Impetigo Flashcards
What are conditions that can set one up for SSTI?
high concentrations of bacteria (more than 105 microorganisms),
too much moisture present on the skin,
lack of adequate blood supply,
the presence of nutrients that bacteria use,
and damage to the corneal layer allowing for bacterial penetration.
What should the physical exam for SSTI look for?
The physical examination should include descriptions as to the amount and location of dolor(pain), calor(heat), rubor(erythema), and tumor (swelling).
If these symptoms are obvious or there are systemic signs and symptoms such as fever, hypotension and tachycardia - thats not great
Other clues to potentially deep, and more sever SSTIs can be pain disproportionate to physical findings, violaceous (bluish, purple in colour) bullae, cutaneous hemorrhage, skin sloughing, skin anesthesia, rapid progression of the SSTI, gas in tissue or obvious necrosis.
What is the most common SSTI??
IMPETIGO
What age does impetigo occur in?
Kids two to 5 years old, and often occurs when there is excess warmth and humidity present in the environment.
Describe which bacteria causes bullus impetigo, and what it looks like?
-S. Aureus
- S. Aureus produces a toxin that causes vesicles to rapidly progress into bullae containing clear yellow fluid. The bullae soon rupture and create thin light brown crusts.
- Regional lymph nodes may be enlarged.
What causes non-bullous impetigo, and what does it look like?
May be cause from B-hemolytic streptococci, or S. S aureus or both in combo.
Non-bullous Impetigo begins as red papules that quickly turn into vesicles and pustules that rupture, ultimately forming honey-colored crusts on an erythematous base.
Is non-bullous impetigo caused exclusively by B-hemolytic streptococci?
This is “truthy” in that β-hemolytic streptococci can be a major cause, but you can never rule out S. aureus being the cause or a secondary infection, so it is best to treat with a medication that covers both bacteria. Cultures may be done but in most cases the treatment will probably be empiric.
When should you consider topical antibiotics in impetigo?
If it is just a few lesions and there is not local spread, a topical antibiotic such as mupirocin or fusidic acid three times daily or retapamulin twice daily for 5 days should clear it up
When should you consider systemic antibiotics in impetigo?
If there are numerous lesions or the entire pre-school class has it, you need to go with systemic antibiotics.
Which systemic antibiotics can you go with if you need it for impetigo (NON-MRSA)
** need to go with agents that are going to cover both B-hemolytic stretococci and S. Aureus**
- Cloxacillin - GOOD
- Cephalexin - GOOD
What systemic antibiotic can you use if suspecting MRSA impetigo?
- Doxycline - Not for kids under 8
- TMP-SMX
- CLindamycin (This one sucks)
Generally - crust removal by soaking in warm soapy water also may be helpful in providing symptomatic relief.
How does bacitracin work and what is it spectrum of activity?
Bacitracin inhibits cell wall formation by interfering with the transfer of peptidoglycan subunits to the growing cell wall. Thus, cell wall production is inhibited. inhibits staphylococci, streptococci, and a few gram-negative bacteria (Neisseria species and Haemophilus influenzae)
How does fusidic acid work and what does it cover?
Fusidic Acid is a steroidal antibiotic that inhibits protein synthesis, specifically at the translation. It primarily just covers Staphylococcus species.
How does gramicidin work? What does it cover?
Gramicidin is a channel-forming ionophore that renders biological membranes permeable to specific cations which disrupts cellular ionic homeostasis.
It is mostly active against gram-positive organisms.
HOw does mupirocin work, and what does it cover?
Mupirocin inhibits protein synthesis by binding to bacterial isoleucyl-tRNA synthetase
Most gram-positive aerobic bacteria, including methicillin-resistant S aureus (MRSA), are susceptible to mupirocin.
