Osteomyelitis and osteosarcoma Flashcards Preview

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Flashcards in Osteomyelitis and osteosarcoma Deck (13):
1

What disease types can relate to bone?

- autoimmunne (unusual in bone)
- developmental
- degenerative (mostlyjoints)
- endocrine
- infectious
- inflammatory - joints (rare for bone itself)
- metabolic
- neoplastic
- traumatic (fractures)
- vascular (specific problems uncommon)

2

Define osteomyelitis

infection of cortical bone AND medullary cavity (many people call it this even if one structure is affected)

3

Define osteitis

inflammation of cortex without involvement of the red or yellow bone
- septic or aseptic

4

Classic acute presentation

- large/small animl
- single limb lameness
- rapid onset, short duration
- often hx of a laceration or sx
- CE: heat, pain, swelling on palpation, joint structures may be normal, febrile
* ensure you distinguish joint from bone

5

Classic chronic presentation

- large/small
- moderate? intermittemt? lameness of days-wks
- often hx of laceration or sx
- CE: possible heat, pain, swelling on palpation, joint structures may be normal, pain, discharge, sinus tract formation, pathological fracture (becomes acute)

6

What are the 2 main reactions to bone disease?

- bone lysis (driven by infection)
- bone formation (Reactive)
- combination of both, seen with infxn and bone tumour
- radiographic signature of osteomyelitis

7

Diagnostic plans for bone disease

- radiography
- culture and sensitivity
- biopsy
- radionuclide scan (v good at determining high levels of bone activity, useful if radiography doesn't show draining tracts)
- similar radiographic appearance b/w osteomyelitis and OSA so take care when making radiographic dx

8

Tx - osteomyelitis

- early intervention with BS Abs
- change on C+S
- consider local delivery (gentamicin)
- sx debridement, immbolisation, lavage
- rehabilitation of entire limb

9

Most common primary bone tumour - dogs

OSA (very rare in horses and cats)

10

How to investigate a possible bone tumour

- clinical evaluation: LNs, degree of disability
- Radiography - local and thoracic
- Swab tracts, culture and sensitivity on samples
- Biopsy: Jamshidi, # of planes
- definitive diagnosis - biopsy or culture
- Staging/evaluation of prognosis

11

Describe bone biopsy

- Jamshidi needle or Michelle trephine
- trough the centre of lesion (not margins)
- sample both cortex and medulla
- multiple samples (through same skin incision)
- cytology and culture

12

Decision making in OSA tx

- unremittingly painful (analgesia won't do)
- must tx primary successfully
- must consider primary spread (nearly all OSAs have micro mets in lungs at time of dx)
- must build client communication into tx time (high emotional impact, very serious very quickly - lameness to life ending disease dx may occur in 3 wks)

13

OSA tx

- amputation (4 months)
- amputation (remove whole LN chain with it) + chemo (12-14mo)
- limb sparing and chemotherapy (12-24 mo)
- radiotherapy (palliative only)
- NSAIDs/ bisphosphonates (palliative)
- euthanasia