Week 9 - bone pain Flashcards
Describe the basic epidemiology of Paget’s disease. (LO1)
- Second most common metabolic bone disease.
- More common in males.
- Unusual in <40s.
Describe the pathophysiology of Paget’s disease. (LO1)
- Increased bone cell activity.
- Osteoclasts are larger in size, therefore, resorb more bone.
- This leads to osteoblasts laying down bone in a haphazard way resulting in poor bone architecture.
- As a result, we see expansion of poor quality bone.
- The marrow is replaced with fibrous tissue (which isn’t as strong) and blood vessels - leading to the bone sometimes feeling warm due to increased blood flow.
Which bones are usually affected by Paget’s disease? (LO1)
Normally only one bone is affected.
- Femur.
- Spine.
- Skull.
- Sternum.
- Pelvis.
- Any bone in the body can be affected.
List some neurological symptoms of Paget’s disease. (LO1)
- Obstructive hydrocephalus - fluid not circulating around the brain.
- Cranial nerve palsies - nerve going through the skull not working.
- Deafness - if the skull expands.
- Paraplegia or quadriplegia - if the spine is affected.
- Tinnitus.
List some investigations for Paget’s disease. (LO1)
- Plain radiographs.
- CT.
- MRI.
- PET CT.
- Isotope bone scans.
List some presentations of Paget’s disease. (LO1)
On examination, the affected bone will be:
- Warm - due to increased blood flow.
- Tender - due to periosteum being stretched.
- Deformed.
Briefly describe the genetic factor associated with Paget’s disease. (LO1)
- There is a small genetic link with a defect in the SQSTM1 gene.
- However, it is unknown what triggers this defect.
List the complications caused by expansion of the pelvis due to Paget’s disease. (LO1)
- Pain in the hip joint.
- Bone deformity.
- Bone pain.
- Increased risk of fracture.
- Sclerotic and lytic areas on x-rays.
- Osteoarthritis in neighbouring joints.
Rare:
- Cardiovascular symptoms.
- Metabolic symptoms.
- Neoplasia.
Describe the findings of an x-ray in Paget’s disease. (LO1)
- Bones expanded.
- Cortical thickening.
- Mixture of sclerotic and lytic areas.
Describe the management of Paget’s disease. (LO1)
- Zoledronate 5mg - reduce osteoclast function.
- Analgesia - to relieve symptoms.
- Vitamin D.
- Physiotherapy.
- Surgery - to repair fractures, replace joints or for spinal stenosis.
Describe the basic epidemiology of bone metastases. (LO2)
- 400,000 diagnoses of bony metastases are made in the US annually.
- The general incidence of advanced malignant tumours with bone metastasis is 30-75%.
- The presence of bone metastases indicates a poor prognosis.
List the most common cancers to metastasise to bones. (LO2)
Most common primary tumours for bone metastases are organs that naturally lie near bone:
- Prostate cancer - 65-75% of prostate cancer cases will involve metastasis to the bone.
- Breast cancer - 65-75%.
- Thyroid cancer - 60%.
- Lung cancer - 30-40%.
- Bladder cancer - 40%.
- Renal cell carcinoma - 20-25%.
- Melanoma - 14-45%.
List the three types of bone metastases. (LO2)
- Osteolytic.
- Osteoblastic.
- Mixed.
Describe osteolytic bone metastases. (LO2)
- Mediated by osteoclasts which break down the bone matrix.
Which cancers is osteolytic bone metastases more likely to be found in? (LO2)
- Multiple myeloma.
- Renal cell carcinoma.
- Melanoma.
- Breast cancer.
Describe osteoblastic bone metastases. (LO2)
- New bone is laid down by osteoblasts, forming sclerotic lesions.
- This is not always preceded by bone resorption.
Which cancers is osteoblastic bone metastases more likely to be found in? (LO2)
- Prostate cancer.
- Carcinoid.
- Small cell lung cancer.
Describe mixed bone metastases. (LO2)
- Both destruction and deposition of bone.
Which cancers is mixed (lytic+blastic) bone metastases more likely to be found in? (LO2)
- Breast cancer - 15-20% have a mixed type of bone metastasis.
- GI cancers.
- Squamous cancers.
List the three mechanisms of spread of bone metastases. (LO2)
- Epithelial-mesenchymal transition.
- Micro-environmental support.
- Vascular adhesion and extravasation.
All of these work together to allow the tumour to spread.
Describe epithelial-mesenchymal transition as a mechanism of spread for bone metastases. (LO2)
- Where epithelial cells transition into a mesenchymal cell.
- Epithelial cells have tight junctions which fix them to neighbouring cells.
- When they transition to mesenchymal cells, they lose the junctions making them more mobile, i.e. they can migrate.
Describe micro-environmental support as a mechanism of spread for bone metastases. (LO2)
- The seed and soil hypothesis states that the “soil”, which is distant tissue, bone in this case, is fertile ground for growth of the “seed” which is the primary cancer.
Describe vascular adhesion and extravasation as a mechanism of spread for bone metastases. (LO2)
- Cancer cells can interact with the endothelium, causing extravasation.
Describe the presentation of bone metastases. (LO2)
- No specific presentation.
- Usually diagnosed on the staging scans/follow-ups for the primary cancer.
- Main symptom is non-specific pain.
- Neurological symptoms can also occur if the spine is involved.
- The severity of pain can be affected by:
- Is a nerve being compressed?
- Is the bone metastasis causing damage to a nearby structure?
- The location of the bone metastasis.