Correlation between serum aluminum concentration and signs of encephalopathy in a large population of patients dialyzed with aluminum-free fluids.

The role of persistently high serum aluminum levels (sAl) in the pathogenesis of dialysis encephalopathy (DE) was evaluated in two groups selected from 170 patients dialyzed with low Al fluids. Group 1 (G1) consisted of 24 patients showing two or more sAl below 50 micrograms/l and group 2 (G2) consisted of 27 patients with sAl above 100 micrograms/l in at least 2 of 3 determinations. The two groups did not show any significant difference for age, sex, education or duration of the dialysis treatment. All G1 patients were treated by hemodialysis. In G2, 24 patients underwent hemodialysis and 3 were on continuous ambulatory peritoneal dialysis (CAPD). We evaluated body loads of Al in 25 of 27 G2 patients with the desferrioxamine (DFO) infusion test. All 51 patients underwent a neurological examination and a waking EEG. Intelligence was assessed by Raven's Progressive Matrices 47 test in 19 of the G1 patients and in 20 of the G2 patients; short-term memory was measured by digit span and by word span and long-term memory by a short story in 10 G1 patients and 17 G2 patients. We diagnosed DE only in the presence of the typical EEG changes, with or without manifest clinical symptoms. DE was diagnosed in none of the G1 patients and in 8 of the G2 patients (0 vs 29.6%, chi 2 = 6.34; p less than 0.025). Five of the patients with DE showed both clinical and EEG signs, while the remaining three showed only EEG signs.(ABSTRACT TRUNCATED AT 250 WORDS)