Bacterial Skin and Soft Tissue Infections - Wordpress Wordpress by cuiliqing


									Bacterial Skin and Soft Tissue Infections
                                                Abscess Forming Infections
    Types of Infection          Etiological Agents     Structure Involved                    Clinical Features
Folliculitis                Staphylococcus aureus    Localized infection   1. Small
   Inflammation and                                    in the               2. Erythematous
    infections of hair                                o Hair follicles          a. Papules
    follicles                                         o Axillae                 b. Pustules
                                                      o Scalp                3. Course of folliculitis
Treatment                                             o Ear canal               a. Develop into Furuncle
1. Cloxacillin                                            Leads to Otitis         i. Deeper inflammatory nodules
2. Surgery                                                   Externa            b. Furuncle can then extend deeper into
  a. Carbuncle                                                                       subcutaneous fat called Carbuncle
                                                                                   i. Bigger
                                                                                  ii. Deeper
                                                                                 iii. Due to multiple draining sinuses
                                                                                iv. Occurs at
                                                                                      1. Nape of neck
                                                                                      2. Thigh
                                                          Spreading Infections
1. The most common superficial epidermal infection
2. Due to
  a. Poor hygiene
  b. Hot and humid climate
3. Common in children
    Types of Infection         Etiological Agents               Structure Involved                     Clinical Features
Non bullous Impertigo     Streptococcus pyogenes              Epidermis             1. Serous exudates in the vesicles
 More common             Nephrotogenic strain of                                    2. Ruptures to produce GOLDEN-CRUSTED
 Begins with small         Strep pyogenes type M49                                      erosions
    vesicles               o Causing non-
   o Ruptures causing          suppurative sequale
      superficial spread   o Acute
Treatment                      glomerulonephritis
1. Penicilin
Bullous Impertigo         Staphylococcus aureus                 Epidermis           1. Bullae or vesicles containing turbid fluid (serum)
                            phage type 71                                             2. Dangerous in infant, requires systemic
Treatment                  o Produces exfoliatin                                         antibiotics
1. Cloxacillin

Cellulitis                          Streptococcus pyogenes      Epidermis           1. Localized area of
   A diffuse                       Staphylococcus aureus                             a. Mildly painful edema
    inflammation and                 (polymicrobial)                                   b. Warmth
    infection of                                                                       c. Swollen
    superficial skin layers                                                           2. Severe systemic infection
                                                                                       a. Fever
                                                                                       b. Rigors
Erysipelas                          Streptococcus pyogenes      Underlying dermis   1. Usually occurs at the face
    Deeper form of cellulitis      Staphylococcus aureus       Lymphatic           2. Involvement of lymphatic drainage gives rise to
    Perdisposing factors
  o   Diabetes mellitus              (polymicrobial)              channels               clearly demarcated area of
  o   Venous stasis                                                                    a. Erythema
  o   Alcohol abuse
Treatment                                                                              b. Induration
    Cloxacillin
   Penicillin
                                                    Necrotizing infections
    Types of Infection          Etiological Agents         Structure Involved                       Clinical Features
Gas                           Clostridium perfringens    Muscles              Pathogenesis
                              Clostridium septicum       Soft tissues         1. Production of alpha toxin  tissue death
Gangrene/Clostridial                                                            2. Production of gas in the necrotic lesions
Myonecrosis                                                                     3. Cell death leads to destruction of blood supply to the
  Predisposing factors                                                             affected tissues
                                                                                4. Favors anaerobic condition, which in return organism will
   (60-70%)                                                                         further replicate
  o Motor vehicle                                                               Features
    accident                                                                    1. Initial presentation appears 4-6 hours after trauma
  o Penetrating injury                                                          2. Local tenderness
  o Crush injury                                                                3. Skin appears
                                                                                   a. Stretch
Treatment                                                                          b. Shining
 Surgical debridement                                                             c. Later blackens
  o Amputation might be                                                         4. Foul smelling discharge
    required                                                                    5. Crepitus
 Penicillin                                                                    6. Systemic symptoms
                                                                                   a. Sweating
                                                                                   b. Tachycardia
Necrotizing Fascitis           Streptococcus               Widespread         1. Devascularization of
 Acute and highly toxic        pyogenes                     infection of the      a. Skin
Predisposing Factors           o Flesh-eating bugs           fascia                b. Muscle
1. Post surgery                Polymicrobial                                      c. NOT INCLUDING BONE
2. Post trauma                 o Aerobic/facultative                            2. Skin necrosis
3. Strep pyogenes skin            anaerobe                                      3. Bullae formation
    infection                     Staph aureus                                 4. Surrounding tissue edema and inflammation
4. Diabetes mellitus              Strep spp.                                   5. Gangrenous
                                  Enterococcus                                 6. Crepitus
Treatment                         Enterobacteriacea                            7. Pts appears toxic with soft tissue pain
1. Surgical exploration        o Anaerobic
  a. Removal of death tissues     Bacteroides spp.
  b. Determine extend of          Clostridium spp.
    tissue damage
2. Combination of
                                    Systemic Bacterial Infection with Cutaneous Involvement
   Types of Infection            Etiological Agents           Structure Involved                      Clinical Features
Staphylococcus               Staphylococcus aureus         1. Cutaneous           1.   Toxin causes loss of overlying skins
Scalded Skin                  o Exfoliatin strain              manifestation       2.   Toxiemia
                                                             a. Epidermis          3.   Fever
Syndrome (SSSS)
                                                                                   4.   Death
1. Also known as
  a. Infant
   i. Ritter’s diseases
      (not to be
      confused with
      Ritter’s syndromes)
  b. Children/adult
   i. Toxic epidermal
2. May occur
    sporadically or in
1. Fluid replacement
2. Cloxacillin
Toxic Shock                     Staphylococcus aureus      1. Involved multiple   1. Happens in women using tampon
Syndrome                        o TSST-I toxin (exotoxin)      organs              2. Can also occur in non-genital site in men
                                                            2. Cutaneous           3. Erythematous rash
Treatment                                                      manifestation       4. Skin dequamation of
1. Fluid replacement                                         a. Epidermis and       a. Palms
   therapy                                                       dermis             b. Soles
2. Cloxacillin
                                                 Micellaneous Skin Infections
             Types of Infection                 Etiological Agents                            Clinical Features
Erysipeloid                                  Erysipelothrix           1. Tender
 Suspect in handlers of                      rhusiopatheiae           2. Blue-red discoloration of the skin
   o Fishes                                                            3. Well demarcated
   o Meats

Erythrasma                                   Corynibacterium          1. Often assymptomatic
                                              minutissimum             2. Slowly enlarging area of dry skin which either
                                                                          a. Pink
                                                                          b. Brownish
                                                                       3. Erythema spreads in moist and skin folds such as
                                                                          a. Axillae
                                                                          b. Groin
                                                                          c. Between toes
Cat Scratch Disease                          Bartonella Henselae      1. Following cat scratch
Treatment                                                              2. Nodule formation at scratched area
1. To shorten the course of the disease                                3. Regional lymphadenopathy
  a. Tetracyclin                                                          a. Resolves in 1-6 months
                                                                       4. Self limited
  b. Erythromycin
Cutaneous Anthrax                            Bacillus anthracis       1.    Inflammed lesion with surrounding edema
 Due to direct inoculations from                                      2.    PAINLESS
   o Infected animals                                                  3.    Variable skin lesions
   o Contaminated animal products                                      4.    If not treated, may progress into
                                                                            a. Septiceamia
                                                                            b. Death
1. Penicillin

Animal’s Bite Infections                      Pasteurella multocida   1. Skin loss leads to sf tissue damages
                                              Often polymicrobial
Treatment                                                              2. Exposure to animal saliva and foreign particles lead to
                                              o Aerobes
1. Thorough cleaning                                Staph spp.           secondary skin infection
2. Debridement of all damaged tissues               Strep spp.        3. Cellulitis
3. Combination antibiotics                    o Anaerobes              4. Lymphagitis
                                                    Bacteroides       5. Localized abscess
4. Penicillin for Pasteurella multocida             Anaerobic cocci

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