Bone/Joint/Skin/Soft-Tissue Infections

Question 1

Folliculitis. What is it and how to treat?

Answer 1

Inflamed hair follicle. Topical agent for 7 days.

Question 2

Carbuncle/Furuncle: What is it and how to treat

Answer 2

> 1 cm lesion that extends beyond hair shaft. I&D may be enough. May need an oral agent for 5-7 days.

Question 3

Impetigo: What is it and how to treat

Answer 3

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.

Question 4

Cellulitis: What is it and how to treat

Answer 4

Acutely spreading, skin infection (epidermis, dermis, and subcutaneous). PO if SIRS 0-1. IV if SIRS >1. Treat for 5-14 days.

Question 5

Nectrotizing Fascitis: What is it and how to treat

Answer 5

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.

Question 6

Pyomyositis: what is it and how to treat.

Answer 6

Pain, tenderness, edema overlying a major muscle. Empirical treatment with vancomycin (90% of cases are Staphylococcus)

Question 7

What are the SIRS criteria?

Answer 7

T > 38 or <36
HR > 90
RR > 20
WBC > 12k or < 4k

*Systemic Inflammatory Response Syndrome.

Question 8

What causes Cat Scratch disease and how to treat?

Answer 8

Bartonella henselae: macrolides or doxy

Question 9

Nectrotizing toxic shock: Cause and treatment

Answer 9

Streptococcus pyogenes: Penicillin + clindamycin

Question 10

Necrotizing, gas gangrene: Cause and treatment

Answer 10

Clostridium perfringens: Penicillin + clindamycin

Question 11

Bubonic plague: Cause and treatment

Answer 11

Yersinia pestis: Streptomycin (may substitute gentamicin) or Doxycycline

Question 12

Which candida are fluconazole resistant and what do you treat with?

Answer 12

C. krusei and C. glabrata have fluconazole resistance. Echinocandin.

Question 13

What’s first line for aspergillus (fungus) infxn

Answer 13

voriconazole is first line, duration 6-12 weeks

Question 14

________ is shown to suppress toxin and cytokine production in clostridial and streptococcal infections

Answer 14

Clindamycin

Question 15

First line preop prophy?

Answer 15

Anceft: 2 grams within 30 minutes of cut time (3 grams if > 120 kg).

Question 16

Preop prophy: What if BL allergy?

Answer 16

Vanco (15 mg/kg within 1 hr) or clinda

Question 17

What’s the preop dose for gent?

Answer 17

5 mg/kg

Question 18

_______ should be added in addition to cefazolin for surgeries where anaerobic pathogens are a concern

Answer 18

Metronidazole: Biliary tract, appendectomy, colorectal, clean-contaminated procedures associated with head and neck or urologic tract

Question 19

When do redose intraop prophy abx?

Answer 19

After 2 half-lives

Question 20

How long should you give surgical prophy?

Answer 20

Less than 24 hours.

Question 21

How should you treat a surgical site infection with no systemic signs?

Answer 21

I&D is usually sufficient

Question 22

What systemic sign of infection warrant treatment of a surgical site infection?

Answer 22

T > 38.5 (high fever!)
WBC > 12k
HR > 110 (higher than the SIRS criteria)
> 5 cm erythema or induration

Question 23

How long to treat surgical site infection that shows systemic signs?

Answer 23

24-48 hours. Use the same types of ABX as preop.

Question 24

Is an actively draining sinus tract or purulence communicating directly with the prosthesis enough to diagnose a PJI (prosthetic joint infection)?

Answer 24

Yes, that alone is enough.

Question 25

When is a PJI considered Early?

Answer 25

1-3 months after implantation | PJI = prosthetic joint infection

Question 26

What two factors determine the treatment and duration of PJI's?

Answer 26

Whether hardware was retained or not. And Staph vs non-staph offending organism

Question 27

Are all staphylcocci biofilm producers (in PJI's)?

Answer 27

Yes, yes they are. Harder to treat.

Question 28

What is DAIR?

Answer 28

Debridement and Implant Retention (talking about PJI's)

Question 29

How long to treat staph PJI if DAIR or 1 stage exchange?

Answer 29

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.

Question 30

How to treat Staph PJI if 2 stage or permanent removal

Answer 30

4-6 weeks of IV or PO abx (no rifampin).

Question 31

How to treat non-staph PJI?

Answer 31

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.

Question 32

How long to treat PJI if ampuation?

Answer 32

24-48 hours only. Regardless if staph or non-staph.

Question 33

How important is bone abx penetration?

Answer 33

Not that important. Pay more attention to clinical cure rates. Don't get distracted by that.

Question 34

What is the role of rifampin in osteomyelitis and joint infections?

Answer 34

For staph only. Always in combination with another agent. It aids in penetrating staph biofilm.

Question 35

What agents are commonly used for long-term suppression in PJI when hardware is retained?

Answer 35

FQ +/- RIF Doxy TMP/SMX

Question 36

What is Vancomycin Mech of Action?

Answer 36

Cell wall synthesis inhibitor. Binds to alanine termini of PG chains preventing crosslinking. It is bactericidal usually, but against staph, it's mostly static.

Question 37

What infections is ceftaroline currently approved to treat?

Answer 37

CAP and SSTI's: 600 mg IV q8-12h

Question 38

What are some potential complications of Linezolid therapy?

Answer 38

Bone marrow suppression Neuropathies (peripheral, optical) Serotonin stuff (not as bas as once thought)

Question 39

What is tedizolid?

Answer 39

A newer oxazolidinone with activity against linezolid-resistant strains, once-daily dosing, and fewer adverse effects and serotonergic drug interactions

Question 40

What is Oritivancin and Dalbavancin?

Answer 40

New vancomycin alternatives. Can give just one dose for Skin infections. Not recommended for bone infections.

Question 41

What's the deal with Omadacycline?

Answer 41

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.

Question 42

Duration of therapy for diabetic foot infections?

Answer 42

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

Question 43

Define Mild, moderate, and severe diabetic foot infections:

Answer 43

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.

Question 44

What is the most common pathogen for Native Vertebral Osteomyelitis (NVO)?

Answer 44

Staph Aureus. It's hematogenous.

Question 45

How long to treat Native Vertebral Osteo

Answer 45

6 weeks. Easy! IV or PO