Osteomyelitis and Osteosarcoma Flashcards
What common disease processes happens in bone to cause lameness?
Developmental, Endocrine, Infectious, Metabolic, Neoplastic
Trauma - fractures
What are common disease processes in joints?
Degenerative and Inflammatory
Define osteomyelitis
Infection of the cortical bone and medullary cavity
Common in adults
Define osteitis
Inflammation of the cortex without involvement of the red or yellow bone marrow; can be septic or aseptic
(restricted to cortex)
Describe the acute presentation of osteomyelitis
- Occurs in large and small animal
- Single limb lameness rapid onset, short duration
- Often history of laceration or surgery - cut down to bone
What do you usually see on clinical exam for osteomyelitis in an acute presentation?
Heat, pain, swelling on palpation of bones
Joint structures may be normal
Febrile - fever
Wound with bone underneath it
What is the plan for an acute presentation for osteomyelitis?
Sedation, Analgesia, Flush (sterile, at 2L minimum)
AB in horses (lot of new bv)
Describe the chronic presentation of osteomyelitis?
- large and small animal
- Moderate/intermittent lameness of days/weeks duration
- Often a history of laceration or surgery
What are the clinical signs for osteomyelitis in a chronic presentation?
- possible heat, pain, swelling on palpation of bones
- joint structure may be normal
- pain, discharge, sinus tract formation
- pathological fracture (becomes acute issue)
What can a fistula discharging pus could indicate a problem with in relation to fractures?
Reaction - slow infection from a plate put in for a fracture
In bone disease, the combination of pathogenic process and bone’s reaction leads to what two things?
- Bone loss (lysis) —> see lysis as ↑soft tissue density
- Bone formation
(Infection present drives resorption of bone and so new bone is laid around it)
What are some diagnostic options/plans for bone disease?
- Radiography*
- Culture and sensitivity (tracts? pieces of necrotic material)
- Biopsy (chronic osteomyelitis and osteosarcoma will look similar on radiograph; this helps distinguish between the two)
- Radionuclide scan
Where do you need to sample from when culturing from tracts?
Right at the bottom of the tract for offending bac (top would be commensal bac)
What is Dscospondylitis?
Infection of the spinal vertebrae + intervertebral discs
-A form of vertebral osteomyelitis-distinguished by the involvement of intervertebral discs, adjacent vertebral bony endplates and vertebral bodies
If see changes - use a radionuclide scan
What is the treatment for osteomyelitis?
- Early intervention with broad spectrum antibiotics (change on basis of culture and consider local delivery-long term)
- Surgical debridement, immobilization, lavage
- Rehabilitation of entire limb
Why is it important to get a bone biopsy when presented with radiographic appearance of osteomyelitis?
Osteosarcoma and chronic osteomyelitis are radiographically similar (combination of lysis and formation in the bone)
RADS: with lysis and aggressive new bone formation (CHECK RADS IN PICTURE ROUND)
With suspected bone neoplasm, what should be included in the investigation?
- Clinical evaluation (lymph nodes- metastasis?, degree of disability)
- Radiography - local and thoracic
- Swab tracts, C&S on samples
- Biopsy (jamshidi needle (core out of bone, get a number of planes)
- Definitive dx based on biopsy or culture
- Staging/evaluation of prognosis
Why is it important to get multiple planes of the lesion in a bone biopsy?
You need to get a representative sample of the lesion in order to help the pathologist make a definitive diagnosis
What techniques do you usually use for bone biopsy?
a) How?
Jamshidi needle or Michelle trephanie (more rare)
a) Through the centre of lesion-sampling both cortex and medulla - make sure to incise skin before!
Cytology and culture!
What is the issue with cases of osteosarcoma?
Usually v v painful and normal analgesia won’t do
- usually secondary spread to lungs (micro mets)
- progress to lameness to life ending disease in 3 weeks
Name 3 different types of osteosarcoma presentations?
Lytic, Proliferative, destructive
What are some treatment options for osteosarcoma?
- Amputation (4 months) - treats 1° problem + but still have mets
- Amputation and Chemo (control mets) (12-14 months) GOLD S
- Limb sparing and Chemo (12-14 months) (remove tumour without removing limb - donor dog’s radius + plate+ pins)
- Radiotherapy (palliative only)
- NSAIDs/Bisphosphonates (palliative only)
- Euthanasia
