Define osteomyelitis
Infection of the bone tissue (cortical bone or medullary cavity)
Why are osteosarcoma and osteomyelitis sometimes hard to distinguish?
- Both present acutely- Both have soft tissue swelling- Similar radiographic features (lysis & proliferation)
In which dogs is osteosarcoma more common?
Older dogs & large breeds
Does osteosarcoma metastasis?
Yes - ~15% pulmonary metastases at time of diagnosis
Where in long bones does osteosarcoma occur?
Metaphysis
Most common musculoskeletal tumour?
Osteosarcoma
Does osteosarcoma cause lameness?
Yes - can be acute or chronic:- often VERY painful- can present w pathological fracture
What in the history may point more towards osteomyelitis than osteosarcoma?
History of recent wound, trauma or infection
What may we find on physical exam of a dog with osteosarcoma?
- Bone pain- Crepitus- Palpably soft cortex - Swelling in metaphysis
What may we see on radiographs of osteosarcoma?
- Osteolysis & proliferation- Mottling- Periosteal reaction- Monostotic (one bone)- Indistinct border between normal & abnormal areas
Differentials for osteosarcoma? (6)
- Osteomyelitis- Other -sarcoma - Metastatic disease- Lymphoma- Multiple myeloma- Bone cyst
How to diagnose osteosarcoma?
- Radiography (limbs + thoracic for mets)- Lab: biochem (ALP), CBC, urinalysis- FNA or biopsy of bone lesion
Which is more accurate, FNA or biopsy of bone lesion for diagnosis of osteosarcoma?
Biopsy (but more technically challenging + risk of fracture)
What form of imaging can we use to highlight areas of high bone turnover when diagnosing / staging osteosarcoma?
Gamma scintigraphy
Treatment options for osteosarcoma?
- Analgesia as extremely painful- Biphosphonates (control bone turnover)- Amputation- Palliative radiation (slows bone turnover)
What is limb sparing surgery?
Removal of diseased portion of bone while preserving the limb
What does ITAP stand for?
Intraosseous endoprosthesis
Disadvantages of ITAP?
- Fracture risk- Infection- Failure of integration into bone / skin
Most common digit neoplasms in dogs? (4)
- SCC- Soft tissue sarc- MCT- Osteosarcoma
What % of digital masses are neoplasia?
60%
Treatment for digit neoplasia?
Amputation
Most common digit neoplasms in cats? (5)
- SCC- Fibrosarcoma- Adenocarcinoma- Osteosarcoma- Haemangiosarcoma
What is "lung-digit"?
Metastasis of 1* pulmonary mass -> digit in CATS
What radiographs to take of cats with digit neoplasia?
Thoracic (lung-digit!!) as well as paw
What is the next most common bone tumour after osteosarcoma?
Chondrosarcoma
How does metastatic rate differ between osteosarcoma & chondrosarcoma?
Much lower metastatic rate for chondrosarcomas
How to diagnose joint tumours?
- Imaging- Cytology (FNA / synovial fluid)- Biopsy + immunohistochemistry
How to differentiate between a bone & joint tumour on x-ray?
Bone tumours will not cross the joint - joint tumours will!
Name 2 primary neoplasms of the muscle
- Rhabdomyosarcoma- Haemangiosarcoma
How do primary muscle neoplams behave?
Like soft tissue sarcoma
Name 3 adipose neoplasms
- Benign lipoma- Infiltrative lipoma- Liposarcoma
Presentation of acute osteomyelitis?
- Systemic signs (pyrexia, leukocytosis)- Lameness- Swelling, pain on palpation+/- Draining sinus
Presentation of chronic osteomyelitis?
- Moderate, intermittent lameness- Pain - Often + draining sinus- Potential pathological fracture
How to diagnose osteomyelitis?
- Radiographs- FNA+/- Biopsy, C+S
Treatment for osteomyelitis?
- ABs (empirical Amoxiclav then based on C+S) for 6wks- Can give ABs locally (beads, sponges)- Remove structures maintaining biofilm e.g. implants & sequestra
Prognosis for osteomyelitis?
Variable but guarded (recurrence)