Haematology - Plasma cell myeloma and Monoclonal Gammopathy of Uncertain Significance Flashcards
What immunoglobin is produced by myeloma cells?
One single type (eith IgG or IgA) which is known as paraprotein or M spike
What are Bence Jones proteins?
Urine monoclonal free light chains
What is -Lymphoplasmacytic lymphoma?
A type of non-Hodgkin lymphoma with IgM paraprotein that causes visual disturbances
aka Waldenstrom’s macroglobunlinaemia
What is the name of the premalignant condition that always precedes myeloma?
Monoclonal gammaopathy of uncertain significance (MGUS)
What are the two most significant risk factors for myeloma?
Obesity
Black > causasians/ asians
What are the diagnostic criteria for MGUS?
Serum Monoclonal-protein (often IgG)<30g/L
BM clonal plasma cells <10%
Asymptomatic
What is smouldering myeloma?
Serum M-protein (often IgG) >30g/L
BM clonal plasma cells >10%
Asymptomatic
What % of plasma cells is there in symptomatic multiple myeloma?
>10%
What is the most notable interaction of myeloma cells with the bone marrow micro-environment?
Produce RANK ligand which stimulates osteoclasts to cause bone resorptions
What is the incidence of IgM myeloma?
Very rare (<1% of myelomas)
What does CRAB stand for in myeloma diagnosis?
Calcium (hypercalcaemia, >2.75)
Renal (creatinine >177/ eGFR <40)
Anaemia
Bone disease (see lytic lesions)
What is the most common and 2nd most common cytogenetic abnormality in myeloma?
- Hyperdiploid karyotype
- IgH gene rearrangement
What are the 3 2014 Myeloma Defining Events
BM plasma cells >60%
involved:uninvolved FLC ratio >100
>1 focal lesion on MRI
Which part of the skeleton is affected by myeloma?
Proximal skeleton (spine, skull, knees)
Where are myeloma patients most likely to feel pain?
Back, chest wall, pelvis
What % of myeloma patients present with bone disease?
80%
What scan is necessary to detect bone lesions in myeloma? What is gold standard
Whole body CT is first line (X ray is obsolete for this use)
PET scan can also be used
Gold-standard = whole body diffusion-weighted MRI as this shows active vs treated disease
What are the 2 most likely emergency presentations of myeloma?
Cord compression
Hypercalcaemia
What 5 investigations to diagnose myeloma?
Serum protein electrophoresis (dense bands of IgG or IgA monoclonal proteins)
blood film - rouleaux stacks
bence jones proteins in urine
high ESR
more than 10% plasma cells in BM biopsy
What is the best way to treat cord compression in myeloma?
Dexamethosone
Radiotherapy
What risk does myeloma present to the kidney?
Cast nephropathy - FLCs and Bence Jones proteinuria cause proximal tubule cell injury
How should myeloma kidney disease be treated in an emergency?
Bortezomib-based therapy (proteasome inhibitor) is the cornerstone of myeloma kidney disease treatment - once the patients can become independent from dialysis their outcomes improve dramatically
How does myeloma affect immunity?
Serum levels of normal Igs reduced
BM micro-environment interference also impairs myeloid, T and NK cells
What is tested for in BM biopsy in suspected myeloma?
Immunohistochemistry for CD138 - specific for myeloma cells in BM