Haematology 11 - Plasma cell myeloma and Monoclonal Gammopathy of Uncertain Significance Flashcards

1
Q

What immunoglobin is produced by myeloma plasma cells?

A

One single type (either IgG or IgA) which is known as paraprotein or M spike

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2
Q

What are Bence Jones proteins?

A

Urine monoclonal free light chains

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3
Q

What is Waldenstrom’s-Lymphoplasmocytic lymphoma?

A

A lymphoplasmocytic lymphoma with IgM paraprotein that causes visual disturbances

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4
Q

What is the name of the premalignant condition that always precedes myeloma?

A

Monoclonal gammopathy of uncertain significance (MGUS)

However, most individuals with MGUS will NOT develop myeloma

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5
Q

What are the two most significant risk factors for myeloma?

A

Obesity
Black > causasians/ asians

Also age - peaks between 84-85

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6
Q

What are the diagnostic criteria for MGUS?

A

Serum M-protein <30g/L
BM clonal plasma cells <10%
Asymptomatic (no lytic bone lesions, no myeloma-related organ damage)
No evidence of other B-cell proliferative disorder

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7
Q

What is smouldering myeloma?

A

Serum M-protein >30g/L
BM clonal plasma cells >10%
Asymptomatic

Essentially in between MGUS and symptomatic myeloma

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8
Q

What % of plasma cells is there in symptomatic multiple myeloma?

A

> 10%

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9
Q

What is the most notable interaction of myeloma cells with the bone marrow micro-environment?

A

Produce RANK ligand which stimulates osteoclasts to cause bone resorptions

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10
Q

What is the incidence of IgM myeloma?

A

Very rare (<1% of myelomas)

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11
Q

What does CRAB stand for in myeloma diagnosis?

A

Calcium (hypercalcaemia, >2.75)

Renal (creatinine >177/ eGFR <40)

Anaemia

Bone disease (see lytic lesions)

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12
Q

What is the most common and 2nd most common primary cytogenetic abnormality in myeloma?

A
  1. Hyperdiploid karyotype

2. IgH gene rearrangement (t(11:14) IGH/CCND1)

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13
Q

What are the 3 2014 Myeloma Defining Events

A

BM plasma cells >60%
involved:uninvolved FLC ratio >100
>1 focal lesion on MRI

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14
Q

Which part of the skeleton is affected by myeloma?

A

Proximal skeleton (spine, skull, knees)

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15
Q

Where are myeloma patients most likely to feel pain?

A

Back, chest wall, pelvis

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16
Q

What % of myeloma patients present with bone disease?

A

80%

These are osteolytic lesions - never osteoblastic

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17
Q

What scan is necessary to detect bone lesions in myeloma?

A

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

18
Q

What are the 2 most likely emergency presentations of myeloma?

A

Cord compression

Hypercalcaemia

19
Q

What tests should be done to diagnose myeloma?

A
First: 
Serum protein electrophoresis 
Serum free light chains 
Next: 
Bone marrow aspirate and biopsy for immunohistochemistry 
FISH (for prognostic)
20
Q

What is the best way to treat cord compression in myeloma?

A

Diagnosis and treatment within 24 hours, do MRI scan

Dexamethasone
Radiotherapy

21
Q

What risk does myeloma present to the kidney?

A

Cast nephropathy - FLCs and Bence Jones proteinuria cause proximal tubule cell injury

Other contributing factors may include hypercalcaemia, use of diuretics, infections etc

22
Q

How should myeloma kidney disease be treated?

A

TREAT AS AN EMERGENCY

Bortezomib-based therapy is the cornerstone of myeloma kidney disease treatment - once the patients can become independent from dialysis their outcomes improve dramatically

23
Q

How does myeloma affect immunity?

A

Serum levels of normal Igs reduced

BM micro-environment interference also impairs myeloid, T and NK cells -> leads to chest infections and remarkably high levels of herpes zoster reactivation

Chemo also impairs immune response

24
Q

What is tested for in BM biopsy in suspected myeloma?

A

Immunohistochemistry for CD138 - specific for myeloma cells in BM

25
Q

What test can detect cytogenetic abnormalities of prognostic significance in myeloma?

A

FISH

26
Q

What are the 3 parameters in the international staging system for myeloma?

A

Serum beta microglobulin

Cytogenetic risk

LDH

27
Q

How does AL amyloidosis link to myeloma?

A

Misfolded FLCs aggregate into amyloid in target organs

Amyloidogenic potential/propensity to misfold of these light chains is more important than their amount

28
Q

How does amyloidosis affect the kidney?

A

Nephrotic syndrome

29
Q

Give 5 features of the clinical presentation of AL amyloidodis?

A
Nephrotic syndrome
Unexplained heart failure
Sensory neuropathy
Abnormal liver function tests
Macroglossia
30
Q

What is MGRS?

A

Monoclonal gammaopathy of Renal significance

31
Q

How is MGRS defined?

A
  1. One or more kidney lesions caused by mechanisms related to the produced monoclonal immunoglobulin (Ig)
  2. The underlying B cell clone does not cause tumor complications or meet current hematological criteria for immediate specific therapy
32
Q

How do proteasome inhibitors work in multiple myeloma

A

Proteasomes are involved in removing misfolded proteins

If you prevent this, the amount of misfolded protein produced in myeloma will overwhelm the cell and cause apoptosis

33
Q

Which monoclonal antibody is used in myeloma treatment?

A

Anti-CD38 (daratumumab)

34
Q

What is the difference between a pre-myeloma MGUS and pre-lymphoma MGUS?

A

Pre-myeloma: IgG/A-producing B cells

Pre-lymphoma: IgM-producing B cells

35
Q

What are the 3 risk factors for MGUS progression?

A
  1. Non-IgG M spike
  2. M spike >15g/L
  3. Abnormal serum free light chain ratio
36
Q

What are the clinical effects of myeloma due to?

A
  1. BM microenvironment interaction

2. Circulating paraprotein

37
Q

What is the cause of dinovo angiogenesis in myeloma?

A

CD34 expression on myeloma cells promotes angiogenesis

38
Q

What type of nephropathy does myeloma cause?

A

Cast nephropathy

39
Q

What are the first investigations to be done in suspected myeloma?

A

Serum protein electrophoresis

Serum free light chains

40
Q

What condition can produce MGUS/ myelomas part of its progression?

A

AL amyloidosis

41
Q

Recall 6 options for myeloma therapy

A
  1. Alkylators (eg cyclophosphamide)
  2. Steroids (eg dex + pred)
  3. Thalidomide
  4. Cereblon-binding drugs
  5. Proteosome inhibitors
  6. Anti-CD38 (daratumumab)
42
Q

How do cereblon-binding drugs work?

A

Decrease levels of IRF4 –> decreased myc –> myeloma cell death