Skin and Soft Tissue Flashcards
What are the 4 classic presentations of an SSTI?
1-Rubor (erythema)
2-Calor (warmth)
3-Tumor (edema/swelling)
4-Dolor (tenderness)
What term is described as a crackling or the feeling of rice krispys under a tissue?
Crepitus
*often gas gangrene
Rebound of a furuncle is called what?
Fluctuance
Bruising can be called?
Purpura
Another word for blisters is?
Bullae
Folliculitis is a minor infection associated with friction and sweat gland activity and is caused by what?
- Staph aureus
- Hot tub folliculitis is pseudomonas aeruginosa
*treated with soap and water and topical antibiotics
Acne is inflammation of hair follicle and associated sebaceous gland and is caused by what?
Propionibacterium acnes as well as hormonal influences
Pus is comprised of what?
WBC’s accumulation and cellular debris
A fluctuant, tender, erythematous nodule with surround erythema that results from the nacres/liquefying of tissue is likely what?
Soft tissue abscess
*often polymicrobial but staph aureus most common. Treated by incision and drainage, maybe systemic antibiotics
Multiple furuncles (boils) congregate to form what?
Carbuncle
*infection spreads to subcutaneous tissue, usually s. aureus, treated by I and D
“Ringworm” is really a yeast infection in the keratinized layers cause by what?
Dermatophyte fungi
What are the 3 most common causes of body skin yeast infections?
1-Trichophyton
2-Microsporum
3-Epidermophyton
*Candida albicans is most common vaginal
Impetigo has characteristic honey crusts, is highly contagious, is in the epidermis and is caused by what?
Group A strep or Staph aureus
Erysipelas is a deep dermis infection with rubor, calor, tumor and dolor and is caused by what?
Group A strep
*treat with penicillin usually
Cellulitis is caused by group A strep or staph Aureus and effects primarily what skin layer?
Subcutaneous tissue
“Flesh eating” Group A strep or S. aureus that cause a rapid extension of infection are referred to as?
Necrotizing fasciitis
*able to digest fascial barriers. many times polymicrobial with G (+) and anaerobes
Which anaerobe has spores and can cause necrotizing fasciitis?
Clostridium perfringens
Polymicrobial infection of the genitals and perineum is referred to as?
Fournier’s gangrene
*a necrotizing fasciitis
Poor circulation near a wound is optimal for what organisms?
Anaerobes
What potential pathogen is the all-time champ, is acute, aggressive, causes locally destructive purulent lesions, and colonizes anterior nares in 10-30% of the population?
Staphylococcus Aureus
*gram (+) cocci
Alpha-toxin of S. Aureus causes what?
Scalded skin syndrome
A problem in super absorbent tampons or sinus surgeries if the dressings are not changed frequently, TSST-1 is an S aureus toxin that causes what?
Staph toxic shock syndrome
What does the staph exotoxin do in the GI tract?
Acts as an enterotoxin and causes staphylococcal food poisoning
What gene is required for MRSA strains?
mecA gene (makes new PBP with reduced affinity for B-lactams)
What are the drugs of choice for MSSA?
- Anti-staph pcn (nafcillin, oxacillin)
- cephalosporins
With higher risk in crowded living, skin-skin contact, poor hygiene and IV drug users, what is the treatment for MRSA?
- Trimethoprim-sulfa
- doxycycline
- vancomycin,
- linezolid
- daptomycin
What are two sequelae of Group A strep (strep pyogenes)?
- Rheumatic fever after pharyngitis
- Post-strep glomerulonephritis after pharyngitis
Which Strep exotoxins can act as super antigens?
Exotoxins A and B
Which strep exotoxins are cytotoxic and lyse leukocytes, tissue cells and platelets?
Streptolysins O and S
What are three strep inflammatory enzymes?
1-Streptokinase (protease)
2-Hyaluronidase (degrades carbohydrate)
3-DNase
What anaerobic, spore-forming, gram-positive rod with square ends is found in soil and human colon and produces hydrogen, CO2 gases and exotoxins?
Clostridium perfringens
*can result in gas gangrene. more typical in crushing injuries where blood flow is decreased
What gram negative rod is associated with animal bites?
Pasteurella multocida
What gram negative rod is a prototypical non-fermenter, is an environmental pathogen and causes hot tub folliculitis or infection after burns?
Pseudomonas aeruginosa
What gram negative rod is in salt-water environments (shellfish) causes fever, sepsis and hemorrhagic bullae and is associated with iron overload (cirrhosis)?
Vibrio Vulnificus
A mycetoma of “Madura foot” is caused by what?
- Bacterial actinomyces or nocardia
- Fungal
“Rose gardeners thumb” presents usually as erythematous furuncles up the lymph chain and is caused by what?
Sporothrix schenckii
*Called sporotrichosis
What is the best specimen when trying to diagnose an SSTi?
Pus or fluid from the infection
When the abscess is in the skin think?
Staph aureus
When the abscess is in the mouth/rectum/vagina think?
Polymicrobial
With Cellulitis and erysipelas think?
Strep Pyogenes (group A strep)
