Renal involvement in multiple myeloma: a 10-year study.

Renal involvement in 204 cases with multiple myeloma admitted over a 10-year period to this tertiary care center in north India was retrospectively examined. Renal involvement occurred in 55 cases (27%); the vast majority of whom (94.5%) had presented with renal failure and 7.3% had nephrotic syndrome. The diagnosis of multiple myeloma was made after admission in 51 of the 55 (92.7%) cases. Oliguria was seen in 23.6% and two-third patients required dialysis. Factors precipitating renal failure were identified in 53% and included dehydration (33%), hypercalcemia (24%), nephrotoxic drugs (16%), sepsis (9%), recent surgery (5%) and contrast media (2%), Severe anemia, hypercalcemia, Bence Jones proteinuria and skeletal abnormalities were more frequent in those with renal involvement. Patients with renal involvement were more likely to have a high tumor burden. The myeloma was of light chain type in 68% of those with renal involvement whereas IgG myeloma was commonest (57%) in those without evidence of renal disease. Renal histology was studied in 27 cases with myeloma cast nephropathy seen in over 60%. Tubulointerstitial nephritis was seen in 14% cases, 11% had amyloidosis, 7% had acute tubular necrosis and 3.6% each had nodular glomerulosclerosis and plasma cell infiltration. In 8 cases (14.6%), renal biopsy provided the first clue to the diagnosis of myeloma. Renal function improved in 33% cases. Only 22% of patients on dialysis survived over 6 months. Median survival in those with renal involvement was only 4 months. Development of unexplained renal failure in an elderly individual with normal sized kidneys, in association with disproportionate anemia even in the absence of skeletal lesions should alert the physician to the diagnosis of multiple myeloma.