Multiple Myeloma and Bone Pain Flashcards
What is multiple myeloma?
https://www.youtube.com/watch?v=ghvoKhpAc64
Myeloma is a malignant disease of bone marrow plasma cells. There is a clonal expansion of abnormal, proliferating plasma cells producing a monoclonal paraprotein, mainly IgG or IgA, and rarely IgM and IgD.
The paraproteinaemia may be associated with excretion of light chains in the urine (Bence Jones protein), which are either kappa or lambda.
What age group does multiple myeloma normally affect?
Elderly
What is the peak age at which MM presents?
70 years
Who is it more common in; Africans or Caucasians?
Africans - 2:1
What cells are affected by neoplastic changes in multiple myeloma?
Plasma cells
What do neoplastic myeloma cells produce?
Monoclonal paraproteins
What proportion of multiple myeloma cases have IgG paraproteins?
60%
What proportion of multiple myeloma cases have IgA paraproteins?
20%
Why does osteolysis occur in multiple myeloma?
The osteolytic destruction of the axial skeleton (sites of haemopoiesis in adults) results from malignant plasma cells stimulating osteoclasts to erode bone.
For some time it has been recognised that chemical messengers (cytokines) produced from the interaction of malignant plasma cells with their microenvironment stimulate the osteoclast activity. Such cytokines were known as osteoclast activating factors (OAFs) and are now known to include interleukin-1 and -6.
What may bee seen on blood film in multiple myeloma?
Rouleaux formation - as a consequence of the paraprotein and circulating plasma cells in the aggressive plasma cell leukaemia variant of myeloma.
What type of anaemia occurs in multiple myeloma?
Normocytic normochromic
What can be found in the urine in someone with multiple myeloma?
Bence-Jones Proteins
What are the following?
Roleaux formations
Why are bence jones proteins found in the urine?
Found in urine as a result of decreased kidney filtration capabilities due to renal failure, sometimes induced by hypercalcemia from the calcium released as the bones are destroyed or from the light chains themselves
What are the most commonly affected bones in multiple myeloma?
- Spine
- Skull
- Long bones
- Ribs
What does adhesion of bone marrow stromal cells to myeloma cells result in?
Produces cytokines, which:
-
Stimulates the production of RANKL, IL-6 and also VEGF -> angiogenesis
- RANKL -> stimulates osteoclastic osteolysis.
- OPG levels reduced -> reduced inhibition of osteoclastic activity
- Paracrine secretion of endothelin 1 and PTH-rp -> increases osteoclastic activity.
What are symptoms of multiple myeloma?
- Bone pain
- Symptoms of anaemia
- Recurrent infections
- Symptoms of renal failure
- Symptoms of hypercalcaemia
- Symptoms of hyperviscosity and bleeding - rare
- Weight loss
What is the most common type of bone pain?
Backache
What are symptoms of hypercalcaemia?
Bones, stones, groans, thrones (plenty pish but nae shite) and psychiatric overtones:
- Abdominal pain
- Vomiting
- Constipation
- Polyuria
- Polydipsia
- Depression
- Anorexia
- Weight loss
- Tiredness
- Weakness
- Hypertension
- Confusion
- Pyrexia
- Renal stones
- Renal failure
- Cardiac arrest
Why does bone pain occur in MM?
Malignancy, whether primary or metastatic, changes the osteoblastic/osteoclastic balance. This results in either lytic lesions or abnormally weakened bone that is subject to microfractures.
Increased bone turnover can also produce pain, similar to the ‘growing pains’ of rapid growth in adolescence.