- Studies:
-
sed rate: is usually > 100 mm per hour;
- serum electrophoresis:
- finding of abnormal protein peak migrating w/ IgA or IgG fraction is diagnostic;
- an protein migrating w/ IgG or IgA bond in about 90 % of pts;
- major criteria for dx:
- monoclonal globulin spike > 3.5 g for IgG;
- monoclonal globulin spike > 2.0 g per 100 ml for IgA
-
hypercalcemia may occur in 20-40% of patients;
- this does not correlate with the amount of bony destruction;
- is more common in
renal insufficiency, & hence treatment may be difficult;
- combo of
calcitonin &
steroids is usually effective in myeloma esp
when there is renal insufficiency;
- agents that are nephrotoxic such as plicamycin (
mithramycin) should be avoided;
- parental
pamidronate (biphosphonate) is effective but should be used
w/ caution in renal insufficiency;
-
alkaline phosphatase:
- marker of osteoblast activity;
- is usually not increased in myeloma since there is little new bone formation,
which explains why bone scans appear cold;
- anemia:
- pts w/ diffuse disease & assoc osteopenia have fairly profound
normocytic, normochromic anemia, often w/ Hct of < 30 %;
- platelet deficiency;
-
uric acid: - high level of uric acid (secondary gout);
- renal f(x):
- abnormal renal function;
- lambda light chains, are nephrotoxic, & light-chain myeloma is commonly
complicated by renal failure;
- bence jones proteinuria:
- occurs in less than 50 per cent of patients;
- urinary immunoelectrophoresis may have substantially higher yield
for IgG light chains excreted in the urine.
- dx: monoclonal globulin spike > 1.0 g / 24 hrs for urinary light chains.
