Skin & Soft Tissue Infections Flashcards
What is the empiric antimicrobial therapy for moderate purulent (furuncle, carbuncle, abscess) infection?
Cephalexin (unless high MRSA prevalence) OR
TMP/SMX OR
Doxycycline
What is the empiric treatment for severe purulent (furuncle, carbuncle or abscess) infection?
Vancomycin
What is the empiric therapy for mild cellulitis, without signs of systemic infection or purulence?
Oral cephalexin x 5 days - can extend if no improvement at completion.
What did the PATCH I trial show?
Patients with at least 2 episodes of cellulitis over the past 3 years were treated prophylactically with oral amoxicillin or cephalexin daily for at least 1 year. This was found to be effective in preventing subsequent attacks while on prophylaxis.
What do the guidelines suggest for cellulitis prophylaxis?
Consider if > or = 3 episodes of cellulitis per year DESPITE controlling other risk factors, such as re-vascularization, wound care, footwear, compression, treated tinea.
What is the role of compression stockings in recurrent cellulitis?
Compression therapy results in lower incidence of recurrent cellulitis.
What is the empiric therapy for suspected necrotizing fasciitis?
Piptazo 3.375 g IV Q6H +
Vancomycin 15-20 mg/kg IV Q12H + Clindamycin 600 mg IV Q8H
How do you treat necrotizing fasciitis secondary to Group A Strep?
Penicillin/Beta-Lactam +
Clindamycin
What are the criteria for streptococcal toxic shock syndrome?
- Hypotension (sBP < 90 mmHg) AND
- Isolation of GAS from a normally sterile site AND
2 of the following:
- Renal Impairment (Cr> 177)
- Coagulopathy (Plt < 100 or DIC)
- Liver Fxn Abnormality (AST/ALT/Tbili 2 x ULN)
- ARDS
- Generalized erythematous macular rash that may desquamate
What precautions due toxic shock syndrome require?
Contact & Droplet
Which microorganism is responsible for green nail syndrome?
Pseudomonas aeruginosa
Which organism should you cover for with malignant otitis externa?
Pseudomonas aeruginosa
Which microorganism is responsible for oral hairy leukoplakia?
EBV
What are the characterisitics of a neuropathic foot ulcer?
- Pressure point ulcers
- Punched out appearance
- Deep ulcer
- Minimal pain
- Warm and dry foot
What are the characterisitics of an arterial foot ulcer?
- Lateral malleolus
- Dry & punctate
- Decreased pulses
- Cold & dry foot
What are the characterisitics of venous foot ulcers?
- Medial malleolus
- Irregular margins
- Shallow depth
- Mildly painful
- Venous stasis dermatitis/lipodermatosclerosis
What has the highest likelihood ratio for an infected foot ulcer?
Pain in a chronic wound (+ LR 11-20)
What is the gold standard for diagnosis of osteomyelitis?
Bone biopsy and culture
What clinical findings has the highest likelihood ratio for osteomyelitis?
ESR > 70 has a + LR of 11
Bone exposure has a + LR of 9.2
Which clinical finding has the best negative likelihood ratio for osteomyelitis?
Negative MRI has a negative LR of 0.14
What is the most common causative organism in native vertebral osteomyelitis?
S. Aureus
If you suspect vertebral OM, what workup is guideline recommended?
- Blood cultures (2 sets)
- Baseline ESR/CRP
- MRI Spine
What is the recommended management of vertebral osteomyelitis?
- Hold abx until biopsy if no sepsis/neurological compromise
- Then start empiric ceftriaxone and vancomycin
- Continue abx for 6 weeks
- Repeat inflammatory markers at 4 week
- Repeat MRI ONLY if poor clinical response
What is the empiric antibiotics for prosthetic joint infection?
Vancomycin and CTX
Antibiotics for 4-6 weeks IV or high dose oral with consideration for chronic suppression w/daily oral abx thereafter
Which trial compared oral to IV antibiotics for bone and joint infections?
OVIVA
What did the OVIVA trial demonstrate?
Patient we’re randomized to IV versus oral therapy. Trial demonstrated non-inferiority, with the caveat that the majority of patients managed had identifiable organisms and were able to use highly bioavailable oral antibiotics.
What is the most common cause of impetigo?
Staphylococcus aureus
What is the empiric treatment for a moderate cellulitis (or other non-purulent SSTI such as impetigo and erysipelas), with systemic signs of infection?
IV cephalosporin (cefazolin)
What are two pathogens that cause necrotizing fasciitis and can be acquired through injury exposure to water?
(1) Aeromonas hydrophilia - freshwater
2) Vibrio vulnificus - Saltwater exposure (consider if underlying liver disease, seafood ingestion as well
How would you treat a Vibrio vulnificus infection?
Doxycycline and ceftazidime
How would you treat an Aeromonas hydrophila infection?
Doxycycline + ciprofloxacin
What are the classic features of Salmonella typhi infection?
Fever & diarrhea in a returning traveller
Rose spots
Faint pink macules on lower chest and upper abdomen
What causes oral hairy leukoplakia?
EBV - often in the context of HIV
White plaque that does no scrape off!
What is the empiric treatment for native vertebral osteomyelitis?
Ceftriaxone + Vancomycin
How would you treat arthritis caused by Lyme disease?
Doxycycline x 28 days
Which patients with a tick bite would you treat empirically for Lyme disease?
If all 3 criteria are met:
(1) Confirmed Ixodes species
(2) Highly endemic area
(3) Tick attached for > 36 hours
What is the treatment for a high risk tick bite if you are concerned about Lyme disease?
Doxycycline 200 mg PO x 1 dose within 72 hours of tick removal
What is the treatment for erythema migrans with a target lesion at the site of a tick bite?
Doxycycline x 10 days
What are three options for treatment of an animal bite infection?
(1) Amoxicillin-clavulanic acid
(2) Cephalosporin (2nd or 3rd) + Metronidazole
(3) Moxifloxacin
What would you treat an infection related to a human bite with?
(1) Amoxicillin-Clavulanic Acid
(2) 2nd or 3rd Gen Cephalosporin + Flagyl
(3) Moxifloxacin
