Haematology - myeloma Flashcards
What is myeloma? Multiple myeloma?
Cancer of plasma B cells
Multiple myeloma is where the myeloma affects multiple areas of the body.
What is MGUS?
Monoclonal gammopathy of undetermined significance (MGUS)
Where there is an excess of a single type of antibody or antibody components without other features of myeloma or cancer
Often an incidental finding and may progress to myeloma
What is smouldering myeloma?
Progression of MGUS with higher levels of antibodies or antibody components
It is premalignant and more likely to progress to myeloma than MGUS
What is a type of smouldering myeloma?
Waldenstrom’s macroglobulinemia - has excessive IgM
What is the pathophysiology of myeloma?
Genetic mutation causing rapid and uncontrolled division of a specific type of plasma B cells
Plasma cells usually produce immunoglobulins (A,G,M,D,E) so the levels of one of these types of immunoglobulins will be high in myeloma
More than 50% of the time it is IgG that is raised
What are the four key features of myeloma?
CRAB mnemonic
C- calcium raised
R- renal failure
A - anaemia
B - bony lesions/pain
It can also cause raised plasma viscosity
What are the risk factors for myeloma?
Older age Male Black African ethnicity Family history Obesity
What FBC abnormalities does myeloma cause?
Cancerous plasma cells infitrate the bone marrow suppressing the development of other blood cell lines leading to anaemia (low red cells), neutropenia (low neutrophils) and thrombocytopenia (low platelets).
There is a low WCC in myeloma
How does myeloma cause bone disease?
A result of increased osteoclast activity and suppressed osteoblast activity.
Common places for myeloma bone disease to occur are the skull, spine, long bones and ribs
Can cause pathological fractures e.g. vertebral fracture
Osteoclast breakdown of bone results in raised calcium
How does myeloma cause renal impairment?
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
How does myeloma cause hyper- viscosity?
Plasma viscosity increases with more proteins in the blood
In myeloma there are large amounts of immunoglobulins in the blood
What is the impact of hyperviscosity seen in myeloma?
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
In who should myeloma be suspected
Consider myeloma in anyone over 60 with persistent bone pain, particularly back pain, or an unexplained fractures.
Initial investigations in suspected myeloma
FBC (low WCC)
Calcium (raised in myeloma)
ESR (raised in myeloma)
Plasma viscosity (raised)
If any of these are positive, do an urgent serum protein electrophoresis and a urine Bence-Jones protein test
Next step investigations
Bence-Jones protein (urine electrophoresis)
Serum free light-chain assay
Serum immunoglobulins
Serum protein electrophoresis
Bone marrow biopsy is necessary to confirm diagnosis
Imaging required to assess for bony lesions (full body MRI is first line)
