Myeloma Flashcards
what is myeloma?
cancer of the plasma cells (a type of B lymphocyte that produce antibodies)
specific type of plasma cell results in large quantities of a single type of antibody being produced
what is multiple myeloma?
where the myeloma affects multiple areas of the body
what is Monoclonal gammopathy of undetermined significance (MGUS)
there is an excess of a single type of antibody or antibody components without other features of myeloma or cancer.
often an incidental finding in an otherwise healthy person and as the name suggests the significance is unclear
may progress to myeloma and patients are often followed up routinely to monitor for progression
what is smouldering myeloma?
and what is Waldenstrom’s macroglobulinemia?
where there is progression of MGUS with higher levels of antibodies or antibody components
It is premalignant and more likely to progress to myeloma than MGUS.
Waldenstrom’s macroglobulinemia is a type of smouldering myeloma where there is excessive IgM specifically.
what is the pathophysiology of myeloma?
genetic mutation causing a specific type of plasma cell rapidly and uncontrollably multiply
they produce 1 type of antibody aka immunoglobulins
what are antibodies/immunoglobulins?
what are the 5 main types
complex molecules made up of two heavy chains and two light chains arranged in a Y shape.
help the immune system recognise and fight infections by targeting specific proteins on the pathogen
come in 5 main types: A, G, M, D and E
what will you find when you measure immunoglobulins in a patient with myeloma?
one of those types either A, G, M, D & E, will be significantly abundant.
More than 50% of the time this is immunoglobulin type G (IgG).
what is a monoclonal paraprotein?
single type of antibody that is produced by all the identical cancerous plasma cells
what is a Bence Jones protein and where is it found?
part (subunit) of the antibody called the light chains
can be found in the urine of many patients with myeloma
why do patients get anaemia in myeloma?
cancerous plasma cells invade the bone marrow - BM infiltration
causes suppression of development of other blood cell lines = anaemia, neutropenia, thrombocytopenia
what is myeloma bone disease?
decreased osteoclast activity and suppressed osteoblast activity
osteoclasts absorb bone and osteoblasts deposit bone
more bone is being reabsorbed than constructed
caused by cytokines released from the plasma cells and stromal cells when they are in contact with plasma cells
where are some common places for myeloma bone disease to happen?
skull
spine
long bones
ribs
what are osteolytic lesions
abnormal bone metabolism is patchy, meaning that in some areas the bone becomes very thin whereas others remain relatively normal.
osteolytic lesions are the patches of thin bone
what happens at areas with osteolytic lesions?
weak points = pathological fractures
eg vertebral body in spine may collapse or femur may break under minimal force
why do patients with myeloma have high blood calcium - hypercalcaemia?
osteoclast activity causes a lot of calcium to be reabsorbed from the bone into the blood = hypercalcaemia
what are plasmacytomas?
can develop with multiple myeloma
individual tumours made up of cancerous plasma cells
can occur in bones, replacing normal bone tissue or can occur outside bones in the soft tissue of body
Patients with myeloma often develop renal impairment. what are some factors that impact this?
- High levels of immunoglobulins (antibodies) can block the flow through the tubules
- Hypercalcaemia impairs renal function
- Dehydration
- Medications used to treat the conditions such as bisphosphonates can be harmful to the kidneys
describe hyperviscocity
plasma viscosity increases when then are more proteins in the blood
These are proteins like immunoglobulins and fibrinogen, both of which increase with inflammation.
In myeloma there are large amounts of immunoglobulins in the blood causing the plasma viscosity to be significantly higher.
what are some issues caused by plasma viscosity?
- Easy bruising
- Easy bleeding
- Reduced or loss of sight due to vascular disease in the eye
- Purple discolouration to the extremities (purplish palmar erythema)
- Heart failure
what are the 4 key features of myeloma?
- C – Calcium (elevated)
- R – Renal failure
- A – Anaemia (normocytic, normochromic) from replacement of bone marrow.
- B – Bone lesions/pain
what are the risk factors for myeloma?
- Older age
- Male
- Black African ethnicity
- Family history
- Obesity
when should you suspect myeloma and what investigations should you do?
considering myeloma in anyone >60 with persistent bone pain, particularly back pain, or an unexplained fractures. Perform initial investigations:
- FBC (low white blood cell count in myeloma)
- Calcium (raised in myeloma)
- ESR (raised in myeloma)
- Plasma viscosity (raised in myeloma)
If any of these are positive or myeloma is still suspected do an urgent serum protein electrophoresis and a urine Bence-Jones protein test.
what initial investigations are done for myeloma? - BLIP
- B – Bence–Jones protein (request urine electrophoresis)
- L – Serum‑free Light‑chain assay
- I – Serum Immunoglobulins
- P – Serum Protein electrophoresis
bone marrow biopsy - to confirm dx
imaging - to assess for bone lesions - whole body MRI or CT or skeletal survey (in order of preference)
what are some x ray signs for myeloma?
- Punched out lesions
- Lytic lesions
- “Raindrop skull” caused by many punched out (lytic) lesions throughout the skull that give the appearance of raindrops splashing on a surface
what is the management of myeloma?
aim to control disease
1st line = combination chemotherapy
- Bortezomid
- Thalidomide
- Dexamethasone
stem cell transplantation can be used as part of clinical trial where patients are suitable
VTE prophylaxis with aspirin or LMWH - higher risk of thrombus development
how is myeloma bone disease managed?
- Myeloma bone disease can be improved using bisphosphonates - suppress osteoclast activity.
- Radiotherapy to bone lesions can improve bone pain.
- Orthopaedic surgery can stabilise bones (e.g. by inserting a prophylactic intramedullary rod) or treat fractures.
- Cement augmentation involves injecting cement into vertebral fractures or lesions and can improve spine stability and pain
what are some complications of myeloma?
- Infection
- Pain
- Renal failure
- Anaemia
- Hypercalcaemia
- Peripheral neuropathy
- Spinal cord compression
- Hyperviscocity
