Myeloma

Overview:

• Is part of a spectrum of diseases
• Characterised by the presence of a paraprotein in the serum:
• Is produced by abnormal, proliferating plasma cells that produce (most often) IgG or IgA (and rarely IgD)

• The paraproteinaemia may be associated with the excretion of light chains in the urine (known as Bence-Jones protein)

Clinical features:

Is a disease of the elderly (median age at presentation being 60 years)

It is a complex illness which represents the inter-relationship between:

• Bone destruction:
• Vertebral collapse (which can cause spinal cord compression)
• Fractures
• Hypercalcaemia
• Bone marrow infiltration:
• Pancytopenia
• Production of paraprotein which may (rarely) result in symptoms of hyperviscosity
• Renal impairment owing to a combination of:
• Deposition of light chains
• Hypercalcaemia
• Hyperuricaemia

Symptoms:

• Bone pain
• Symptoms of anaemia
• Recurrent infections
• Symptoms of renal failure (e.g. pruritus, anorexia, lethargy)
• Symptoms of hypercalcaemia

Investigations:

FBC:

• All values are normal or low

ESR:

• Raised

Blood film:

• May be rouleaux formation as a consequence of the paraprotein

U&Es:

• May be evidence of renal failure

Serum Ca²⁺:

Normal or raised

Serum ALP:

Usually normal

Total protein:

Normal or raised

Serum albumin:

Normal or low

Protein electrophoresis:

Characteristically shows a monoclonal band (paraprotein)

Uric acid:

Normal or raised

Skeletal survey:

May show characteristic lytic lesions, most easily seen in the skull

24-hour urine:

To assess light-chain excretion

Bone marrow aspirate:

Shows characteristic infiltration by plasma cells

General treatment:

Anaemia corrected

Infection treated

Bone pain can be helped most quickly by radiotherapy

Pathological fractures can be prevented by prompt orthopaedic surgery with pinning of lytic bone lesions seen on the skeletal survey

Renal failure needs to be assessed and may need long-term dialysis

Patients with spinal cord compression due to Myeloma are treated with dexamethasone, followed by radiotherapy to the lesion delineated by an MRI scan

Specific treatment:

• The use of alkylating agents (e.g. melphalan, cyclophosphamide) in conjunction with prednisolone has improved the median survival from 7 months to 2 years

Prognosis:

• Patients presenting with anaemia and renal failure have a very poor prognosis, with 50% dying within 9 months
• Patients without these 2 features at presentation survive for about 2 years