Diagnostic Approach to Multiple Myeloma in Elderly Patients with Hypercalcemia and Renal Failure

Clinical Presentation and Diagnostic Criteria

The American Society of Hematology recommends considering multiple myeloma in patients with hypercalcemia, renal failure, anemia, and bone/muscle pain (CRAB criteria), particularly in elderly patients 1, 2
Hypercalcemia (>11.5 mg/dL) causes muscle weakness, fatigue, and contributes to acute renal failure through volume depletion and direct nephrotoxicity 1, 2
Renal failure (creatinine >2 mg/dL) occurs in 20-50% of myeloma patients, typically from light chain cast nephropathy and hypercalcemia 3, 4
Anemia (hemoglobin <10 g/dL or ≥2 g/dL below normal) manifests as fatigue and weakness 1, 2
Bone involvement presents as muscle/bone pain, though lytic lesions may not always be evident initially 1, 2

The International Myeloma Society recommends immediate laboratory tests, including serum and urine protein electrophoresis with immunofixation, 24-hour urine collection for protein electrophoresis, serum free light chain assay with kappa/lambda ratio, and nephelometric quantification of IgG, IgA, and IgM 1
A complete blood count, serum calcium, creatinine, and β2-microglobulin should also be performed 2
Bone marrow examination, including bone marrow aspiration and biopsy with CD138 staining, is necessary to quantify plasma cells (≥10% clonal plasma cells required for diagnosis) 1
Imaging studies, such as a complete skeletal survey and MRI of the spine, are essential for detecting bone marrow involvement and lytic lesions 1, 5

The National Comprehensive Cancer Network recommends immediate hydration (>3 L/24h), hypercalcemia correction, and avoidance of nephrotoxins to protect renal function in patients with multiple myeloma 3, 4
Contrast studies should not be performed without adequate hydration in patients with renal failure 3