What clinical and laboratory clues suggest myeloma as the cause of AKI?
The signs/symptoms of AKI due to myeloma are similar to typical AKI with a few additions. They may have malignant bone pain, which is often low back pain resistant to rest or simple analgesics. Myeloma should be suspected when the patient has any severe cytopenia (anemia, thrombocytopenia, or pancytopenia resulting from marrow invasion by plasma cells), relatively preserved albumin-corrected calcium (from bone release of calcium), immunoparesis (when all Ig classes are reduced), or an increased globulin fraction. Urinalysis, although important, may be misleading, because the increased urinary excretion of LCs associated with myeloma is not detected by testing for albumin (e.g., Albustix) but only for total protein (e.g., sulfosalicylic acid test) or by specific urine electrophoresis and immunofixation. The diagnosis of myeloma in AKI is now rapidly and preferentially made by the measurement of the serum free light chain (sFLC) ratio
