Osteomyelitis

Question 1

What must occur to create osteomyelitis

Answer 1

Negative event like trauma or foreign body or inoculation with biofilm producing or implant adhering infectious agent

Question 2

How is osteomyelitis classified in vet med

Answer 2

Route of infection (hematogenous or post traumatic)

Time of disease onset (acute, subacute, chronic)

Question 3

osteomyelitis time line

1) Acute
2) Subacute
3) Chronic

Answer 3

1) develops within two week
2) develops within several months
3) develops after a few months

Question 4

What is a major predisposing factor in the development of osteomyelitis and how does it occur

Answer 4

Ischemia. Loss of vascular channels (Haversian and Volkmanns canals and canniliculi) secondary to necrosis and resorption during acute inflammatory phase

Question 5

Radiographic evidence suggestive of the aggressiveness of the infection

Answer 5

Less aggressive appears as thickening of the bone
More aggressive shows a lamellated (onion skin) layering
Aggressive calcified streaks perpendicular to the bone

Question 6

What influences the damage from and response to treatment of osteomyelitis

Answer 6

Viability of the bone
Virulence of the infectious orgs
Condition of the soft tissue envelope

Question 7

Where does hematogenous osteomyelitis usually occur

3 reasons why

Answer 7

Metaphysis
sinusoidal capillaries (no basement membrane (BM), discontinuous endothelium/capillary)
Sluggish circulation
No leukocytes in developing spongiosa

Question 8

Most common cause of osteomyelitis and organism

Answer 8

Trauma and Staphylococcal 60% (particularly Staph intermedius

Question 9

4 stages of a biofilm

Answer 9

Reversible attachement, irreversible attachment, growth and differentiation, dissemination or detachment

Question 10

Why are biofilms resistant to antimicrobials

Answer 10

Acts as a filter and barrier
Quiescent growth (If MOA impedes growth and repro its ineffective)
Harsh environment (acidic, increased PCO2 and low PO2)

Question 11

Diagnosis

Answer 11

Biopsy and culture

Question 12

Tx

Answer 12

Drain, debridement (explant), lavage
IV abs (5-7 days) then oral for at least 4 weeks

Question 13

Azab, MA et al. VCOT 2016

Eval of silver impregnated coating for implants to inhibit colonization of meth resist staph pseudointermedius

Answer 13

Reduced MSRP colonization by 99.98% after 24 hours of inoculation