SSTIs

Question 1

Cat bites

• epidemiology (how many get infected)
• etiology
• management

Answer 1

• 80% of cat bites get infected
• Pastuerella multocida most common but POLYMICROBIAL
• Treat empirically with amoxil-clav

Question 2

Dog bites

• epidemiology (how many get infected)
• etiology
• management

Answer 2

• 5% of dog bites get infected
• Pastuerella canis most common but POLYMICROBIAL
• Treat only if severe or immune-compromised host with amoxil-clav

Question 3

Human bites

-etiology

Answer 3

POLYMICROBIAL
Viridens strep
Staph epidermidis
Corynebacterium
S. aureus
Bacteroides
Peptostreptococcus

Question 4

Clenched fist injury

• epidemiology (how many get infected)
• etiology

Answer 4

• high risk of infection
• patients present late
• POLYMICROBIAL

Question 5

Other animal bites

-general considerations

Answer 5

• Tetanus vaccine booster or IgG if never vaccinated

- Rabies vaccine and IgG

Question 6

Cat scratch disease

• epidemiology (who gets it)
• etiology
• clinical presentation
• diagnosis
• Treatment

Answer 6

• children and young adults
• Bartonella henselae
• local LAD +/- cutaneous lesion but can be atypical
• serology, blood culture
• Azithromycin

Question 7

Disseminated gonococcal infection

-2 classic clinical presentations

Answer 7

-Triad of tenosynovitis, polyarthritis, dermatitis
OR
-purulent arthritis

Question 8

Infectious lymphadenopathy

-etiology

Answer 8

Viral: HIV, CMV, EBV
Bacterial: GAS, S. aureus, Bartonella henselae and many others
Mycobacteria: TB and atypical
Parasite: toxoplasma, histoplasma
Fungal: Sporotrichosis

Question 9

Septic arthritis

-etiology

Answer 9

• disseminated gonoccocal infection
• staph aureus
• strep
• G(-)
• TB
• Fungal

Question 10

Septic arthritis

-risk factors

Answer 10

• Age > 80
• diabetes
• pre-existing joint disease
• recent surgery/injection
• prosthetic joint
• IVDU

Question 11

Septic arthritis

-clinical presentation

Answer 11

Triad: fever, pain (cannot bear weight), decreased range of motion

Question 12

Septic arthritis

-diagnosis

Answer 12

• aspirate synovial fluid and Gram stain and C&S
• blood cultures
• Xray to rule out osteomyelitis

Question 13

Septic arthritis

-management

Answer 13

• antibiotics based on C&S

- aspire fluid/ surgical drainage

Question 14

Septic arthritis

-how does the infective agent get there

Answer 14

hematogenous> trauma >post-surgery > from osteomyelitis

Question 15

Disseminated gonococcal infection

-diagnosis

Answer 15

• cervical/urethral swab usually +

- blood, skin, synovial culture can be -

Question 16

Disseminated gonococcal infection

-management

Answer 16

• Cefotaxime+ Doxyxline
• aspirate fluid
• treat partners

Question 17

Ludwig’s angina

-definition

Answer 17

-cellulitis of bilateral sublingual/submandibular spaces

Question 18

Ludwig’s angina

-risk factors

Answer 18

• recent dental work
• tooth pain
• immune compromise
• tongue piercing
• mandibular fracture

almost always the result of an oral infection

Question 19

Ludwig’s angina

-etiology in immunecompetent and immunocompromised

Answer 19

POLYMICROBIAL

Immunecompetent: strep, G+ anaerobes, bacteroides

Immunocompromised: pseudomonas, clostridium, candida

Question 20

Ludwig’s angina

-management

Answer 20

• monitor airway (1/3 require intubation)

- Antibiotics IV (e.g penicillin+clindamycin+metronidazole)

Question 21

Non-bullous impetigo

-clinical presentation

Answer 21

• bilateral skin lesions that are painless and pruritic

- bumps–>blisters–>golden crust

Question 22

Non-bullous impetigo

-etiology

Answer 22

-Staph aureus, often preceded by URTI

Question 23

Non-bullous impetigo

-epidemiology (who gets it)

Answer 23

-school-aged children

Question 24

Non-bullous impetigo

-treatment

Answer 24

Topical antibiotic (Mupirocin)

Question 25

Bullous impetigo - epidemiology (who gets it) - etiology

Answer 25

- Neonates>> children> adults | - Toxin producing S. aureus

Question 26

Bullous impetigo | -diagnosis in neonate

Answer 26

-blood cultures and septic evaluation

Question 27

Bullous impetigo | -management (treatment and complications)

Answer 27

- cloxacillin or vancomycin (if MRSA) Complications: dehydration +/- sepsis

Question 28

Diabetic foot infection | -2 factors that contribute to diabetic foot infection

Answer 28

1) peripheral neuropathy | 2) decreased blood flow (macro and microvascular)--> decreased immune system

Question 29

Diabetic foot infection | - patient assessment

Answer 29

1) The whole patient: systemic illiness? social support? comorbidities? 2) The affected limb: problems that will impair healing (e.g. charcot joint, vascular disease)? 3) The infection: is it there? how severe?

Question 30

Diabetic foot infection | -how to quantify peripheral vascular disease

Answer 30

- use (ankle/brachial) blood pressure

Question 31

Diabetic foot infection | -risk factors

Answer 31

- previous amputation - wound extending to the bone - peripheral vascular disease Are the top three.

Question 32

Diabetic foot infection | -how to determine presence and severity of infection

Answer 32

- Presence: inflammation +/- purulent discharge | - Severity: IDSA criteria (grade 1-4)

Question 33

Diabetic foot infection | -management

Answer 33

1) imaging if required 2) wound culture if pt has recently received ab 3) Ab for infected wounds: usually can just cover staph and strep (e.g. cloxacillin). This changes if risk of MRSA, or pt has received ab recently or pseudomonas risk factors 4) good wound care: cleaning, elevation

Question 34

Cellulitis - how it happens - etiology

Answer 34

- break in skin allows normal flora to invade dermis and subcutaneous tissue - almost always staph and strep

Question 35

Cellulitis | -clinical presentation

Answer 35

Localized: erythema, LAD, lymphangitis Systemic: bullae, sever swelling, hemorrhage, systemic symptoms

Question 36

Cellulitis | -management

Answer 36

- empiric Ab based on presentation - elevate - analgesic - draw a line around cellulitis

Question 37

Erisypelas - what is it? - what causes it?

Answer 37

- Infection limited to upper dermis and superficial lymphatics (cellulitis is deeper) - almost always B-hemolytic strep

Question 38

Erisypelas - clinical presentation - management

Answer 38

Clinical presentation: well-demarcated, raised erythema, rapid onset, fever Management: Penicillin V or Amoxil

Question 39

Necrotizing fasciitis - what is it? - what types? - etiology of each type - which type is more common?

Answer 39

- Deep infection of subcutaneous tissue, sever destruction of fat and fascia - Type 1: immunocompromised/post-operative (Polymicrobial) - Type 2: healthy individuals (GAS) **Type 1 is far more common**

Question 40

Necrotizing fasciitis | -clinical presentation

Answer 40

- bullae - disproportionate pain - swelling - erythema - systemic signs (fever, tachycardia, hypotension) - rapidly progressing

Question 41

Necrotizing fasciitis | -management

Answer 41

- IMMEDIATE surgical consult - Cultures of deep tissue (surgical) and blood - IMMEDIATE antibiotics: piperacillin-tazo +metronidazole or clindamycin+ carbapenem+cefepime (cover everything)

Question 42

Osteomyelitis - what is it? - possible etiology - management (in Vancouver)

Answer 42

Definition: infection of the bone or bone marrow Etiology: extrapulmonary TB, staph aureus Management: - Imaging - Blood cultures - Surgical debridement and bone cultures - Ab based on bone culture - Check for endocarditis