Bone/Joint/Skin/Soft-Tissue Infections Flashcards
Folliculitis. What is it and how to treat?
Inflamed hair follicle. Topical agent for 7 days.
Carbuncle/Furuncle: What is it and how to treat
> 1 cm lesion that extends beyond hair shaft. I&D may be enough. May need an oral agent for 5-7 days.
Impetigo: What is it and how to treat
Superficial. Common on face in peds. Highly contagious. Topical mupirocin BID for 5 days. PO agent for 7 days if multiple lesions. Don’t use Bactrim due to lack of GAS activiy.
Cellulitis: What is it and how to treat
Acutely spreading, skin infection (epidermis, dermis, and subcutaneous). PO if SIRS 0-1. IV if SIRS >1. Treat for 5-14 days.
Nectrotizing Fascitis: What is it and how to treat
Acute, often rapidly spreading infection in the fascia, subcutaneous fat, or muscle. Wooden-hard induration. Braod spectrum IV abx until definitive therapy via C&S.
Pyomyositis: what is it and how to treat.
Pain, tenderness, edema overlying a major muscle. Empirical treatment with vancomycin (90% of cases are Staphylococcus)
What are the SIRS criteria?
T > 38 or <36
HR > 90
RR > 20
WBC > 12k or < 4k
*Systemic Inflammatory Response Syndrome.
What causes Cat Scratch disease and how to treat?
Bartonella henselae: macrolides or doxy
Nectrotizing toxic shock: Cause and treatment
Streptococcus pyogenes: Penicillin + clindamycin
Necrotizing, gas gangrene: Cause and treatment
Clostridium perfringens: Penicillin + clindamycin
Bubonic plague: Cause and treatment
Yersinia pestis: Streptomycin (may substitute gentamicin) or Doxycycline
Which candida are fluconazole resistant and what do you treat with?
C. krusei and C. glabrata have fluconazole resistance. Echinocandin.
What’s first line for aspergillus (fungus) infxn
voriconazole is first line, duration 6-12 weeks
________ is shown to suppress toxin and cytokine production in clostridial and streptococcal infections
Clindamycin
First line preop prophy?
Anceft: 2 grams within 30 minutes of cut time (3 grams if > 120 kg).
Preop prophy: What if BL allergy?
Vanco (15 mg/kg within 1 hr) or clinda
What’s the preop dose for gent?
5 mg/kg
_______ should be added in addition to cefazolin for surgeries where anaerobic pathogens are a concern
Metronidazole: Biliary tract, appendectomy, colorectal, clean-contaminated procedures associated with head and neck or urologic tract
When do redose intraop prophy abx?
After 2 half-lives
How long should you give surgical prophy?
Less than 24 hours.
How should you treat a surgical site infection with no systemic signs?
I&D is usually sufficient
What systemic sign of infection warrant treatment of a surgical site infection?
T > 38.5 (high fever!)
WBC > 12k
HR > 110 (higher than the SIRS criteria)
> 5 cm erythema or induration
How long to treat surgical site infection that shows systemic signs?
24-48 hours. Use the same types of ABX as preop.
Is an actively draining sinus tract or purulence communicating directly with the prosthesis enough to diagnose a PJI (prosthetic joint infection)?
Yes, that alone is enough.
When is a PJI considered Early?
1-3 months after implantation
PJI = prosthetic joint infection
What two factors determine the treatment and duration of PJI’s?
Whether hardware was retained or not. And Staph vs non-staph offending organism
Are all staphylcocci biofilm producers (in PJI’s)?
Yes, yes they are. Harder to treat.
What is DAIR?
Debridement and Implant Retention (talking about PJI’s)
How long to treat staph PJI if DAIR or 1 stage exchange?
Induction with 2-6 weeks of IV abx + rifampin followed by PO (keflex or dicloxacillin) QS to 3 months (unless knee and DAIR, then 6 months).
Follow that with indefinite suppression.
How to treat Staph PJI if 2 stage or permanent removal
4-6 weeks of IV or PO abx (no rifampin).
How to treat non-staph PJI?
No induction phase with IV abx is required. 4-6 weeks total therapy with either IV or highly bioavailable PO. Regardless of DAIR vs 1 stage exchange vs 2 stage vs removal.
- DAIR and 1 stage: follow-up with indefinite PO suppression
- Amputation: 24-48 hours total therapy.
How long to treat PJI if ampuation?
24-48 hours only. Regardless if staph or non-staph.
How important is bone abx penetration?
Not that important. Pay more attention to clinical cure rates. Don’t get distracted by that.
What is the role of rifampin in osteomyelitis and joint infections?
For staph only. Always in combination with another agent. It aids in penetrating staph biofilm.
What agents are commonly used for long-term suppression in PJI when hardware is retained?
FQ +/- RIF
Doxy
TMP/SMX
What is Vancomycin Mech of Action?
Cell wall synthesis inhibitor. Binds to alanine termini of PG chains preventing crosslinking. It is bactericidal usually, but against staph, it’s mostly static.
What infections is ceftaroline currently approved to treat?
CAP and SSTI’s: 600 mg IV q8-12h
What are some potential complications of Linezolid therapy?
Bone marrow suppression
Neuropathies (peripheral, optical)
Serotonin stuff (not as bas as once thought)
What is tedizolid?
A newer oxazolidinone with activity against linezolid-resistant strains, once-daily dosing, and fewer adverse effects and serotonergic drug interactions
What is Oritivancin and Dalbavancin?
New vancomycin alternatives. Can give just one dose for Skin infections. Not recommended for bone infections.
What’s the deal with Omadacycline?
A new broad-spectrum tetracycline approved for SSTI’s. Has MRSA activity along with other stuff. Oral dosing requires 4 hours fasting! Take with water, then wait 2 hours before any food or drink (4 hours for dairy). Due to sequestration by divalent cations.
Duration of therapy for diabetic foot infections?
Depends on depth and what’s been removed:
SSTI only: 2-5 days
Osteo but infected bone resected and only SSTI remains: 1-3 weeks
Osteo and not all infected bone resected: 4-6 weeks
Define Mild, moderate, and severe diabetic foot infections:
Mild: No systemic symptoms, skin and soft tissue, < 2 cm erythema
Moderate: Local, but deeper tissues (abcess, osteo). > 2 cm erythema. < 2 SIRS criteria (systemic sx)
Severe: Deep tissues. 2 or more SIRS criteria.
What is the most common pathogen for Native Vertebral Osteomyelitis (NVO)?
Staph Aureus. It’s hematogenous.
How long to treat Native Vertebral Osteo
6 weeks. Easy! IV or PO
