Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

CPS Statement Flash Cards > Management and diagnosis of osteoarticular infections > Flashcards

Management and diagnosis of osteoarticular infections Flashcards

1
Q

What is the incidence of hematogenous osteomyelitis?

A

1/100 000 children

- More frequent in young children

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What is the pathologic definition of osteomyelitis?

A

Inflammation of bone or bone marrow due to infection with microbial pathogen

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

How is chronic osteomyelitis defined?

A

Chronic osteomyelitis is defined with symptoms for more than 1 month in cases where avascular bone (sequestrum) alone or surrounded by new bone (involucrum) is present (Brodies’ abscess)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What is thought to be the most common “portal of entry” for bacteria in AO or SA?

A

Colonization of mucosal membranes of respiratory tract or through the skin

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

List 3 bacteria that are common colonizers of upper respiratory tract that may cause AO

A

Staph aureus
Strep pneumoniae
Strep pyogenes
Kingella kingae

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

In which population is there colonization rate of Kingella kingae?

A

Young children especially infants

Lower rates in older children

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What is the most common site of AO?

A

Metaphysis of long tubular bones ex: femur, tibia, or humerus

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What is the pathogenesis of AO?

A

At the metaphysis, the nutrient artery ends in small arterial loops that empty into venous sinusoids
Bacteria can translocate from the vessels into pooled blood at this site (possibly as a result of minor trauma), resulting in replication and suppuration
Bacterial toxins, inflammatory cytokines, ischemia and possibly the leukocytes themselves promote local bony destruction
When suppuration occurs in the metaphysis of bones, infection can extend to adjacent sub-periosteal areas and, later, to overlying soft tissues

*bacteria pools and causes infection

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Which population is at higher risk of septic arthritis occurring with acute osteomyelitis? What is the incidence of this?

A

Children <2 years of age
- Related to transphyseal vessels spreading infection and that the joint capsule extends beyond the epiphyseal plate in young children –> leads to easier spread

  • Based on MRI: 37% in children <2 years; only 17% in children over 10 years
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What is the clinical presentation of AO or SA in children/

A

Often presents with pseudo-paralysis (decreased movement or use of affected limb) or limping
- Pain may be the only symptom
+/- fever however presence of fever raises suspicion

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

How can AO or SA progress?

A

Can progress from the metaphysis to adjacent abscess at the periosteum and may progress to superficial changes of erythema and swelling of the skin
*should consider cellulitis and necrotizing fasciitis on the differential in these cases

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What are clinical features that would be specific to septic arthritis?

A

Specific joint swelling
Joint effusion
Pain on movement of the isolated joint

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

When do the features of AO and SA overlap?

A

Particularly during infections of the hip

Can be difficult to differentiate clinically

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What pathogen is associated with a more severe acute osteomyelitis or septic arthritis!

A

MRSA

- Kingella infections tend to be milder

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What are clinical features of acute osteomyelitis? What are features that may help differentiate this from other conditions?

A

Clinical features: acute onset, new limp, pseudoparalysis; possible fever in the days prior to presentation

Differentiating features: localized pain on palpation or point tenderness with pressure* particularly at distal or proximal ends of the bone; mild localized swelling or erythema

  • localized fluctuance may be present if there is a periosteal abscess
  • Fever may not be predominant feature at the time of presentation
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What are clinical features of transient synovitis of the hip? What are features that may help differentiate this from other conditions?

A

Clinical Features: age 4 to 10 years; hip pain and new limp; low grade fever; +/- weight bearing; history of URTI within 2 weeks prior

Differentiating Features: Non toxic with fever <38.5; CRP <20; gradually improves over days with NSAIDs

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

What are clinical features of fracture or trauma? What are features that may help differentiate this from other conditions?

A

Clinical features: acute localized pain while active; recognizable traumatic event

Differentiating features:
- Localized pain on palpation; hematoma or bruising to localized area; NO fever

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What are clinical features of Lyme arthritis? What are features that may help differentiate this from other conditions?

A

Clinical features: travel to Lyme endemic area within 2-12 months prior to onset*; monoarthritis with localized swelling; no history of constitutional symptoms

Differentiating features: still willing to weight bear; less painful than septic arthritis; no recent history of fever
CRP <40

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

What are clinical features cellulitis ? What are features that may help differentiate this from other conditions?

A

Clinical features: rapid development of redness, swelling, and pain over hours/day; erythema usually proceeds development of pain

Differentiating features: erythema, warmth, swelling, and tenderness of the skin; more extensive than one focal area; skin tender to touch; lymphangitis can be present
- May be able to bear weight and move joint

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

What are clinical features of chronic recurrent multifocal osteomyelitis (CRMO)? What are features that may help differentiate this from other conditions?

A

Clinical Features: insidious onset of bone pain; lesions effecting the metaphysis and epiphysis; may have low grade fever and malaise; pain often worse at night; lesions involve unusual sites such as clavicle, jaw and scapula; may seen intense sclerosis on radiograph

Differentiating features: localized tenderness; some warmth or swelling; 1/3 have low grade fever, malaise and weight loss; may have palmoplantar pustulosis, psoriasis, or other dermatologic conditions

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

What are clinical features of hematologic malignancy? What are features that may help differentiate this from other conditions?

A

Clinical Features: fever, fatigue, anorexia, weight loss, arthralgia, limb or muscle pain; Child may be
reluctant to walk or have metaphyseal lucencies and periosteal reactions

Differentiating Features: no localized pain to palpation but may have joint swelling and mild synovitis on joint examination
- May have fever

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

What are clinical features of bone neoplastic lesion? What are features that may help differentiate this from other conditions?

A

Clinical Features: typically occurs in the diaphysis or in flat bones. Typically gradual onset (over weeks). Pain is often worse at night and associated with refusal to weight-bear.

Differentiating Features: in addition to bone pain, may have a palpable soft tissue mass or bony mass.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

What are clinical features of JIA? What are features that may help differentiate this from other conditions?

A

Clinical Features: Typically gradual onset (over weeks). May be oligoarthritic (< 4 joints) or polyarthritic. More likely to be symmetric, often with extra-articular symptoms

Differentiating Features: Often symptoms are less severe compared with bacterial SA. May have contracture if more subacute. May need synovial fluid analysis to exclude SA when presenting with monoarthritis. Usually, fewer white blood cells in joint fluid compared with SA.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

What are clinical features of SLE? What are features that may help differentiate this from other conditions?

A

Clinical Features: Often constitutional symptoms (fever, weight loss, fatigue, anorexia, diffuse lymphadenopathy) predominate. Cutaneous symptoms (e.g., rash, ulcers) at presentation are also common.

Differentiating Features: Arthritis is usually milder than with SA. Child may also have hematologic (leukopenia, anemia) abnormalities and abnormal urinalysis.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

What are clinical features of reactive arthritis? What are features that may help differentiate this from other conditions?

A

Clinical Features: Oligoarthritis of larger joints, usually 2 to 3 weeks after a preceeding infection of the gastrointestinal or urogenital tract. May also have ocular and urinary symptoms.

Differentiating Features: Arthritis is more subacute and less severe compared with bacterial SA.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

What are clinical features of post-streptococcal reactive arthritis? What are features that may help differentiate this from other conditions?

A

Clinical Features: Acute onset of symmetrical or asymmetrical arthritis. Usually polyarticular, nonmigratory and can be persistent or recurrent. Usually 3–14 days after preceding streptococcal infection.

Differentiating Features: ay have extra-articular manifestations, (e.g., vasculitis, glomerulonephritis). In acute rheumatic fever, the joints are tender and swollen with a characteristic migratory feature and exquisite response to non-steroidal anti- inflammatory drugs or salicylates.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

What is the gold standard test for the diagnosis of AO?

A

Pathologic assessment of bone specimen

28
Q

What changes may be seen on CBC with AO?

A

Often seen WBC elevation

29
Q

How is CRP useful in the evaluation of AO?

A

Helpful!

Acute phase reactant with half life of 8 hours; sensitivity of 95%

30
Q

Which is the preferred test with AO- ESR vs CRP?

A

CRP! More sensitive and decreases with appropriate therapy

31
Q

What are the classic bone lesions seen on xray with AO?

A

Lytic lesions with localized periosteal reactions
Only appears 7-21 days after onset of infection* therefore if done when symptoms are more recent then sensitivity is low

Still should be done to rule out malignancy and fractures

32
Q

When is ultrasound a useful imaging modality?

A

Can be helpful to localize joint effusion in SA

Can sometimes distinguish between reactive and infectious arthritis

33
Q

Why is MRI useful for AO?

A

Most sensitive and specific non-invasive test
Provides information about the soft tissue and the growth plate
Can also quantify fluid within the growth plate

34
Q

Is MRI always required?

A

No! Not if there is a solid clinical diagnosis

35
Q

What is the sensitivity of bone scans? When are they indicated?

A

Radionucleotide bone scan can be used if MRI unavailable
Sensitivity around 80% but can have false negatives (ie: early during infection, AO associated with bone infarction)
False positives- with tumours or fractures
NOT as specific as MRI

36
Q

What is the utility of CT in detection of AO?

A

Not as sensitive as MRI

Can be used if MRI or bone scan is not available

37
Q

What is the best method to diagnose septic arthritis?

A

Joint aspiration

U/S can confirm the presence of joint effusion; MRI can help determine if inflammatory changes are present

38
Q

Prior to vaccinations, what was the most common cause of AO and SA?

A

Hemophilus influenzae type b

39
Q

What is the most common pathogen for SA and AO now?

A

Staph aureus (outside of neonatal period)

40
Q

In what age is Kingella kingae more common?

A

Children less than 4

41
Q

How can Kingella be detected?

A

Do not grow well on plated cultures from swabs but better when fluid samples are inoculated into blood culture bottles
Can do further molecular testing to confirm the diagnosis

42
Q

What are less common pathogens for AO?

A

Strep species- S pneumoniae, S pyogens and S agalactiae

Enterobacter and fungi* can occur in immunosuppressed populations and neonates
Salmonella- for sickle cell patients

43
Q

Why is it important to take an adequate sample for blood cultures?

A

More likely to yield enough volume to detect bacteria

44
Q

How much blood should be taken?

A

Recommended that a total of:
2 mL to 4 mL be drawn in children weighing 1 kg to 2 kg,
6 mL in children 2 kg to ≤12 kg
10 mL to 20 mL in children 13 kg to 40 kg,
40 mL in children > 40 kg

45
Q

When should joint aspiration in SA ideally occur?

A

Prior to starting antibiotics

46
Q

When should surgery be considered for AO?

A

Suspected subperiosteal fluid or abscess at presentation

47
Q

What should be done if patient fails to improve after a few days?

A

Repeat imaging to identify bone or joint fluid collections or soft tissue abscesses and reconsider debridement surgery if either of these signs are identified.

48
Q

What the antibiotic of choice for children wit AO or SA (among children who are fully immunized)?

A

First generation cephalosporin

In the absence of culture, can assume that it is due to either MSSA or Kingella Kingae (both of which are susceptible)

49
Q

What is the dose and frequency of antibiotic for AO or SA?

A

Cefazolin 100-150 mg/kg/day divided q6h or q8h

50
Q

What antibiotic if K. Kingae resistant to?

A

Clindamycin
Vancomycin
Cloxacillin

51
Q

When should antimicrobial coverage be broadended? To what antimicrobial?

A

For children: under 4, unimmunized, or living in areas with cases of invasive H fluenzae are more common
- Should then cover these patients with Cefuroxime 150 mg/kg/day IV q8h

52
Q

When should MRSA be considered?

A

If there is a high prevalence within the community or the child is known to be a carrier
*should add vancomycin to antimicrobial regime

53
Q

How should antimicrobial coverage be changed when sensitivities are back?

A

Should be narrowed
*most children can be narrowed from Cefazolin to Cloxacillin when MSSA is confirmed
Cloxacillin 150-200 mg/kg/day IV divided q6h

54
Q

What the traditional treatment course of AO?

A

Six weeks of IV therapy

55
Q

What do the studies show with respect to failure of IV vs oral treatment for AO?

A

Comparable failure rates
- One study: 4% in oral; 5% in IV
- Other study: 5% in oral; 6% in IV
Also noted to have increased complications with IV catheter use

56
Q

What are contraindications to transitioning from oral to IV therapy?

A

Poor medication compliance or follow up
GI malabsorption
Slow clinical resolution of infection

57
Q

When would it be appropriate to transition to oral therapy?

A

Based on clinical improvement and decrease in CRP

should have a negative blood culture

58
Q

How long does it take an uncomplicated AO to resolve>

A

Usually with 3-7 days of IV therapy with decrease in CRP and afebrile

  • lower extremity- should be able to bear weight
  • upper extremity- should be able to use it
59
Q

What does of Cephalexin dose can be used for oral step down? What dose of Cloxacillin?

A

Cephalexin - varying opinions on the exact dose
- Cephalexin 120-150 mg/kg/day orally TID
- Some clinicians prefer lower dose due to short half life
- Cephalexin 100-120 mg/kg/day orally QID
(Max 6 g/day)

Cloxacillin can also be used but tastes bad*
100 mg/kg/day QID (max dose 1 g)

60
Q

When should AO with MRSA be stepped down to oral? To what agent?

A
  • Should consult ID
  • Usually longer IV course before switching to oral
  • Oral options include clindamycin, TMP-SMX, or linezolid
61
Q

What is the current recommended treatment course for uncomplicated AO? What about SA?

A
  • 3-4 weeks total therapy for both AO and SA
    • SA of the hip- still recommend 4-6 weeks
  • Recommendations apply regardless of whether blood cultures were positive and ALWAYS assume positive clinical response
62
Q

When should clinical follow up occur?

A

Always prior to the discontinuation of antibiotics with normal CRP being observed

63
Q

When are radiographs indicated at the end of treatment course?

A

Routine radiographs at the end of therapy are only clearly indicated when the growth plate is involved and/or a large lytic lesion presents initially

64
Q

When is orthopedic follow up indicated?

A

Where the infection involved the growth plate or an immediately adjacent epiphyseal or metaphyseal region

65
Q

When is MRI indicated at the end of treatment?

A

Reserved for patients who develop complications or who are not clinically improving

CPS Statement Flash Cards (10 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions