[Kidney damage in multiple myeloma and other monoclonal gammopathies]

Multiple myeloma typically damages the skeleton in the form of osteolytic lesions or diffuse osteoporosis and causes a decrease in blood production. Renal insufficiency is diagnosed immediately at the onset of illness when establishing diagnosis in up to 20% of patients. Where patients suffer from an advanced form of the illness, it occurs in up to 40%. The predominant cause of damage to the kidneys is the monoclonal light chains. Most frequently, nephropathy is caused by the precipitation of light chains with the Tamm-Horsfall protein in the distal part of the loop of Henle and subsequent tubular ruptures and the creation of fibrous changes in the interstitium. Less frequently, there is clinically serious damage to tubular functions without indication of renal insufficiency. In some patients monoclonal immunoglobulin induces changes in the glomeruli. A rare type of damage is deposits of light chains in the form of AL-amyloid and subsequent nephritic syndrome. A very rare form is the deposition of monoclonal immunoglobulin in the form of amorphous matter (light-chain deposition disease) or in the form of crystals within tissue histiocytes (crystal storing histiocytosis). Both of these disorders cause renal insufficiency and less frequently nephritic syndrome such as AL amyloidosis. With timely and intensive treatment of multiple myeloma, which quickly suppresses the creation of light chains, a significant proportion of patients experience reparative changes and improved kidney function. The benefit of plasmapheresis for patients with severe kidney damage has not been confirmed by randomised studies. At the present time the first positive results are becoming available from tests of the use of pre-emptive haemodialysis with special columns that are permeable for light chains. The aim of the text is to provide information on the various forms of nephropathy whose closer analysis can reveal multiple myeloma and contribute to the timely diagnosis of the cause of the nephropathy.