Skin and soft tissue infection Flashcards
Cellulitis and erysipelas are described as acute spreading inflammation of the dermis and subcutaneous tissues with prominent ______ involvement
Lymphatic
Which has a well-demarcated and raised border- cellulitis or erysipelas?
Erysipelas
What is the best way to treat lymphedema associated with cellulitis
Elevation
List three pathophysiologic components of cellulitis
Portal of entry
Lymphedema
Causative agent
List some common portals of entry
Tinea pedis Diabetic foot ulcer Trauma Eczema Psoriasis May have none evident
List some causes of chronic lymphedema
Venous insufficiency (due to morbid obesity, heart failure, kidney disease)
Prior surgery- ex vein harvest, node dissection
Prior radiotherapy
Prior DVT
PREVIOUS CELLULITIS
Erysipelas is commonly caused by _________. Non-purulent cellulitis is commonly caused by _____. Purulent cellulitis is commonly caused by _________
Erysipelas: Group A Strep
Non-purulent cellulitis: Group A Strep
Purulent cellulitis: S. aureus
What distinguishes purulent from non-purulent cellulitis?
Presence of draining furuncle, carbuncle, boil, abscess
Purulent cellulitis caused mostly by S. aureus, commonly MRSA
Describe why thorough history/ epidemiology is important in making a diagnosis of cellulitis
Can give insight into abnormal/ atypical microbial causes.
Ex animal bites- Pasteurella, salt water- Vibrio vulnificus
List some risk factors for CA-MRSA
History of MRSA colonization
History of recurrent skin disease
SSTI with poor response to beta lactams
History of crowded living conditions, contact sports, MSM, IDU, shaving
Native American, Pacific Islander, Alaskan Natives
Describe some ways to make a microbial diagnosis in cases of cellulitis
Blood cultures if hospitalized (low yield)
Needle aspiration from fluctuant areas or bullae (still only 25% yield)
ASO titer for GAS
MRSA swabs from nares, groin, axilla- still false negatives and positives
Describe components of management of cellulitis
Look for unusual bacteria
Find and treat portal of entry
Manage lymphedema
Use antibiotics based on expected organism
List antibiotics used in purulent cellulitis
MRSA/MSSA
doxycycline, minocycline, clindamycin, linezolid, vancomycin, daptomycin, ceftaroline
List antibiotics used in non-purulent cellulitis
Group A Strep
penicillin, amoxicillin, dicloxacillin, cephalexin, clindamyin, nafcillin, ceftazolin, vancomycin
Describe management of recurrent cellulitis
Portal of entry management
Lymphedema management
Low dose antibiotic prophylaxis
True or false: treatment for necrotizing fasciitis is IV antibiotics
False, antibiotics alone are not sufficient.
Need early and aggressive surgical debridement
List clinical clues that suggest life threatening necrotizing SSTI
Pain out of proportion to what is seen
Systemic toxicity- abnormal kidney/liver tests, anion gap, TSS, shock
Rapid progression
Necrosis
Anesthesia- indicates infarction of nerve supply
List risk factors for necrotizing SSTI
Trauma Surgical wound Peripheral vascular disease Diabetes Obesity Alcohol abuse, IDU Immunocompromised
Acute diabetic foot infections are commonly caused by
S. aureus, streptococci
Chronic neuropathic diabetic foot ulcers are typically _________
polymicrobial
S. aureus, Coagulase-negative Staph, enterococci, GBS, Gram neg aerobes, anaerobes
Require broad spectrum antibiotics
For all chronic diabetic foot ulcers, clinicians should be concerned about/ look for signs of _____
osteomyelitis
Neutropenic hosts are more likely to have SSTI caused by ___
Aerobic GNR + staph/strep (fungi later)
Always include potent anti-pseudomonal coverage
Ecthyma gangrenosum- Pseudomonas skin infection seen in neutropenic hosts
CMI impaired hosts are more likely to have SSTI caused by ______
mycobacteria, Nocardia, cryptococcus, histoplasmosis, other fungi, VZV, HSV, CMV, scabies
