Winearls CG
Nephrology Forum -- Acute myeloma kidney (REVIEW)
Kidney Int
(Oct) 48:1347-1361 1995
This excellent review of myeloma and renal disease includes the
following points: The diagnosis of myeloma requires at least 2 of the
following 4 criteria: 1) bone marrow with >20% plasma cells of
monoclonal origin; 2) serum monoclonal paraprotein; 3) urine
monoclonal paraprotein; 4) lytic bone lesions. Almost one-half of
patients have some degree of renal insufficiency on presentation.
Acute myeloma kidney (light chain-cast nephropathy) is a
clinicopathologic entity characterized by acute renal failure and cast
nephropathy. Precipitating factors include dehydration, infection,
hypercalcemia, and drugs (NSAIDs). Intravenous radiocontrast
administration in the absence of dehydration may not increase the risk
of ARF. Pathogenesis is believed to be proximal tubular injury
(increases load of light chains to distal tubule) and cast
precipitation in distal tubules. IgD and light chain myeloma commonly
cause ARF. Renal biopsy shows casts in distal convoluted tubules and
collecting ducts, surrounded by inflammatory reaction and giant cells.
Biopsy is indicated if other causes of acute renal failure are
considered to be likely, e.g. ATN, light chain deposition disease,
interstitial nephritis.
Chronic renal failure in myeloma patients usually is due to
irreversible cast nephropathy, amyloidosis, plasma cell infiltration,
or light chain deposition disease. The Fanconi syndrome (proximal
tubular damage alone) also can occur. Albuminuria > 1.0 g/d suggests
a glomerular lesion. Acute myeloma kidney is associated with free
light chains in the urine (one exception being IgD myeloma, which may
not be associated with detectable light chains in urine).
Of 42 patients with myeloma and ARF presenting to the Oxford unit
with a mean age of 66 and in whom serum Cr averaged 10 mg/dl; 22/42
required immediate dialysis. About 50% had not previously been
diagnosed with myeloma. Overall, 36 patients eventually required
dialysis. Only 4 recovered enough function to discontinue dialysis
(however, myeloma is still the most common disease in which recovery
of renal function after prolonged dialysis is seen).
Treatment includes: 1) Prevention of further cast precipitation --
hydration, urinary alkali, stopping NSAIDs, treatment of
hypercalcemia; 2) Chemotherapy -- the best regimen being unknown; 3)
Plasmapheresis? -- no good controlled trials. The prognosis depends
on tumor burden, response to chemotherapy, and degree of renal
failure.
(Leehey)
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ARF etiology :
Multiple myeloma