GABHS

secreted protease that contributes to tissue destruction
SpeA and SpeC

SpeB
types of clostridium
a. resident in soil, causes gangrene
b. colonizes intestine of animals
c. associated with necrotizing enterocolitis
a. A
b. B to E
c. C
Most prominent clostridium toxin
Alpha = lethal toxin

Phospholipase C --> disrupts cell membranes, hemolysin, increases vascular permeability by killing endothelial cells, causes necrosis
What does c. perfringens cause
cellulitis --> necrotizing fasciitis, suppurative myositis, myonecrsis
What is suppurative myositis
abscesses in muscle without necrosis of muscle, lacks systemic toxicity
In clostridial myonecrosis, why is there a lack of inflammatory cells
toxins lyse the WBCs entering the tissue
what is the general term for superficial purulent infections of the skin

2 types
pyoderma

prmary = healthy skin
secondary = superinfection of skin previously affected by trauma or chornic skin disorder
Subtypes of pyoderma

Thin vesicles and blisters with honey-colored crust that heal without leaving scars; these are contagious
impetigo
Subtypes of pyoderma

impetigo that extends deeper into epidermis; leaves scars when it heals
ecthyma
Lesion that looks like ecthyma, seen in immunocompromised individuals from pseudomonas
ecthyma gangrenosum
Subtypes of pyoderma

S. aureus spreads through dermis and subcutaneous tissue --> coalesce --> drain out of skin at several points
carbuncle
Subtypes of pyoderma

superficial skin infection that spreads to lymphatics
-raised border, tender, well-demarcated
-associated with diabetes, chronic venous inusufficiency, chronic lymphatic obstruction
erysipelas (staph or GABHS)
Subtypes of pyoderma

-tender, warm, red plaque
-no raised border
-systemic features of sepsis
cellulitis
Cause of cellulitis

perianal cellulitis in children
-associated with acute glomerlonephritis
streptococci
Cause of cellulitis
-immunocompromised host
-associated with ecthyma gangrenosum
pseudomonas aeruginosa
Cause of cellulitis

injuries in fresh water
aeromonas hydrophila
Cause of cellulitis

Salt water injuries or ingestion of raw seafood

Diabetics and cirrhotics vulnerable, esp. liver disease
vibrio vulnificus
Cause of cellulitis

trauma from dirty wounds

causes gas formation but minimal toxicity
clostridium
Cause of cellulitis

-food handlers, seafood
-tender, red-purple plaques
erysipelothrix rhusiopathiae
Cause of cellulitis

-dog or cat bites
-on hands and feet
-rapidly progressive
pasteurella multocida
Cause of cellulitis

immunocompromised host
crytococcus neoformans
Necrotizing faciitis

what layers?
SKIN, SUBCUTANEOUS TISSUE, DEEP FASCIAL PLANES
Disease in which toxins secreted by bact cause tissue separation along fascial planes --> vascular thrombosis --> tissue ischemia --> infarction of superficial layers of skin

how do you treat?
necrotiizing fasciitis

treat with surgery, hyperbaric oxygen
Types of necrotizing fasciitis

-mixed due to anaerobes, strep, staph, coliforms
-painful, but w/o systemic involvement
-subacute presentation; found in surgical wounds
progressive bacterial synergistic gangrene
Types of necrotizing fasciitis

-all layers of skin
-rapid onset and extension
-near GI or GU
-painful lesions, septic
-diabetics, obese, elderly

what if it involves the scrotum
necrotizing fasciitis type I (synergistic necrotizing cellulitis)

Fournier's gangrene
Types of necrotizing fasciitis

-Specific M-types of GABHS
-can be after surgery or not
-pain, swelling, spread, systemic toxicity
-gas formation seen on xray

treat?
Type II (Streptococcal gangrene)

treat with penicillin and clindamycin
Types of necrotizing fasciitis

-monomicrobial (c. perfringens)
-contamination of wounds by soil, feces, or site of tissue hypoxia
-Death may occur in 24 hrs
-gas in soft tissues, palpable on physical and radiographical exam

dx? treat?
necrotizing pyomyositis (clostridial myonecrosis)

penicillin + clindamycin
disease causes
-swollen, painful muscle, induration
-progresses to point tenderness, fever, abscess
-progresses to systemic illnes with bacteremia (fever, hypotension, sepsis)

CT/MRI reveals abscessies

dx?
cause?
how does it get in and spread?
pyomyositis

staph aureus

gets into muscle following blunt trauma, spreads hematogenously
2 things on differential if soft tissue infection is
-rapidly spreading
-fever
-hypotension
-crepitation
-bullae
-discolored
-severe pain
necrtizing fasciitis or gas gangrene
Classification of infection that is
-superficial
-gram pos
-no complicating medical illness

treat?
uncomplicated

treat with antibiotics only
-vancomycin, daptomycin, and linezolid (for severe)

-doxycycline, clindamycin, or TMP-SMX for less severe
Classification of infection that
-involves more than one layer
-may involve abscesses
-occurs in presence of immunocompromised or vascular insufficiency
-polymicrobial

treat?
broader spectrum Abs, surgical

Complicated infections
4 indications for oral therapy
-not systemically ill (no fever or leukocytosis)
-not immunocompromised
-able to take orally
-responsible enough to come back if things get worse
optimal duration of therapy
1-2 weeks