Monday, 18 October 2010

MRCP revision battle 33.1: Myeloma

So today is going to be a galavant through the world of paraproteinaemias, taking in 4 of the top 6 causes (myeloma, Waldenstrom's, MGUS and amyloid; lymphoma/leukaemia related are not discussed, nor is heavy chain disease)

While on the topic of paraproteinaemia is seems appropriate to cover hyperviscosity syndrome, which lends itself to a quick forray into polycythaemia and then on to two completely random topics to round off the day.


MRCP revision battle 33.1: Myeloma
MRCP revision battle 33.2: Hyperviscosity syndrome

MRCP revision battle 33.3: Waldenstrom's macroglobulinaemia
MRCP revision battle 33.4: MGUS
MRCP revision battle 33.5: Amyloidosis
MRCP revision battle 33.6: Polycythaemia
MRCP revision battle 33.7: Levels of evidence
MRCP revision battle 33.8: Holmes Adie pupil

MRCP revision battle 33.1: Myeloma

Myeloma is a malignant monoclonal proliferation of plasma cells.
The commonest subclass is IgG (IgG>IgA>IgM)

  • osteolytic bone lesions --> backache/pathological fractures
  • symptoms of hypercalcaemia
  • bacterial infections due to immunoparesis
  • renal impairment due to light chains

  • Bloods:
    • normocytic normochromic anaemia
    • rouleaux on blood film
    • raised calcium (40%)
    • raised urea and creatinine
    • raised ESR
  • Urine
    • Bence Jones proteins (=free serum light chains) in urine (66%)
  • XR
    • ?pepper pot skull, vertebral collapse

The diagnostic criteria for myeloma is:
  1. monoclonal protein band in serum or urine electrophoresis
  2. increased plasma cells on BM biopsy
  3. evidence of end organ damage from myeloma

    • supportive
    • chemo
      • younger patients: aggressive (VAD - vincristine, adriamycin, dexamethasone)
      • older patients: less aggressive (CDT - cyclophosphamide, dexamethasone, thalidomide)

    Complications of myeloma include:
    • Hyperviscosity syndrome
      • Hyperviscosity syndrome occurs most commonly in IgM myeloma (IgM>IgA>IgG)
      • Transfusions should be avoided in hyperviscosity syndrome.
    • hypercalcaemia
    • spinal cord compression
    • acute renal failure
    • AL amyloidosis (15%)

    Survival with myeloma tends to be 3-4 yrs. 
    Higher beta 2 microglobulin implies a worse prognosis.

    Onwards for a bit more about hyperviscosity syndrome....