Hypervitaminosis B12 in maintenance hemodialysis patients receiving massive supplementation of vitamin B12.

We have administered routinely a multivitamin preparation containing a megadose of B12 to 106 hemodialysis patients after dialysis treatments. We found that these patients had very high levels of serum vitamin B12 which returned to original values only after a period of three years after stopping the vitamin. Discontinuing therapy had no effect on hemoglobin, mean erythrocyte corpuscular volume, or motor nerve conduction velocity. It is not known whether maintaining a prolonged high level of vitamin B12 is harmful. However, animal and epidemiologic studies have suggested that both cobalamin and cobalt may be potentially toxic. In view of the absence of demonstrable benefit and the possible risk of toxicity, we believe that the use of such megadose vitamin compounds in dialysis patients should be re-evaluated.

[Role of paired filtration dialysis in substitutive treatment]. / Ruolo della paired filtration dialysis nel trattamento sostitutivo.

The Authors have evaluated the possibilities of use of the PFD in the regular dialysis treatment. At first they have studied in 8 patients the advantages offered by this technique in terms of depuration of small molecules and of tolerance in comparison with HD and HDF. Subsequently, they have compared the performances obtained in HF in a second group of 7 patients with the results observed in PFD executed by using 2 dialyzers on line and, in a second phase, in parallel, extending the comparison parameters to a higher molecular weight solute such as the beta 2-M. The results obtained indicate the PFD as a technique which can offer (compared to HD) a better tolerance and higher depurative performances, which on their turn can eventually allow a reduction of the length of the treatment. Moreover the possibility of executing the PFD with 2 polysulfone dialyzers on line and in parallel, increasing the UF to 13.5 and 15 L, renders this technique competitive with the HF also for its capacity of removing the beta 2-M.

[Evolution of the serum aluminum values in the Piedmont dialysis population. Dialysis Centers of the Piedmont]. / Evoluzione dei valori di alluminio serico nella popolazione dialitica piemontese. Centri Dialisi del Piemonte.

The authors have evaluated the evolution of values of serum aluminium concentration (Als) in the whole pool of patients undergoing RDT in Piedmont in the years 1982-1990. We have compared the data of the Piedmont Regional Registry of Dialysis and Transplantation at the end of 1990 to those obtained in 1982, 1986 and 1989. A progressive reduction has been observed in the percentage of patients with Als > 100 micrograms/l, who were 13.5% of the pool in 1982 and 7.5% in 1986 and finally decreased to 1.5% in 1990. This is yet more evident for patients dialyzing at home as in 1982 43% of them had a Als > 100 micrograms/l, whereas in 1986 only 8.2% did and in 1990 this percentage had decreased to 3.6%. The values of Als (distinguished by type of treatment of chronic renal failure) show end confirm the improvement of the situation of aluminium accumulation, specially as regards bicarbonate HD where the percentage of patients with Als > 100 micrograms/l decreases from 10.5% in 1986 to 1.7% in 1990. These data point out the efficacy of prevention and control programs regarding aluminium pathology performed in the last years in Piedmont. This has led to a reduction of the severe accumulation syndromes observed in the first years of '80 and has allowed the nephrologist to prepare more correct therapeutic prescriptions.

[Scabies in a dalysis unit. Mystery and prejudice]. / La scabbia in un centro dialisi. Mistero e pregiudizio.

BACKGROUND: Pruritus is one of the most common symptoms of uremia. The etiology of uremic pruritus is steel incompletely known. Scabies may be a cause of itching in these patients. METHODS: Retrospective analysis of beginning and developing of a scabies outbreak in a Dialysis Unit with 160 patients. RESULTS: Sixteen cases of scabies were observed in the Dialysis Unit from April 1998 and January 1999: in 6 of them the scarification was positive. In 10 the scarification was negative, but itching disappeared after treatment with benzyl benzoate 20%. Many courses were necessary (max 6). Prophylaxis (treatment with benzyl benzoate 20% for 3 days and lingery cleaning) was applied to approximately 400 people. No cases were observed among health care workers of the Dialysis Unit. CONCLUSIONS: In a Dialysis Unit the diagnosis of scabies is difficult because the patients often have generalized itching; moreover some of them are affected by neuropathy that may make the infestation of scabies more difficult to identify. The most important factor to limitate the outbreak seems to be the prophylaxis of people who take care of patients (health-care workers, family members and car-drivers). It seems also necessary to repeat the treatments many times. The most exposed patients seemed to be those with diminished independence, diabetes and malnutrition.

Three-year follow-up after withdrawal of iron therapy in uremic patients on regular dialytic treatment.

Iron supplementation is commonly recommended in uremic patients undergoing regular dialytic treatment in order to correct a presumed iron deficiency due to impaired absorption and dialytic losses. Serum ferritin levels show an iron overload in 83% of 136 patients on 1.25 g/year i.v. iron therapy. After the withdrawal of iron therapy, directly correlated ferritin levels and percentage transferrin saturation decreased slowly, except in carriers of HLA-A3 antigens and in polytransfused patients. In these latter patients, desferrioxamine reduced but did not normalize the iron balance. The 16 patients who never received iron therapy showed a normal iron balance over a 3-year follow-up. Despite iron-ferritin therapy, 11 patients with baseline ferritin values at the lower normal limits showed a tendency toward further depletion. Orally administered bivalent iron seems to be more promising in normalizing iron-deficient patients without potentially harmful overloading.

Optimizing sodium balance in hemodialysis.

this paper develops and tests a mathematical model for Na+ kinetics applied to standard hemodialysis. The volume of distribution of exchangeable Na+, dialyzer surface area, blood and dialysis fluid flow rate, target weight loss, treatment duration and the Na+ diffusibility constant are taken into account. The model is used to compute the optimal hour by hour dialysis fluid Na+ concentration required to achieve the prescribed end-dialysis natremia and maintain a constant end-dialysis body Na+ pool, while providing a nearly uniform removal of Na+ over dialysis. The model was preliminary tested on 10 consecutive dialyses in a single patient using special dialyzer which generates a part of ultrafiltrate uncontaminated by dialysate.