Skin and Soft tissue infections - Glew Flashcards

1
Q

The hair follicle is the portal of entry for what pathogen?

A

Staph. aureus

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2
Q

What are the three possibile types of skin and soft tissue infections?

A

Superficial focal - impetigo

Superficial spreading - cellulitis

Deep necrotizing

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3
Q

What are the lesions that can occur in a superfcial focal skin infection?

A

Impetigo - staph aureus > beta strep

Folliculitis - staph aureus

Furuncle - staph aureus

Carbuncle - staph aureus

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4
Q

Honey colored crusts are characteristic of what?

A

They are a superficial local lesion - impetigo from a staph aureus infection

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5
Q

Bullous impetigo is what type of a skin infection and what causes it?

A

It is a supeficial local lesion from staph aureus

Neonatal scar syndrome can result from staph aureus infection in children

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6
Q

What is folluculitis?

A

A hair follicle inflammation (area of puss limited to the dermis). This is due to staph aureus which spreads thgouh the hair follicle

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7
Q

What pathogen cuases carbuncles and where on the body do they usually occur?

A

Carbuncles are a result of staph aureus infection and they usually occur on the neck or in places where skin rubs against each other

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8
Q

What is the therapy for pyoderma

A

Emperic tx or if MRSA:

  • Doxycycline
  • Sulfa/Trimethoprim
  • Linezolid

MSSA:

  • Dicloxacillin
  • 1st gen Cephalosporin
  • Clindamycin (risk of C. DIff)
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9
Q

What are possible types of superficial spreading infections?

A

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

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10
Q

What are the factors that help in pyoderma local care therapy

A
  • 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
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11
Q

What are the predisposing conditions for cellulitis?

A

Venous/lymphatic insufficiency

Arterial insufficiency

Obesity

CHF

Diabetes Mellitus

Neuropathy

Decubitus ulcers

Trauma

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12
Q

Cellulitis characteristic

A

Cellulitis has hemorrhagic macules and is caused by Group B beta hemolytic streptococcus

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13
Q

What is erysipelas?

A

“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

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14
Q

Infections due to dog bites

Which body part mostly affected

Which bacteria are involved?

Treatment?

A

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

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15
Q

Cat bites infections

Which body part mostly affected?

Involveent?

**Which pathogen is mostly involved?

Treatment?

A

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

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16
Q

What is the treatment of beta stroptococcus and Staph aureus?

A

If wound, foreign body, pus (r/o MRSA) - Vancomycin IV
No pus, or MSSA - Cefazolin or Nafcillin IV

17
Q

What are the systemic clinical clues for a necrotizing soft tissue infection?

A

(MAST)

Multi-organ failure

Altered mental status

Shock

Systemic Toxicity

18
Q

What are the local clinical clues for necrotizing soft tissue infections?

A

Severe pain or painless
Gas in soft tissues (crepitus)
Non-red color - blue/grey/black/purple
Hemorrhagic vesicles/bullae
Eschar - black color
Slough

19
Q

What causes monobacterial necrotizing soft tissue infections in immunocompetent hosts?

A

β-Streptococcus - Cellulitis/Fasciitis/Myositis
Clostridium spp. - Myonecrosis/Cellulitis

20
Q

What causes streptococcal gangrene?

A

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

21
Q

What is the therapy for Streptococcal gangrene?

A

Clindamycin (X48 hrs) plus Vancomycin IV

or

Clindamycin (X48 hrs) plus β-Lactam IV

SURGERY - urgent
Debridement
Decompression

22
Q

What causes monobacterial necrotizing tissue infeection in immunocompromised hosts?

A

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
23
Q

What causes necrotizing clostridial infections?

A

necrotizing soft tissue injuries (motor vehicle accidents, gun shot wounds etc)

Decreased reduction and oxidation potential of tissue

Contamination or foreign body material

24
Q

How do you manage clostridial fasciitis/cellulitis?

A

ANTIBIOTICS
Penicillin (or Ampicillin or Clindamycin) IV

SURGERY
Debridement (Cellulitis)
Amputation (Myositis)

Hyperbaric oxygen if readily available
Don’t delay surgery

25
Q

Progressive synergestic necrotizing fascitis/cellulitis pathogens?

A

Gram-negative Bacilli
Anaerobes – Bacteroides species
Staph aureus
β-hemolytic Streptococcus species

26
Q

Progressive synergestic necrotizing fascitis/cellulitis epidemiology

A

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
27
Q

What is the therapy for progressive synergistic necrotizing fascitis?

A

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