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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
What is the empirical treatment for Hematogenous Osteomyelitis for IVDU?
Vancomycin + Ceftazidime (to cover pseudomonas)
26
Pathogen directed therapy: | MSSA
Clox or Cefazolin
27
Pathogen directed therapy: | MSSA (for a severe B lactam allergy) ?
Vancomycin or Clinda
28
Pathogen directed therapy: | MRSA
Vancomycin
29
Pathogen directed therapy: | MRSA for B lactam allergy
- Dapto - Linezolid (bacteriostatic) - Clindamycin
30
Pathogen directed therapy: | S. agalactiae (group B strep)
Pen G or Cefazolin
31
Pathogen directed therapy: | S. agalactiae (group B strep) for severe beta lactam allergy?
Vanco
32
Pathogen directed therapy: | E. coli
Ceftriaxone | or Cipro/Levo for Severe B lactam allergy
33
Pathogen directed therapy: | H. influenza
Cefuroxime (if susceptible) or Ceftriaxone
34
Pathogen directed therapy: | H. influenza for severe B lactam allergy
Cipro/Levo
35
Pathogen directed therapy: | P. aeruginosa
Ceftazidime
36
Pathogen directed therapy: | P. aeruginosa for severe B lactam allergy ?
Cipro/Levo
37
What is appropriate empirical treatment for: | Gram positive cocci in clumps
-prob staph So Cloxacillin ?
38
What is appropriate empirical treatment for: | Gram negative bacilli
Amoxicillin ?
39
What are considerations for step down therapy for staphylococcal osteomyelitis?
- 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
What are the options for oral antimicrobial therapy for Hematogenous Osteomyelitis?
- Cloxacillin - concerns regarding ability to achieve adequate concentrations in bone - Cephalexin - Clindamycin
41
Typical response for acute therapy for Hematogenous Osteomyelitis
-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
Duration of therapy for Hematogenous Osteomyelitis
4-6 weeks (4 weeks for children, 6 weeks for vertebral osteomyelitis) *shorter for kids bc they respond better
43
What is the role of rifampin in treating osteomyelitis ?
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
Is Rifampin cidal or static?
cidal
45
Is rifampin ever given as mono therapy ?
No - leads to resistance but in combination, increases activity in biofilm and may prevent resistance to other agent
46
Adverse effects of Rifampin?
- hepatotoxicity with elevated LFTs - hepatitis with necrosis/cholestasis - hypersensitivities - gastritis - orange-red saliva, urine and tears
47
Describe the drug interactions that occur with Rifampin ?
Induces CYP 2C9 and PgP | -increases metabolism of many drugs
48
What is Contiguous-spread Osteomyelitis ?
Anything that is proximal to the bone and then results in osteomyelitis -Could start as a DFI, foot ulcer, or trauma for example.
49
Neutrophils should not be over ____%
- Shouldn't be over 70% | - If it's over 80% then it usually means bacterial infection
50
Contiguous-spread Osteomyelitis: | Most common pathogen
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
What are our 1st two options for Contiguous-spread Osteomyelitis? How do you decide between them?
Pip-tazo +/- Vancomycin or Ertapenem/Meropenem +/- Vancomycin *you want to save Carbapenems if possible
52
How would you treat Contiguous-spread Osteomyelitis if you need anaerobic coverage as well ?
Ceftriax + Vanco +/- Metro Ceftazidime + Vanco +/- Metro
53
How would you treat Contiguous-spread Osteomyelitis for severe B lactam allergy ?
Cipro/Levo/Moxi + Vanco
54
Are rashes with amoxicillin common?
Yes
55
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 ?
mild rash is not a CI to receiving another penicillin
56
If pt one year ago had hives on day 2 of therapy, what do you recommend to treat Contiguous-spread Osteomyelitis?
This is an actual B lactam allergy !! THEREFORE, Quinolone + Vanco ( to cover S. aureus) + Metro (to cover B. fragilis)
57
What is the typical response to Contiguous-spread Osteomyelitis
variable
58
What is the duration of treatment for Contiguous-spread Osteomyelitis
>4-6 weeks including >2 weeks of effective IV therapy 10 days IV therapy in children with pseudomonas osteochondritis (puncture wound)
59
Epidemiology of Infectious Arthritis ?
- children < 16 years - adults 18-30 (gonococcal, GC) - adults > 50
60
Infectious Arthritis: | Hematogenous spread most often to ?
knee (>50% of cases) and hip joints
61
Infectious Arthritis: | Most common pathogen?
S. aureus (50% of cases)
62
Infectious Arthritis: | ___________ in 10-20% especially in children <5 years old
Streptococcus
63
Infectious Arthritis: | ______ _______ in 50% of adult cases 18-30 years old
Neisseria gonorrhoea
64
Infectious Arthritis: | __________________ if joint trauma, IVDU, neonates, advanced age, immunocompromised
GNB including P. aeruginosa
65
Infectious Arthritis: | Risk factors ?
- neonates, advanced age - arthritis, joint trauma, prior intra-articular injection, prosthetic joint - bacteremia (intravascular or indwelling catheter, IVDU), diabetes, immunocompromised
66
Infectious Arthritis: | What are some signs and symptoms?
- 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
Infectious Arthritis: | In addition to symptoms, how is IA diagnosed?
- 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
Are bone or joint infections spread more rapidly?
Joint infections are rapidly spread bc the tissue is softer
69
Describe the approach to treating Infectious Arthritis
- 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
Infectious Arthritis: | Treatment targeting MSSA
Clox or Cefazolin
71
Infectious Arthritis: | Treatment targeting MSSA (severe B lactam allergy)
Vanco
72
Infectious Arthritis: | Treatment for MRSA
Vancomycin | [Linez or Dapto]
73
Infectious Arthritis: | Treatment targeting Streptococcus
Pen G
74
Infectious Arthritis: | Treatment targeting Streptococcus (severe B lactam allergy)
Cefazolin, Vanco or Clinda
75
Infectious Arthritis: | Treatment targeting N. gonorrhea
Ceftriaxone (1 g IV/IM q24h x 7 days) + Azithro (1 g PO x 1 dose)
76
Infectious Arthritis: | Treatment targeting P. aeruginosa
Ceftazidime *consider initial combination therapy with 2 anti-pseudomonas (ex. B lactam + Cipro/Levo or Gent/Tobramycin)
77
Infectious Arthritis: | Treatment targeting P. aeruginosa (severe B lactam allergy)
Cipro/Levo
78
Infectious Arthritis: | Typical Response ?
- clinical and laboratory improvement within 3-4 days - repeat radiograph at 2-3 weeks to rule out osteomyelitis - complications in 20% of cases
79
Infectious Arthritis: | Duration for S. aureus and GNB infections
3-4 weeks including >1-2 weeks of IV therapy
80
Infectious Arthritis: | Duration for streptococcal infections
2-3 weeks including >1-2 weeks of IV therapy
81
Infectious Arthritis: | Duration for gonococcal infections
1-2 weeks

Clinical 2 - Antibiotics (14 decks)

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