Multiple Myeloma (MM)

Exam Cram

• Multiple myeloma is a Plasma cell dyscrasia, plasma cells are mature B cells that produce antibodies

• Presentation (CRAB): hypercalcaemia, renal failure, anaemia, boney pain

• Diagnosis: bone marrow aspirate, raised serum free light chains or > 1 boney lesion on MRI (+ SLIM-CRAB)

• Management: CHOP regime (thalidomide + cyclophosphamide + pred), blood transfusions, bone marrow transplant

OUtline

Presentation

History

• 60yrs, subacute presentation

• Constipation, tiredness, reduced exercise tolerance

• Low trauma fracture or back pain

Examination

• Boney tenderness

Investigations

• AKI

• Anaemia

• Hypercalcaemia

• Raised blood protein electrophoresis

• Raised urinary bence jones proteins

• Imaging (XR, CT, MRI): osteoblastic lesions

Diagnosis

Screening test: raised protein electrophoresis or bence jones proteins

Diagnostic criteria: IMWG Criteria- 2014 > 0

• Clonal Bone Marrow Cells > 10%

• Bone marrow aspirate: > 60% clonal plasma cells

• Raised serum free light chains (kappa or lambda)

• MRI: > 1 focal lesion that is > 5mm

Differentials: malignancy of unknown primary

Management

First line therapy (transplant eligible)

1. Chemotherapy induction: DVTD x4 cycles

2. Bone marrow transplant (Autograft)

3. Chemotherapy consolidation: DVTD x2 cycles

4. Lenalidomide maintenance

DVTB

• D- Daratumumab: CD38 monoclonal antibody that targets the CD38 protein on myeloma cells allowing immune system to kill them

• V- Bortezomib: A proteasome inhibitor that blocks protein breakdown in cancer cells, causing them to die

• T - Thalidomide

• D - Dexamethasone: suppresses immune system

Adjunct

4. • RBC transfusions

   • Local radiotherapy

*

SLIM CRAB

• S- bone marrow plasma cells > 60%

• LI: light chains > 100, SFLC ratio > 100

• M- > 1 focal lesion on MRI 

• C- Hypercalcaemia > 2.75mml/l

• R- Renal failure: Cr > 177

• A- Anaemia: Hb < 100

• B- > 0 lytic lesion on XR/ PET/ CT

MGUS (Monoclonal Gammopathy of Uncertain Significance)

Definition

• Paraprotein < 30 g/l

• Bone marrow: plasma cells < 10%

• Nil end organ damage: renal, skeletal, bone marrow impairment- nil CRAB

Prognosis: 1% annual progression to myeloma. 

References and Resources

1. https://www.myeloma.org/international-myeloma-working-group-imwg-criteria-diagnosis-multiple-myeloma

2. https://haembase.com/myeloma

2024