Monoclonal proteins and renal disease.

Renal insufficiency, which is present initially in almost half of patients with multiple myeloma, usually results from myeloma kidney or hypercalcemia. Neither the class of light chain nor the isoelectric point plays an important role in kidney failure. Acute renal failure must be treated with appropriate fluids and with electrolytes and hemodialysis if necessary. Plasma exchange may be helpful, but has not been proven as such. The presence of a nephrotic syndrome and a monoclonal kappa or lambda light chain in the urine almost always indicates primary amyloidosis (AL) or light-chain deposition disease. Amyloid fibrils must be distinguished from the fibrils of immunotactoid glomerulopathy.