Osteomyelitis and Ostosarcoama (Pead)

Question 1

What type of iseae is osteomyelitis?

Answer 1

Infectious

Question 2

Which types of diseae are common in bone and joints?

Answer 2

> Developmental
> Endocrine/metabolic
> Infectious (myelitis) 
> Neoplastic (Osteosarc) 
> Trauma (fx)
- vascular (rare)
- autoimmune (rare)
- degenerative (more joints)
- inflammatory (more joints)

Question 3

Strict defintition of osteomyelitis? Used for?

Answer 3

> infection of corticol bone and medullary cavity

- used for any infection of bone

Question 4

What i osteitis?

Answer 4

• term used by pahologists

- describes infection of cortex without involveent of red or yellow BM

Question 5

What forms of osteomyelitis?

Answer 5

> Acute
- large or small animals
- sngle limb lamness, rapid onset, short duration
- often Hx of laceration or surgery
- clinical exam (heat, pain, swelling on palp, joint structures may be normal,febrile)
- differentiate joint from bone
Chronic
- largies/smallies
- moderate intermitent lamenss days/weeks
- hx laceration or sugery
- clinical exam (MAY BE heat, pain, swelling, pain, discharge, sinus tract, pathological fx then becoems acute)

Question 6

What is metabolism of bone like? How does this impact tx of an infection?

Answer 6

Poor - hard to fight infection

• not very cellular
• culture bugs and choose appropriate Abx

Question 7

What does bone pathology always lead to?

Answer 7

BOTH
> bone loss (lysis)
> bone formation
(= same response to tumour/infection etc.)

Question 8

Dxx for bone diseae

Answer 8

• Rads always
• Culture and sensitivity (when swabbing tracts, must get >2/3 up the tract before skin commensals not interfering)
• Biopsy for C+S
• radionucleatide scan (deermine high levels of bone activity)

Question 9

Tx osteomyelitis

Answer 9

• early intervention BS
• change based on C+S
• conider local delivery (esp gentamycin)
• surgical debridement, immobilisation and lavage
• rehabilitation of entire limb

Question 10

Ddx for osteomyelitis on rads?

Answer 10

Osteosarcoma

Question 11

What tye of joint neoplasm may cause eroisin?

Answer 11

Synovial sarcoma - eating away at talus

Question 12

Common presentation of osteosarcoma?

Answer 12

• old, large breed dog
• unilateral lamenss, chronic duration
• unesponsive to analgesia, excercise restriction
• pain on deep palpation of distal radius (common predilection site) and welling

Question 13

Work up of potential osteosarcoma case

Answer 13

• clinical evaluation
• radiograph
• swab tracts
• Biopsy (Jamshidi, no. of planes but minimal skin incisions) definitive dx based on biopsy and culture
• staging and evaluation of prrognosis

Question 14

Outline bone biopsy technique

Answer 14

• Jamshidi needle or Michelle trephine
• through centre of lesion (not margins)
• sample cortex and medulla
• multiple samples (same skin incision)
• cytology and cultulre
• ID landarks for pathologist (core v outside of lesion)

Question 15

Are osteosarcomas common?

Answer 15

Dogs yes

- cats and horses v rare

Question 16

Ddx osteosarcoma?

Answer 16

• feline TB

- calcinosis circumscripta

Question 17

Decision making aspects of osteosarcoma tx?

Answer 17

• unremittengly painful if left aloone (analgesia wont do)
• must tx 1* successfully
• consider 2* spread (nearly all osteosarcs have micromets in the lung at time of dx)
• client communication (many people find skeletal tumour hard to understan implications)

Question 18

Tx osteosarcoma? Prog?

Answer 18

• amputation (4mo)
• amputation + chemo (12-14mo)
• limb sparing + chemo (12-14)
• radiotx (palliative only)
• NSAIDs/bisphosphonates (pallliative only)
• euthanasia
  > >talk to owners repeatedly!

Question 19

What are the potential prsentations of osteosarcomas?

Answer 19

• lytic
• proliferative
• destructive

Question 20

When can osteosarcoma and osteomyelitis affect animals?

Answer 20

Any age throughout its life (generally >1year)