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Flashcards in SSTs (4) Deck (77):
1

list the SST/joint infections we are expected to know

1. animal bites
2. infectious lymphadenitis
3. septic arthritis
4. disseminated gonococcal infection
5. deep space infections (Ludwig's angina)
6. superficial skin infections (impetigo, scalded skin)
7. diabetic foot
8. cellulitis/erisypelas
9. necrotizing fasciitis
10. osteomyelitis

2

what % of cat bites get infected

80%

3

what is the etiologic agent most common in infected cat bites

Pasteurella multocida

4

what type of infections result from cat bites

deep space
bone
joint

these types are more likely with cat bites

5

Tx for cat bites

empiric = amoxicillin-clavulanate

6

what % of dog bites get infected

5%

7

what is the etiologic agent in infected dog bites

Pasteurella canis

8

Tx for infected dog bites

treat only if bite is severe or pts is immunocompromised

amoxicillin-clavulanate

9

what is the etiologic agent in cat scratch disease

Bartonella henselae

(cats are natural reservoir)

10

what is the etiologic agent in infected human bites

polymicrobial

1. STREP VIRIDANS (100%)
2. bacteroides (82%)
3. S. epidermis (53%)
4. corynebacterium
5. S. aureus
6. Peptostreptococcus
7. Eikenella

11

what is "clenched fist injury"

"reverse bite"

very high risk of infection

risk of septic joint and osteomyelitis

administer IV Ab and imaging

12

Tx for human bite infections

either amoxicillin-clavulanate or pipercillin-tazobacter (because has coverage for pseudomonas)

13

what two other diseases should you consider in a patient with a bite wound

tetanus

rabies (i.e bats)

14

what is another name for infectious lymphadenitis

cat scratch disease

(Bartonella henselae)

15

clinical presentation of cat scratch disease/infectious lymphadenitis

local lymphadenitis with or without cutaneous lesion

skin lesion shows several days after exposure and lasts 1-3 weeks

10% = atypical--> liver, spleen, ocular, neuro, MSK, FUO involvement

16

Tx for cat scratch disease

azithromycin

17

other than cat scratch disease, other etiologies of infectious lymphadenitis

1. GAS
2. S. aureus
3. toxoplasma
4. viral: HIV, CMV, EBV
5. mycobacteria
6. sporotrichosis, histoplasma, francisella, bacillus anthracis, borellia burgdorferi, yersenia pestis, hocardia

18

risk factors for septic arthritis

1. older than 80
2. diabetes
3. pre-existing joint disease
4. recent joint surgery or infection
5. prosthetic joint
6. IVDU

19

etiologic agents in septic arthritis

S. AUREUS

S. aureus>>strep>gram -orgs/TB/fungal

20

how do you diagnose septic arthritis

arthrocentesis (synovial fluid analysis)

gram stain/culture
blood culture
xray to rule out osteomyelitis

21

if septic arthritis is due to S. aureus, how is it treated

remove joint

22

what is disseminated gonoccoccal infection

a type of septic arthritis

23

clinical presentation of disseminated gonococcal infection

2 classic syndromes
1. triad of tenosynovitis, polyarthritis and dermatitis
2. purulent arthritis

24

Tx of disseminated gonococcal infection

ceftriaxone and doxycycline

doxy covers chlamydia (most people need both)

if purulent arthritis, IV therapy with joint aspiration

25

where do deep space infections arise from

progression of an oral infection

26

what is Ludwig's angina

deep space infection

cellulitis of bilateral sublingual/submandibular spaces

27

risk factors for Ludwig's angina

1. immune compromised
2. tongue piercing
3. mandibular fracture


almost always results from oral infection (2nd and 3rd molars are most common)

28

etiologic agents for Ludwig's angina

strep and anaerobes (gram +)

can also be bacteroides

29

clinical presentation of deep space infection/Ludwig's angina

swollen neck
difficulty opening mouth, swallowing
fever and malaise

30

Tx for deep space infections

monitor and protect airway (1/3 patients require intubation)

antibiotics: penicillin G OR clindamycin + metronidazole

surgical evaluation
CT to assess size and spread

31

what type of infections are superficial skin infections

toxin mediated skin damage

32

etiological agent for scalded skin syndrome

S. aureus

33

classical presentation of scalded skin syndrome

NIKOLSKYS SIGN

reddened skin
fluid collects underneath
skin rubs off leaving red base

34

diagnosis of scalded skin syndrome

clinical

35

Tx scalded skin syndrome

symptomatic

usually vancomycin if need Abs

36

2 types of impetigo

bullous
non-bullous

37

which type of impetigo is highly contagious and is seen in school aged kids?

which type is seen in neonates?

non bullous = highly infectious and seen in school aged kids

bullous = seen often in neonates

38

etiologic agent of non bullous impetigo

S. aureus

also GAS

39

etiologic agent of bullous impetigo

TOXIN producing S. aureus
exfoliative toxin A and B

40

diagnosis of impetigo

clinical

(for bullous may have cultures, septic eval)

41

Tx nonbullous impetigo

topical antibiotic--MUPIROCIN
PO--cloxacillin
cephalosporins

42

Tx bullous impetigo

oral or IV Ab
cloxacillin
cephalosporin
vancomycin is MRSA suspected

43

what type of infection is diabetic foot

peripheral vascular disease related soft tissue infection

44

diabetic food risk factors

previous amputation
wound extending to bone
peripheral vascular disease
ulcer duration > 30 days
loss of sensation
Hx of recurring ulcers
wound caused by trauma

40% of infected people have peripheral vascular disease

45

etiologic agents in
1. mild
2. moderate
3. severe
diabetic foot

1. S. aureus (MSSA), streptococcus
2. S. aureus (MSSA), streptococcus
3. assume everything

46

how do you assess diabetic foot

"assess at 3 levels"

1. whole patients-->signs of systemic illness, social support
2. affected limb/foot--> problems impairing healing, peripheral vascular disease
3. infection--> is an infection present? how severe? hospitalize all patients with a severe infection or moderate infection with low social support or failing outpatient management

surgery consult if suspect deep space infection or necrotizing fasciitis

47

how do you correctly culture a diabetic foot infection

1. clean and debride the wound
2. scrape or biopsy the ulcer base
3. aspirate purulent secretions --> never swab an uninfected wound or a dirty infected wound
4. send for gram stain, aerobic and anaerobic culture

48

Tx for diabetic foot infection

majority of mild and moderate cases can be treated with Abs that cover staph and strep

ALL infected wounds should have Abs

CLOXACILLIN (choice) or 1st generaton cephalosporin

if you think high risk for MRSA give empiric MRSA coverage

49

what is cellulitis

infection of the deep dermis and subcutaneous fat

50

how does cellulitis happen

break in skin allowing normal skin flora or exogenous flora to invade dermis and subcutaneous tissue

51

epidemiology of cellulitis

diabetics
peripheral vascular disease

52

etiologic agent of cellulitis

almost always strep or staph

53

clinical presentation of cellulitis

simple, localized cellulitis--> no fever/other systemic symptoms; WBC normal; lymphademopathy and lymphangitis

severe cellulitis--> systemic symptoms, bullae, hemorrhage, severe swelling

54

how do you monitor the progression of suspected cellulitis

infection spreads rapidly... draw a line around the infected area's borders to monitor spread

55

Tx for cellulitis

empiric Abs
elevate
analgesics

56

what is erisypelas

infection limited to upper dermis and superficial lymphatics

57

what causes erisypelas

almost always B hemolytic strep (i.e GAS/S pyogenes)

58

clinical presentation of erisypelas

sharp, raised, well demarcated edema

rapid onset

fever and signs of systemic toxicity

59

Tx of erisypelas

mild/moderate = outpatient --> penicillin or amoxicillin

severe = admit to hospital --> IV benzathine penicillin G

60

what type of infection is necrotizing fasciitis

rapidly progressive soft tissue infection

61

where does necrotizing fasciitis infect

deep infection of the subcutaneous tissue causing severe destruction of fat and fascia

62

etiologic agent of
1. type 1
2. type 2
necrotizing fasciitis

1. immunocompromised or post operation patients--> POLYMICROBIAL

2. healthy individuals of any age --> GROUP A STREP (GAS) aka Beta hemolytic strep

63

clinical presentation of necrotizing fasciitis

Skin:
bullae
disproportionate pain
swelling
erythema
crepitus
(gangrene)

systemic:
fever
tachycardia
hypotension

64

how do you test for necrotizing fasciitis

deep tissue cultures during debridement

65

Tx of necrotizing fasciitis

IMMEDIATE SURGICAL CONSULT

IV Abs-->
Type 1: piperacillin-tazobactam and metronidazole -OR- clindamycin
(also carbapenems + vanco?) (for polymicrobial)

Type 2: clindamycin and penicillin G (for GAS)

66

what is osteomyelitis

inflammation or infection of the bone or bone marrow

67

what causes osteomyelitis

depends on the route of infection and patients characteristics

IVDU in vancouver--> S. aureus (MRSA)

otherwise if its spinal osteomyelitis its likely TB

68

how do you diagnose osteomyelitis

CT

69

Tx for osteomyelitis

1. for IVDU--> debridement and bone culture in the OR; Ab = VANCO (+ screen for endocarditis)

2. for spinal osteomyelitis (due to TB)--> TB TX for 12 months

70

what do all bite injuries need to be assessed for

tetanus and rabies risk

71

septic arthritis is _____ spread and the most common organism is _____

hematogenously

S. aureus

72

what is the most reliable way to test for disseminated gonococcal infection

cervical or urethral swab

73

what organism do cat and dog bites usually contain? what should they be treated with?

pasteurella

amoxicillin-clavulanate

74

what SST infection is a surgical emergency

necrotizing fasciitis

75

non-bullous impetigo is usually caused by ____ and can be treated with _____

S. aureus

topical or oral Abs

76

bullous impetigo is usually caused by ____ and can be especially severe in _____

S. aureus TOXIN

neonates

77

what increases the risk of infection in diabetics

1. impaired sensation
2. impaired healing
3. frequent peripheral vascular disease