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Clinical 2 - Antibiotics > 4 - Bone & Joint Infections > Flashcards

4 - Bone & Joint Infections Flashcards

1
Q

What is hematogenous osteomyelitis?

A

pathogen gets into blood and then goes into the bone

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2
Q

Hematogenous Osteomyelitis:

85% of cases in what age group?

A

< 17 years old

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3
Q

Hematogenous Osteomyelitis:

Represents ___% of osteomyelitis in adults

A

20

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4
Q

Hematogenous Osteomyelitis:

Affects what bones typically?

A

typically long bones such as tibia, humerus and metaphysis of femur in children

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5
Q

Hematogenous Osteomyelitis:

What bones are affected in those > 50 yo or history of IVDU ?

A

more often lumbar and thoracic vertebrae

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6
Q

Hematogenous Osteomyelitis:

Most common pathogen ?

A

S. aureus

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7
Q

Hematogenous Osteomyelitis:

What pathogens are associated with those under 3 months old other than S. aureus?

A
  • Group B Streptococcus (S. agalactiae)

- Gram negative bacilli

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8
Q

Hematogenous Osteomyelitis:

What pathogens are associated with those under 5 years old other than S. aureus?

A
  • S. agalactiae
  • S. pneumoniae
  • H. influenzae (if not immunized fully)
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9
Q

Hematogenous Osteomyelitis:

What pathogens are associated with elderly other than S. aureus?

A

-GNB such as E. coli from urinary source

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10
Q

Hematogenous Osteomyelitis:

What pathogens are associated with IVDU other than S. aureus?

A

GNB including P. aeruginosa

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11
Q

Hematogenous Osteomyelitis:

What pathogens are associated with sickle cell disease ?

A

Salmonella

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12
Q

What types of ppl are at risk for S. pneumonia and H. influenza to be the cause of Hematogenous Osteomyelitis?

A

kids/ppl who have not been fully immunized

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13
Q

What are risk factors for adults getting Hematogenous Osteomyelitis?

A
  • over 50 years old
  • bacteremia (intravascular or indwelling catheter, IVDU)
  • co-existing infection
  • immunocompromised
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14
Q

What are the clinical signs and symptoms of osteomyelitis ?

A
  • acute pain, fever, other systemic signs of infection particularly in young and advanced age
  • indolent (causing little or no pain) presentation in adults particularly vertebral osteomyelitis
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15
Q

How is osteomyelitis diagnosed ?

A
  • radiograph show bone involvement after 10-14 days, bone scan via CT or MRI after 1 day
  • leukocytosis, elevated erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP)
  • positive culture in sub-periosteal pus/metaphysical fluid aspirates in 70%, positive culture in 50%
  • culture/susceptibility testing important for selecting antimicrobial therapy
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16
Q

What are the important principles of optimal antimicrobial therapy for osteomyelitis ?

A

a) prompt initiation
b) appropriate spectrum
c) bactericidal activity
d) high-dose, iv therapy to achieve adequate bone concentrations
e) prolonged duration

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17
Q

What is the 1st line for EMPIRICALLY treating hematogenous osteomyelitis in adults ? Why are they 1st line ?

A

Clox or Cefazolin (they cover strep and staph)

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18
Q

Why would you chose Vanco over Clox or Cefazolin ?

A

for MRSA coverage or severe beta lactam allergy

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19
Q

What does empirically treating mean?

A
  • you don’t know what the bug is, treating to target whatever possibilities the infection could be
  • BROAD
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20
Q

What is the empirical treatment for Hematogenous Osteomyelitis for those under 3 months old?

A

Cefotaxime + Vanco

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21
Q

Why don’t we use Ceftriaxone for those under 3 months?

A

AVOID CEFTRIAXONE IN NEONATES:

-risk of kernicterus

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22
Q

What is the empirical treatment for Hematogenous Osteomyelitis for those under 5 years old?

A

Cloxacillin or Cefazolin

(same as for adults?

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23
Q

What is the empirical treatment for Hematogenous Osteomyelitis for those under 5 years old if its MRSA ?

A

Vancomycin or Clinda for MRSA coverage

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24
Q

What is the empirical treatment for Hematogenous Osteomyelitis for elderly ?

A

Vancomycin + Ceftriaxone

bc they are risk of osteomyelitis in spine, often E. coli from urine

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25
Q

What is the empirical treatment for Hematogenous Osteomyelitis for IVDU?

A

Vancomycin + Ceftazidime (to cover pseudomonas)

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26
Q

Pathogen directed therapy:

MSSA

A

Clox or Cefazolin

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27
Q

Pathogen directed therapy:

MSSA (for a severe B lactam allergy) ?

A

Vancomycin or Clinda

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28
Q

Pathogen directed therapy:

MRSA

A

Vancomycin

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29
Q

Pathogen directed therapy:

MRSA for B lactam allergy

A
  • Dapto
  • Linezolid (bacteriostatic)
  • Clindamycin
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30
Q

Pathogen directed therapy:

S. agalactiae (group B strep)

A

Pen G or Cefazolin

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31
Q

Pathogen directed therapy:

S. agalactiae (group B strep) for severe beta lactam allergy?

A

Vanco

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32
Q

Pathogen directed therapy:

E. coli

A

Ceftriaxone

or Cipro/Levo for Severe B lactam allergy

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33
Q

Pathogen directed therapy:

H. influenza

A

Cefuroxime (if susceptible) or Ceftriaxone

34
Q

Pathogen directed therapy:

H. influenza for severe B lactam allergy

A

Cipro/Levo

35
Q

Pathogen directed therapy:

P. aeruginosa

A

Ceftazidime

36
Q

Pathogen directed therapy:

P. aeruginosa for severe B lactam allergy ?

A

Cipro/Levo

37
Q

What is appropriate empirical treatment for:

Gram positive cocci in clumps

A

-prob staph

So Cloxacillin ?

38
Q

What is appropriate empirical treatment for:

Gram negative bacilli

A

Amoxicillin ?

39
Q

What are considerations for step down therapy for staphylococcal osteomyelitis?

A
  • known pathogen and susceptibilities
  • adequate response to initial iv therapy of > 1 week for children or > 2 weeks for adults
  • suitable po option based on spectrum, bioavailability, tolerability
  • patient education, adherence and follow up
40
Q

What are the options for oral antimicrobial therapy for Hematogenous Osteomyelitis?

A
  • Cloxacillin - concerns regarding ability to achieve adequate concentrations in bone
  • Cephalexin
  • Clindamycin
41
Q

Typical response for acute therapy for Hematogenous Osteomyelitis

A

-clinical and laboratory improvement within 3-4 days, > 80% response rate within 7 days (CRP, followed by ESR then WBC), 30% recurrence rate in adults, 4-7% significant complications in children

42
Q

Duration of therapy for Hematogenous Osteomyelitis

A

4-6 weeks
(4 weeks for children, 6 weeks for vertebral osteomyelitis)

*shorter for kids bc they respond better

43
Q

What is the role of rifampin in treating osteomyelitis ?

A

Combination therapy particularly for infections involving BIOFILM (ex. S. aureus, CoNS infection of prosthetic joints, with agents such as Cipro/Levo, Clinda, Doxy, TMP-SMX, Linez

44
Q

Is Rifampin cidal or static?

A

cidal

45
Q

Is rifampin ever given as mono therapy ?

A

No - leads to resistance

but in combination, increases activity in biofilm and may prevent resistance to other agent

46
Q

Adverse effects of Rifampin?

A
  • hepatotoxicity with elevated LFTs
  • hepatitis with necrosis/cholestasis
  • hypersensitivities
  • gastritis
  • orange-red saliva, urine and tears
47
Q

Describe the drug interactions that occur with Rifampin ?

A

Induces CYP 2C9 and PgP

-increases metabolism of many drugs

48
Q

What is Contiguous-spread Osteomyelitis ?

A

Anything that is proximal to the bone and then results in osteomyelitis
-Could start as a DFI, foot ulcer, or trauma for example.

49
Q

Neutrophils should not be over ____%

A
  • Shouldn’t be over 70%

- If it’s over 80% then it usually means bacterial infection

50
Q

Contiguous-spread Osteomyelitis:

Most common pathogen

A

Mixed, polymicrobial infections with S. aureus or S. epidermis in 50-70% followed by streptococci, E. coli, P. aeruginosa and anaerobes such as B. fragilis (GI flora), Prevotella sp. (oral flora)

THEREFORE, we need BROAD treatment to target all of these possible bugs

51
Q

What are our 1st two options for Contiguous-spread Osteomyelitis? How do you decide between them?

A

Pip-tazo +/- Vancomycin
or
Ertapenem/Meropenem +/- Vancomycin

*you want to save Carbapenems if possible

52
Q

How would you treat Contiguous-spread Osteomyelitis if you need anaerobic coverage as well ?

A

Ceftriax + Vanco +/- Metro

Ceftazidime + Vanco +/- Metro

53
Q

How would you treat Contiguous-spread Osteomyelitis for severe B lactam allergy ?

A

Cipro/Levo/Moxi + Vanco

54
Q

Are rashes with amoxicillin common?

A

Yes

55
Q

If pt one year ago had itchy maculopapular rash on his upper arms and chest on day 7 of therapy - how do you treat Contiguous-spread Osteomyelitis ?

A

mild rash is not a CI to receiving another penicillin

56
Q

If pt one year ago had hives on day 2 of therapy, what do you recommend to treat Contiguous-spread Osteomyelitis?

A

This is an actual B lactam allergy !!
THEREFORE,
Quinolone + Vanco ( to cover S. aureus) + Metro (to cover B. fragilis)

57
Q

What is the typical response to Contiguous-spread Osteomyelitis

A

variable

58
Q

What is the duration of treatment for Contiguous-spread Osteomyelitis

A

> 4-6 weeks including >2 weeks of effective IV therapy

10 days IV therapy in children with pseudomonas osteochondritis (puncture wound)

59
Q

Epidemiology of Infectious Arthritis ?

A
  • children < 16 years
  • adults 18-30 (gonococcal, GC)
  • adults > 50
60
Q

Infectious Arthritis:

Hematogenous spread most often to ?

A

knee (>50% of cases) and hip joints

61
Q

Infectious Arthritis:

Most common pathogen?

A

S. aureus (50% of cases)

62
Q

Infectious Arthritis:

___________ in 10-20% especially in children <5 years old

A

Streptococcus

63
Q

Infectious Arthritis:

______ _______ in 50% of adult cases 18-30 years old

A

Neisseria gonorrhoea

64
Q

Infectious Arthritis:

__________________ if joint trauma, IVDU, neonates, advanced age, immunocompromised

A

GNB including P. aeruginosa

65
Q

Infectious Arthritis:

Risk factors ?

A
  • neonates, advanced age
  • arthritis, joint trauma, prior intra-articular injection, prosthetic joint
  • bacteremia (intravascular or indwelling catheter, IVDU), diabetes, immunocompromised
66
Q

Infectious Arthritis:

What are some signs and symptoms?

A
  • monoarticular, except polyarticular in gonococcal infections
  • pain, erythema, heat, swelling, effusion
  • fever (90%), elevated ESR and C-reactive protein (90%), leukocytosis (50%)
  • rash or bullies lesions in 70% of gonococcal infections
67
Q

Infectious Arthritis:

In addition to symptoms, how is IA diagnosed?

A
  • radiograph
  • synovial fluid aspirates show high leukocytes, high lactate and low glucose in non-gonococcal infection
  • positive gram stains in fluid in 50% of gonococcal and 25% of non-gonoccoal infections and positive cultures in 80% and 40% respectively
  • positive blood culture in 50% of non-gonococcal and 20% of gonococcal infections
68
Q

Are bone or joint infections spread more rapidly?

A

Joint infections are rapidly spread bc the tissue is softer

69
Q

Describe the approach to treating Infectious Arthritis

A
  • initial (daily) joint drainage particularly for hips and shoulders, joint rest followed by physical therapy
  • prompt, high dose, IV antimicrobial therapy, delay > 4-7 days associated with irreversible joint damage
  • options for empirical therapies similar to hematogenous osteomyelitis, with early pathogen-directed therapy based on Gram stain and culture/susceptibility testing
70
Q

Infectious Arthritis:

Treatment targeting MSSA

A

Clox or Cefazolin

71
Q

Infectious Arthritis:

Treatment targeting MSSA (severe B lactam allergy)

A

Vanco

72
Q

Infectious Arthritis:

Treatment for MRSA

A

Vancomycin

[Linez or Dapto]

73
Q

Infectious Arthritis:

Treatment targeting Streptococcus

A

Pen G

74
Q

Infectious Arthritis:

Treatment targeting Streptococcus (severe B lactam allergy)

A

Cefazolin, Vanco or Clinda

75
Q

Infectious Arthritis:

Treatment targeting N. gonorrhea

A

Ceftriaxone (1 g IV/IM q24h x 7 days) + Azithro (1 g PO x 1 dose)

76
Q

Infectious Arthritis:

Treatment targeting P. aeruginosa

A

Ceftazidime

*consider initial combination therapy with 2 anti-pseudomonas (ex. B lactam + Cipro/Levo or Gent/Tobramycin)

77
Q

Infectious Arthritis:

Treatment targeting P. aeruginosa (severe B lactam allergy)

A

Cipro/Levo

78
Q

Infectious Arthritis:

Typical Response ?

A
  • clinical and laboratory improvement within 3-4 days
  • repeat radiograph at 2-3 weeks to rule out osteomyelitis
  • complications in 20% of cases
79
Q

Infectious Arthritis:

Duration for S. aureus and GNB infections

A

3-4 weeks including >1-2 weeks of IV therapy

80
Q

Infectious Arthritis:

Duration for streptococcal infections

A

2-3 weeks including >1-2 weeks of IV therapy

81
Q

Infectious Arthritis:

Duration for gonococcal infections

A

1-2 weeks

Clinical 2 - Antibiotics (14 decks)

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