Bone and Joint infections - Glew

Question 1

In hematogenous seeding of infection into bone, where does the infection go in:

Children?

Adults?

Answer 1

Children - long bones at the metaphyses

Adults - vertebral osteodiscitise

Question 2

Contiguos inoculation/spread is via?

Answer 2

trauma

surgery

vascular insufficiency –> ulcer

Question 3

What are the most common pathogens in the hematogenous spread of infections to the vertebral column (verterbal osteodiscitis)?

Answer 3

S. aureus (skin)

Viridians group Streptococcus (teeth/GI)

GNBs (UTI via Batson plexus)

Pathophysiology - adjeacent vertebrae and intervening discitis

Complications - epideural abscess

Question 4

What are the clinical symptoms of vertebral osteodiscitis?

How do you diagnose it?

Answer 4

Back pain

Redness /swelling

Fever is variable; rare in elderly

Spine tendernes

Dx:

↑C-reactive protein (CRP)
Blood cultures - Increased WBC
Imaging - MRI > CT
IR - needle aspirate/biopsy → cultures

Question 5

Contiguous spread sources in osteomyelitis and pyarthrosis?

Answer 5

1. Open fracture
2. Penetrating trauma
3. Orthopedic surgery

• Complication of
  
  • Open Reduction/Internal Fixation
  • Total Joint Prostheses

4. Diabetes mellitus → ulcer
5. Decubitus ulcer

Question 6

Contiguous/traumatic pyarthrosis and osteomyelitis diagnostic features

Clinical

Lab

Imaging

Cultures

Answer 6

1.Clinical
Source - trauma, surgery, wound
Pain
Redness/swelling

2. Lab
   ↑CRP
   ↑WBC

3.Imaging - MRI > CT

4.Cultures
Blood
Bone (surgical biopsy)/Joint fluid (aspirate)

Question 7

What are the pathogens involved in contiguos/traumatic osteomyelitis/pyarthrosis?

Answer 7

Mixed flora:

Staph. aureus
Coagulase-negative Staph.
Streptococcus species
GNBs
Anaerobes

Question 8

Which pathogens do you get from these methods of infection and their specific treatments

Clenched fist injury/human bite

Animal bites

Foot - puncture wound

Answer 8

Clenched fist injury/Human bite
Staph., Strep, anaerobes, Eikenella

Tx: vancomycin plus Carbapenem

Animal bites
Cat - P. multocida
Dog - Pasteurella spp., S. aureus, anaerobes

Tx: Ceftriaxone (plus vancomycin if dog bite)

Foot - puncture wound
Pseudomonas aeruginosa

Tx: Ciprofloxacin if bone divot

Vancomycin if no bone injury

Surgery can also be done with debridement and soft tissue coverage

Question 9

What antibiotics do you use for:

Staph aureus

Coagulase negative staphylococcus

Streptococcus species

Gram-negative Bacilli

Answer 9

• Staphylococcus aureus
  
  • MSSA - Cefazolin (or Nafcillin) IV
  • MRSA - Vancomycin IV (or Linezolid or Daptomycin)
• Coagulase-negative Staphylococcus
  
  • Vancomycin IV (or Linezolid)
• Streptococcus species
  
  • Ceftriaxone IV (or Ampicillin)
• Gram-negative Bacilli (per susceptibilities)
  
  • Fluoroquinolone IV/PO (or 3rd Cephalosporin)

Question 10

What are the two big infectious agents in total joint arthroplasties?

Answer 10

Coag-neg Staph

Staph aureus

Question 11

What are the three options in management of total joint arthroplasty?

Answer 11

Two stage removal

Debridment and retention

Resection arthroplasty

Question 12

What are the total joint arthroplasty infectious agents and what antibiotics would you treat them with?

Answer 12

Coagulase-negative Staphylococcus
Vancomycin* (or Linezolid)

Staph. aureus
MSSA - Cefazolin* (or Nafcillin)
MRSA - Vancomycin*
(or Linezolid or Daptomycin)

Streptococcus species
Ceftriaxone (or Ampicillin)

Gram-negative Bacilli
Fluoroquinolone (or 3rd gen Cephalosporin)

Question 13

There are three categories of hematogenous pyarthosis. What are they and what are the infectious agents?

Answer 13

General - S. aureus

Elderly (vertebral) - S. aureus > GNB

Sexually-transmitted disease-related - Neisseria gonorrhea

Question 14

What is the pathophysiology of pyarthosis

Answer 14

The synovium has no basement membrane and is highly vascula - therefore it is easily seeded

PMNs are also present - they release osteolytic enzymes that destroy cartilage and bone

Question 15

What are the etiologies of pyarthrosis?

Answer 15

Pyarthrosis can be bacterial or microcrystalline

BACTERIAL

• Gonococcal
  
  • As part of disseminated Gonococcal infection
• Non-Gonococcal
  
  • S. aureus/Streptococcus species
• Lyme Borreliosis
  
  • Uncommon
  • Chronic
  • Monoarticular - knee
  • With or without antecedent systemic Lyme Disease

MICROCRYSTALLINE
Gout (urate)
Pseudogout (Ca++ pyrophosphate)

Question 16

What are the non-infectious etiologies of pyarthrosis?

Answer 16

REACTIVE POST-INFECTIOUS ARTHRITIS (REITER’S SYNDROME)

Enterititis:

• Shigella/Salmonella
• Campylobacter/Yersinia

Urethritis:

• Chlamydia trachomatis

CONNECTIVE TISSUE DISORDERS
Rheumatoid Arthritis
Juvenile Rheumatoid Arthritis

Question 17

What is Reiter’s syndrome?

Answer 17

This is a reactive post infectious arthritis

Question 18

Where can a patient get pyarthrosis from and what infectious agent would it be?

Answer 18

BACTEREMIA (normal host/normal joints)

• Staph. aureus
• Streptococcus species

INJECTION DRUG USE (including fibrocartilaginous joints)

• Staph. aureus
• GNB

SEXUALLY-TRANSMITTED DISEASES

• N. gonorrhoeae
• Chlamydia → Reiter’s Syndrome

Question 19

What is the clinical presentation of pyarthrosis?

Answer 19

1. Fever & chills
2. Malaise
3. Affected joint

• Large, weight-bearing
• Hot
• Swollen/effusion
• ↓Mobility

Question 20

What is important in the diagnosis of pyarthrosis

Answer 20

Look at the joint aspirate for - PMNs. gram stain/culture, rule out crystals

Blood cultures - although they are positive in less than 50% of cases

Question 21

How do you treat pyarthrosis?

Answer 21

Antibiotics

Aspiration

Arthroscopy - debridement, irrigation