How does multiple myeloma affect kidney function in older adults with reduced GFR?

✓ Accepted answer

Multiple myeloma accelerates kidney damage in older adults by introducing specific toxic mechanisms that compound age-related declines in glomerular filtration rate (GFR). While natural aging typically causes a gradual loss of kidney function, myeloma-induced kidney injury, often called cast nephropathy, can occur rapidly due to the deposition of light chains in the renal tubules.

• Distinguish Myeloma from Aging: Age-related decline is usually slow and stable. Myeloma kidney damage is often acute or subacute, triggered by the accumulation of monoclonal light chains that obstruct tubules. If GFR drops suddenly in a senior patient, myeloma must be ruled out immediately.
• Key Laboratory Markers: Do not rely solely on serum creatinine. Track the 24-hour urine protein electrophoresis to detect Bence Jones protein (light chains), alongside serum free light chain assays. A high kappa-to-lambda ratio is a critical indicator of myeloma-related injury.
• Hematuria and Urine Sediment: Look for "myeloma cast nephropathy" evidence in urine sediment, which includes eosinophilic casts and oval fat bodies. This differs from the bland sediment often seen in chronic age-related kidney disease.
• Medication Adjustments: Many myeloma treatments, such as proteasome inhibitors (e.g., bortezomib) and immunomodulatory drugs, require strict renal dose adjustments. In the US and UK, consult with a hematologist and nephrologist jointly to adjust these dosages based on the patient's specific GFR tier.
• Hydration and Contrast Care: Hydration protocols are vital to flush light chains from the kidneys. Furthermore, when CT scans are required, use non-contrast imaging or ensure adequate pre-hydration, as iodinated contrast agents pose a higher risk of acute kidney injury in this demographic.

admin · 2026-10-11 17:50:00