Multiple myeloma--presenting as acute kidney injury.

BACKGROUND: Multiple myeloma (MM) is a commonly encountered hematological malignancy with significant renal involvement and often presents as renal failure. The aim of the present study is to analyze clinical spectrum of acute renal failure (ARF) in patients with MM.

MATERIAL AND METHODS: We analyzed 26 (males 24; females 2) patients of multiple myeloma who were referred for evaluation of ARF between July 1994 - June 2007. The referral diagnosis did not include MM in majority 23 (88%) of the patients. Multiple myeloma was diagnosed by at least two of the four features; (1) lytic bone lesions, (2) serum or urine monoclonal peak, (3) Bence Jones proteinuria and (4) more than 20% plama cells in marrow aspirate.

RESULTS: Multiple myeloma contributes 1.93% of total ARF cases (26/1342) over a period of thirteen years. Mean age of patients was 59.3 +/- 7.4 years. The clinical manifestations of myeloma included; anemia (100%), Bence Jones proteinuria (80%), "M" peak in serum electrophoresis (69%), lytic bone lesions (62%), "M" peak in urine electrophoresis (54%), body pain (58%), plasma cells more than 20% in bone marrow aspirate (38%). Oliguric ARF was seen in 73% patients. The precipitating factors of ARF identified were; hypercalcemia (31%); infection (23%); volume depletion (19%); and NSAIDs in (15%). Dialysis support was needed in 77% of the patients because of severe renal failure at presentation with mean serum creatinine of 9.05 +/- 2.84 mg%. Seventeen patients completed chemotherapy, seven last to follow up and two patients died. Ten (38.5%) patients had complete recovery of renal function; three patients had partial recovery and off dialysis and four patients remained dialysis dependent. Remission of myeloma was achieved in nine of seventeen patients treated with chemotherapy Renal biopsy finding in nine patients revealed-cast nephropathy in (4), amyloidosis in (3), proliferative glomerulonephritis in (1) and cast nephropathy with chronic interstitial nephritis and plasma cell infiltration in one patient.

CONCLUSION: Acute reversible renal failure is a common complication in MM, multiple myeloma should be considered as cause a cause of unexplained ARF in middle aged and elderly patients.