Lecture 10 - Bone & Joint

Question 1

Osteomyelitis

Answer 1

inflammation of bone caused by an organism

infection can remain localized or spread through bone

Question 2

“Long bone”

Answer 2

Have 2 defined ends and a shaft
Longer than it is wide
Almost all done of Arms & Legs are considered “Long bones”

Question 3

Cortical bone

Answer 3

thicker outer surface of long bones

Question 4

Cancellous bone

Answer 4

found at ends of long bones

Question 5

Acute Osteomyelitis

Answer 5

presents within 1/2 wks of bone infection
untreated can progress to chronic

Question 6

Chronic Osteomyelitis

Answer 6

Typically 6+ wks after bone infection, bone destruction is common

Question 7

Hematogenous Osteomyelitis is usually

Answer 7

usually monomicrobial

Question 8

Contiguous Osteomyelitis is usually

Answer 8

usually polymicrobial

Question 9

Common causes of Osteomyelitis?

Answer 9

> 50% = Staph aureus + coag neg staph

Question 10

Hematogenous Osteomyelitis info

Answer 10

can effect any bone, commonly tibia or femur

Question 11

Hematogenous Osteomyelitis risk factors

Answer 11

endocarditis
IV access devices
HD

Question 12

Nonhematogenous (contiguous) Osteomyelitis info

Answer 12

direct entrance from trauma = pen wound, open fracture, surgery, pressure ulcer

progressive spread from adjacent tissue, often involves fingers and toes

Question 13

Stage 1: Medullary Osteomyelitis

Answer 13

usually treated ABX alone in kids, ABX/debridement in adults

confide to intramedullary surfaces of bone

Question 14

Stage 2: Superficial osteomyelitis

Answer 14

cortical bone infection where necrotic surface of bone lies at base of soft tissue wound

Question 15

Stage 3: Localized osteomyelitis

Answer 15

clearly defined bone infection that can be removed surgically without compromising bone stability

Question 16

Stage 4: Diffuse osteomyelitis

Answer 16

Infection spread through entire bone w/ instability

Question 17

Clinical Presentation Osteomyelitis

Answer 17

tenderness/pain around infected area
Absence of systemic signs/symptoms is common

acute infection occurs within 1/2 wks after inoculation of bone

Hallmark = deadline tissue + involucrum

Question 18

Diagnosis Osteomyelitis

Answer 18

radiographs or bone scas, changes noted 10-14 days after onset

CT or MRI = standard of care

Question 19

Stage 1/2 txm duration

Answer 19

1-2 weeks

Question 20

Stage 3/4 txm duration

Answer 20

4-6 weeks

Question 21

Pharmacologic principles for consideration

Answer 21

Pen of ABX into bone is poor
Pen differ based on cortical (dense) vs Cancellous (spongy) bones

Question 22

Empiric Osteomyelitis < 6 months

Answer 22

1st/2nd gen cephalosporin or anti-stap penicillin + gent (if < 3 months)

Question 23

Empiric Osteomyelitis 6-48 months

Answer 23

1st/2nd gen Cephalosporin
Clindamycin if local MRSA > 10%

Question 24

Empiric Osteomyelitis > 5 yrs

Answer 24

1st2nd gen cephalosporin or anti-staph penicillin
Clindamycin if local MRSA > 10%

Question 25

Vertebral Osteomyelitis w/ High risk factors

Answer 25

Atleast 6 weeks of antimicrobial therapy (IV+oral)

Question 26

Vertebral Osteomyelitis w/o High risk factors

Answer 26

4-6 weeks of antimicrobial therapy (IV+oral)

Question 27

Acute osteomyelitis in childhood, mostly long bones

Answer 27

2-3 wks of antimicrobial therapy (IV+oral)

Question 28

Chronic osteomyelitis, diabetic foot Osteomyelitis w/ adequate surgical debridement

Answer 28

4-6 wks of antimicrobial therapy (IV+oral)

Question 29

Rifampin info

Answer 29

often added on when concern for biofilms exist (implantable hardware), never used alone

Question 30

Polymethylmetharcrylate (PMMA) Beads

Answer 30

bone cement impregnated w/ ABX, typically gent

can be used to replace lost bone

Question 31

Hyperbaric oxygen therapy

Answer 31

100% oxygen delivered under pressures artificially elevated above atmospheric pressure at sea lvl

pens bone/tissue an causes bacterial lysis and inc collagen/fibroblasts

Question 32

infectious arthritis

Answer 32

infection of cartilage and synovial fluid

can rapidly progress to an emergency due to potential for rapid joint destruction

Question 33

Risk factors for septic arthritis of native joints

Answer 33

Preexisting joint diseases
DM
IV drug use
Cirrhosis
ESRD
Prednisone + other immunosuppressive meds
Skin disease = psoriasis, eczema, skin ulcers
Human bites

Question 34

Infectious Arthritis presentation

Answer 34

seen mostly in knees but also wrist,, fingers, ankles and hips

blood cultures apron 50% of time, remove fluid and send to culture

Question 35

Gram positive txm for infectious arthritis

Answer 35

Vanco ( + or > 10% MRSA) or Cefaozlin ( < 10% MRSA)

Question 36

Gram neg cocci or suggestive of disseminated gonococcal infection txm for infectious arthritis

Answer 36

ceftriaxone 1g q24h + azithromycin 1 dose

Question 37

Gram neg rods txm for infectious arthritis

Answer 37

cefepime 2g q8hr or pip/tazo 4.5g q6h

Question 38

if no organisms sen on gram stain Txm for infectious arthritis

Answer 38

vancomycin 1g q12hr (Cefazolin if low MRSA presence)

add cefepime or pip/tazo in elderly, immunocompromised, critically ill, IV drug users

Question 39

Adult Tx for infectious arthritis

Answer 39

3-4 weeks, atleast 2 weeks IV

Question 40

pediatric Tx for infectious arthritis

Answer 40

uncomplicated, 10 days min, if complicated( bones involved) then 3-4 weeks

Question 41

Gonococcal infection txm

Answer 41

2 weeks ceftriaxone + 1 dose azithromycin

Question 42

Cartilaginous joints (sternoclavicular or sacroiliac) txm

Answer 42

6 weeks due to osteomyelitis