Bone and Joint Infections Flashcards

1
Q

Who should get pseudomonal coverage in a diabetic foot infection? [2]

A
  1. Exposure to water
  2. Clinical failure while receiving nonpseudomonal therapy

–> Pseudomonas is implicated only in a small percentage.

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2
Q

Labs to order in diabetic foot infection? [5]

A
  1. CBC
  2. CMP
  3. A1c
  4. ESR/CRP
  5. Blood cultures
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3
Q

Mgmt of foot ulcer in a patient with DM without redness, warm, swelling, drainage or order

A

Local wound care

No abx.

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4
Q

Length of abx therapy for diabetic foot infection?

A

4-6 weeks if no surgical debridement

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5
Q

Definition of a mild diabetic foot infection?

A

Do not extend deeper than skin and subcutaneous tissues, erythema is <2 cm from ulcer

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6
Q

Definition of a moderate diabetic foot infection?

A

Infection extends deeper than skin and subcutaneous tissues, erythema is >2 cm from ulcer

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7
Q

Definition of a sever diabetic foot infection?

A

There is associated systemic signs and symptoms.

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8
Q

Treatment of a mild diabetic foot infection? [3]

A
  1. Bactrim
  2. Clinda
  3. Doxy

–> MRSA/MSSA likely etiology

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9
Q

Treatment of a moderate diabetic foot infection? [2]

A
  1. Bactrim + Augmentin

2. Clinda + Fluoquinolone [Cipro, levo, moxi]

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10
Q

Three mechanisms of septic arthritis development? [3]

A
  1. Hematogenous spread from distant foci of infection [endovascuar, odontogenic]
  2. Contiguous spread [steroid injection, trauma]
  3. Extension from osteomyelitis
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11
Q

Most commonly involved joints in septic arthritis? [5]

A
  1. Knee [50%]
  2. Hip
  3. Shoulder
  4. Elbow
  5. Ankle
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12
Q

What joint involvement should prompt evaluation for IVUD? [2]

A
  1. SI joint

2. Sternoclavicular joint

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13
Q

Labs to obtain in evaluation of septic arthritis [4]

A
  1. CBC
  2. CMP
  3. ESR/CRP
  4. Blood cultures [positive in up to 50% of cases]
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14
Q

What joint fluid studies be sent

A
  1. Cell count and diff
  2. Gram stain and cultures [Aerobic, anaerobic, fungal AFB]
  3. Crystal analysis
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15
Q

Imaging studies to get?

A
  1. X-ray
  2. MRI [or CT if you cant get an MRI]
  3. Echo if endocarditis is suspected
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16
Q

How does disseminated gonococcal infection present?

A

Arthralgias [migratory], tenosynovitis [extensor] and rash [arthritis-dermatitis syndrome].

Purulent distal mono or oloigoarthritis can be seen in 1/3 of uncreated cases effecting the knees, wrists, and ankles.

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17
Q

Describe the cutaneous findings in a DGI

A

Maculopapular rash to pustular dermatosis of the palms and soles with 10-15 lesions on average.

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18
Q

Organisms to cause septic arthritis postpartum or in a recent history of GU tract manipularion

A

Mycoplasma hominis

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19
Q

Who gets GBS septic arthritis

A

Poorly controlled DM, cancer

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20
Q

Who gets strep pneumo septic arthritis

A

Those with splenic dysfunction

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21
Q

Describe the WBC count, PMN%, and appearance of the synovial fluid in non-inflammatory OA.

A

WBC: <200
PMN%: <25
Fluid: Transparent

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22
Q

Describe the WBC count, PMN%, and appearance of the synovial fluid in a normal patient

A

WBC: <200
PMN%: <25
Fluid: Transparent

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23
Q

Describe the WBC count, PMN%, and appearance of the synovial fluid in inflammatory arthritis [gout, pseudogout, RA]

A

WBC: >2,000
PMN: 50% or more
Fluid: Mildly opaque

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24
Q

Describe the WBC count, PMN%, and appearance of the synovial fluid in septic arthritis

A

WBC: >50,000
PMN: 75% or more
Fluid: Cloudy

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25
Q

Describe the WBC count, PMN%, and appearance of the synovial fluid in hemarthrosis

A

WBC: Variable, may be falsely elevated due to RBCs
PMN: 50-75%
Fluid: Bloody

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26
Q

Diagnosis of DGI?

A

NAAT of throat, rectum, urethra

NAAT of synovial fluid

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27
Q

Treatment of DGI?

A
  1. Ceftriaxone 1g IV q24 + Azithro 1g PO 1x.

2. May step down to doxycycline or cefixime if susceptible.

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28
Q

How does lyme arthritis present?

A

Monoarthritis in the knee most commonly

May not have systemic symptoms

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29
Q

Diagnosis of lyme arthritis

A

PCR for lyme in the synovial fluid

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30
Q

Treatment of lyme arthritis?

A
  1. Doxy
  2. Amoxicillin [alt]
  3. Cefuroxime [alt]

30 days of treatment

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31
Q

Most common nontuberculous mycobacteria that cause septic joints? [2]

A
  1. Chelonae

2. Fortuitum

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32
Q

Most common cause of fungal septic arthritis

A

Candida

–> Uncommon

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33
Q

Lab work up of septic arthritis? [5]

A
  1. CBC
  2. CMP
  3. CPK
  4. ESR/CRP
  5. Viral serologies?
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34
Q

Viruses that may cause inflammatory arthritis?

A
  1. HIV
  2. HBV
  3. HCV
  4. Parvo B19
  5. Alphaviruses [Chikungunya]
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35
Q

Presentation of HBV arthritis

A
  1. RA like in the prodromal stage of hep B which resolves with development of jaundice
  2. Less RA like in setting of chronic infection
36
Q

Presentation of HCV arthritis

A
  1. RA-like pattern

2. Oligoarthritis with involvement of larger joints which can be associated with mixed essential cryolobulinemia

37
Q

Joint manifestations of chikungunya

A

Affects both small and large joints
Typically >10 joints affected
Associated rash and high fever
1/3 develop chronic symptoms with relapsing-remitting or unremitting patterns

38
Q

Diagnosis of chikungunya

A

PCR if symptoms <1 week

IgM/IgG if >1 week

39
Q

What HLA is reactive arthritis a/w?

A

HLA-B27

40
Q

Presentation of reactive arthritis?

A
Asymmetric oligoarthritis of large joints
Urethritis
Uveitis or Conjunctivitis
Enthesitis
Dactylitis
Keratoderma blennorhagica
41
Q

Organisms a/w reactive arthritis? [5]

A
  1. Chlamydia
  2. Shigella
  3. Salmonella
  4. Campy
  5. Yersinia
42
Q

Diagnosis of reactive arthritis?

A

Exclusion

43
Q

Mgmt of bacterial non-gonoccal septic arthritis

A

4 weeks of directed therapy

44
Q

Mgmt of fungal and tuberculous septic arthritis

A

At least 6 months abx + surgery

45
Q

Uncommon way vertebral osteo can be caused?

A

Esophageal perforation

GI tract in inflammatory bowel disease

46
Q

Most common area in the back vertebral osteo occurs? [3]

A
  1. Lumbar
  2. Thoracic
  3. Cervical
47
Q

Labs to obtain in vertebral osteo? [4]

A
  1. CBC
  2. CMP
  3. ESR/CRP
  4. Blood cultures [+ >75% of cases]
48
Q

When should you give abx prior to biopsy in vertebral osteo? [2]

A
  1. Unstable
  2. Neurologic compromise

–> Otherwise should be held until a microbiologic diagnosis is made.

49
Q

Etiology of vertebral osteo

A
  1. Staph aureus >50%

2. Enteric GNR ~30% [predominately lumbar spine]

50
Q

Who gets GBS vertebral osteo

A

Poorly controlled DM

51
Q

Who gets coag-negative stapg vertebral osteo?

A

Those with hardware

52
Q

Who gets pseudomonas vertebral osteo?

A

Immunocompromise, IVDU

53
Q

Who gets salmonella vertebral osteo

A

Sickle cell disease patients

54
Q

Who gets candida vertebral osteo?

A

IVDU, those with indwelling caths

55
Q

What part of the spine does TB present in?

A

Thoraco-Lumbar

56
Q

How does TB vertebral osteo look on imaging?

A

Spreads along the anterior ligaments of the vertebra, spares disc space until late in disease.

57
Q

What infection presents as sacroiliitis or spondylodiscitis a/w consumption of unpasteurized milk and cheeses in the Middle East and Mediterranean?

A

Brucellosis

58
Q

Tx of vertebral osteo? [3]

A

6-8 weeks of targeted abx for bacterial
12 weeks for brucella
24 weeks for fungal or AFB [standard RIPE therapy]

59
Q

Define an early PJI. Etiology?

A

Onset <3 months from surgery. Acquired during joint implantation.
Staph aureus

60
Q

Define a delayed PJI. Etiology?

A

Onset3-24 months from surgery. Acquired during joint implantation.
Coag negative staph, Cutibacterium

61
Q

Define a late PJI. Etiology?

A

Onset >24 months from surgery due to hematogenous spread

Staph and Strep

62
Q

PJI mimics?

A
  1. Metallosis [metal on metal wear of endoprosthesis leading to a local hypersensitivity reaction].
  2. Aseptic loosening
  3. Crystalline arthropathy
63
Q

Organisms that can lead to PJI of the shoulder but rarely in the hips or knees?

A

Cutibacterium acnes

64
Q

Cause of culture negative PJI?

A
  1. Pre-treatment with abx
  2. Brucella
  3. Coxiella
65
Q

Labs to order in PJI?

A
  1. CBC
  2. CMP
  3. ESR/CRP
  4. Blood cultures
66
Q

Dx of PJI?

A

Arthrocentesis [hold abx until after if pt is stable]

67
Q

What studies should be ordered from arthrocentesis?

A
  1. Gram stain and culture [aerobic, anaerobic, fungal, TB]
  2. Cell count and diff
  3. Crystal analysis
  4. ?Alpha-defensin
68
Q

Treatment of an early PJI?

A

DAIR [Debridement, Antibiotics, Implant Retention]

  • Only if it is well fixed prosthesis
  • Must NOT have sinus tract
  • 2-6 weeks IV abx followed by 3-6 months of PO abx with rifampin if Staph is involved
69
Q

Treatment of late PJI

A

Two stage exchange
Stage 1 is prothesis excision with placement of antibiotic laden cement as a temporary spacer for 6 weeks
Check for treatment response with ESR/CRP
Stage 2 is reimplantation
6 weeks of IV abx for this.

70
Q

NOTE

A

For PJI add rifampin if there is Staph causing the infection.

71
Q

What is Brodie’s Abscess

A

Subacute hematogenous osteomyelitis

72
Q

Who gets Brodie’s Abscess

A

Children and young adults

73
Q

MRI finding with Brodie’s Abscess?

A

Penumbra sign on MRI

74
Q

Pathophysiology of Brodie’s Abscess

A

Bacterial deposit in the medullary canal of a metaphyseal bone [this area is super vascular]

75
Q

Most common cause of Brodie’s Abscess

A

Staph aureus

76
Q

For vertebral osteo when is a tissue sample NOT needed?

A

When blood cultures grow staph aureus or lugdunensis

77
Q

If in vertebral osteo the tissue sample is negative what is the next step?

A
  1. Repeat biopsy

2. Open surgical biopsy

78
Q

Presentation of Potts disease

A

Indolent

Often constitutional symptoms but may not have.

79
Q

What is a gibbus deformity?

A

This is anterior collapse of the vertebral body in Potts disease

80
Q

Causes of culture negative Septic Arthritis?

A
  1. HACEK
  2. Gonococcal
  3. Mycoplasma
  4. Lyme
81
Q

What might make the diagnosis of delayed PJI challenging?

A

WBC count >3000 considered PJI until proven otherwise
ESR/CRP may not be elevated
Cultures only 50-60% positive
Symptoms are indolent

82
Q

Treatment of staph aureus infection of PJI in which hardware is maintained?

A
  1. 4-6 weeks of IV abx targeted with rifampin

2. Oral abx + rifampin for additional 2 months. [often quinolones in combination with rifampin]

83
Q

Who gets 1 stage exchanges? How long are they treated?

A

Acute infections, subacute infections with healthy tissues of the HIP ONLY.
2-6 weeks of IV abx with 3-6 months of PO abx with rifampin if staph.

84
Q

Who gets 1 stage exchanges? How long are they treated?

A

Acute infections, subacute infections with healthy tissues of the HIP ONLY.
2-6 weeks of IV abx with 3-6 months of PO abx with rifampin if staph.

85
Q

What type of morphology does mycoplasma have on culture plate?

A

“Fried Egg”

86
Q

What is Madura Foot?

A

Chronic SSTI due to mold in those that walk barefoot. May cause osteomyelitis