Mhd - #12 - Bone And Joint Infections

Front 1

Osteomyelitis vs Septic arthritis?

Back 1

osteomyelitis: an abscess in bone; requires bone resection and antimicrobial therapy to stop infection

septic arthritis: a closed space infection in synovial lined joint as opposed to inflamm in joint space

**both can present w/ similar clinical features

Front 2

Bone architecture?

Back 2

bones are composed of cortex* of compacted or lamellar* bone and a medulla* of spongy or cancellous* bone

Front 3

4 groups of bones?

Back 3

1. tubular
2. cuboidal
3. flat
4. irregular

Front 4

Heamtogenous spread of osteomyelitis promoted by skeletal tissue w/:

Back 4

1. rich arterial supply
2. sluggish sinusoidal flow
3. marrow cavity

Front 5

Pathophysiology of hematogenous osteomyelitis?

Back 5

bacteremia --> deposition w/in sinusoidal veins initiates inflamm response which cuts off blood suplly --> necrosis, abscess formation and sequestration of infarcted bone

Front 6

Risk factors for hematogenous osteomyelitis (4):

Back 6

1. hemoglobinopathies lead to reduction of RES to phagocytize circulating bacteria

2. chronic granulomatous disease of childhood

3. pre-existing infection of GU orrespiratory tract or skin

4. IV access

Front 7

Another way hematogenous infection may spread:

Back 7

infected material goes thru cortical canals into subperiosteal space --> joint space or to cutaneous surface as sinus tract

Front 8

Risk factors for hematogenous osteomyelitis (4):

Back 8

1. hemogloboninopathies - leads to reduction of RES to phagocytize circulating bacteria
2. chronic granulomatous disease of childhood
3. pre-existing infection of GU or resp tract or skin
4. intravenous access

Front 9

What is Contigous Focus Osteomyelitis?

Back 9

=skeletal tissue adjacent to infected soft tissue becomes infected (iatrogenic/otherwise)

Front 10

Pathophysiology of contiguous focus osteomyelitis (4):

Back 10

1. adjacent soft tissue
2. devitalized bone
3. presence of foreign bodies
4. bone instability

Front 11

What is Vascular Insufficiency-Associated Osteomyelitis?

Back 11

=contiguous infection in the small bones of the feet seen in patients w/ severe peripheral vascular disease

Front 12

Pathogenesis of vascular insufficiency-assoc osteomyelitis (4):

Back 12

1. DM or generalized severe atherosclerotic disease
2. neuropathy
3. vasculopathy
4. tissue necrosis w/ subsequent infection

Front 13

What is the single most common pathogen in osteomyelitis?**

Back 13

Staphylococcus aureus**

Front 14

Virulence factors associated with osteomyelitis:

Back 14

Staph aureus:
-intracellular pathogen survival
-adherence factors
-inflamm response mediators

Front 15

Table 1: Microorganisms Isolated from Patients w/ Bacterial Osteomyelitis

Back 15

see Table 9 (???)

Front 16

Types of infectious arthritis?**

Back 16

1. Pyogenic (septic arthritis)
2. Reactive "Post-Infectious/Inflamm" Arthritis

Front 17

Risk factors for infectious arthritis?

Back 17

-host phagocytic defects
-impaired host defense mechanisms
-direct penetration
-joint damage

Front 18

Characteristics of pyogenic (septic) arthritis?

Back 18

-monoarticular
-usually hematogenous in origin
-acute synovial inflamm leads to cartilage destruction if untreated

Front 19

What microbial pathogens are most commonly found in native joints of:

1. elderly?
2. pre-adolescents?
3. adolescents?

Back 19

elderly and pre-adolescents: Staph aureus, Strep, GNR

adolescents/young adults: Gonococcus (sexually active)

Front 20

What microbial pathogens are most commonly found in PROSTHETIC joints of:

early onset?

late onset?

Back 20

early onset: S. aureus, CNS, GNR

late onset: Strep, CNS, GNR

Front 21

What is "post-infectious/inflammatory" arthritis?

Back 21

=deposition of bacterial antigens, Ig, complement components, circulating immune complexes, and exotoxins --> inflamm response in synovial space

Front 22

Reactive "Post-infectious/Inflamm" Arthritis:

aka?
causes?
findings?
systemic diseases associated?

Back 22

aka: crystal deposition disease

findings: hemarthrosis

causes: foreign body rxns/trauma

systemic diseases: LRA, SLE, IBD, psoriasis, Bechet's, Reiter's syndrome

Front 23

Therapeutic approach to bone and joint infections:

Back 23

1. surgical intervention
2. antimicrobial therapy

Front 24

Long-term management of bone infection:

Back 24

1. follow-up
2. chronic suppressive therapy
3. management of relapse episodes