Treatment should be directed at ameliorating the renal lesion and reduction of the production of paraproteins. In patients with myeloma it is very important to prevent situations that could precipitate acute renal failure. In this respect, dehydration and hypercalcemia are very harmful. Measures should be taken to maintain a high fluid intake. When radiocontrast agents are necessary, hydration before the study decreases the chance of intratubular cast formation between light chains and the contrast agent. Alkalization of the urine can reduce the interaction between light chains and Tamm-Horsfall protein (THP). Nephrotoxic drugs (such as nonsteroidal anti-inflammatory drugs and gentamycin) should not be used because they further enhance tubular dysfunction. Experimental studies suggest that colchicine may be helpful in reducing cast formation either by decreasing THP secretion or modifying the interaction between THP and light chains. Presently, no data exist that document the clinical efficacy of this treatment.
Plasmapheresis has the potential to remove the toxic light chains from the circulation, although in certain patients the serum concentration can be rather low. Plasmapheresis alone does not reduce the rate of production of the paraprotein; therefore, this treatment should be combined with chemotherapy. Patients with extensive cast formation and interstitial changes seem to respond less well to plasmapheresis that do those without cast formation and interstitial changes . Of two controlled studies, only one showed a beneficial effect of addition of plasmapheresis to chemotherapy [82,83]. The major determinant for success seems to be a good response to chemotherapy . Furthermore, patients with extensive cast formation and interstitial changes seem to respond less well to chemotherapy than do those without cast formation and interstitial changes [81,83]. The patient with end-stage renal disease can be treated with dialysis, although survival is poor and dependent on the success of chemotherapy.
The experience of renal transplantation in patients with dyspro-teinemias is, for obvious reasons, rather limited. The results are rather disappointing with a high mortality rate, especially in patients with multiple myeloma and amyloidosis. Patients surviving for more than 1 year show a high recurrence rate [84-87]. Discussion of antitumor therapy is beyond the scope of this review. Briefly, treatment with melphalan and prednisone is considered to be the first choice, whereas more aggressive treatment with vincristine-adriamycin-dexametha-sone is given to patients who do not respond to or who relapse after melphalan and prednisone therapy. Recently, more encouraging results have been obtained with ablative chemotherapy and stem-cell reinfusion . PD—peritoneal dialysis.
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