The role of parathyroid function and parathyroidectomy in the outcome of aluminium-related dialysis encephalopathy.

Aluminium (Al) intoxication in patients with chronic renal failure may lead to osteomalacia, microcytic anaemia, and encephalopathy. It has been suggested that the expression of Al toxicity may be related to the function of the parathyroid glands. The purpose of this study was to determine whether the functional state of the parathyroids influenced the evolution of Al-related encephalopathy in Al-intoxicated haemodialysed patients. The patients were subdivided into two groups according to outcome: group I patients (n = 6) had died with the clinical feature of severe cerebral dysfunction; group II patients (n = 15) had a favourable outcome with partial or complete recovery. The degree of hyperparathyroidism, as evaluated by plasma biochemistry and bone histology, was comparable in both groups. Three patients of group I and five of group II underwent parathyroidectomy. Before the clinical onset of encephalopathy the duration of Al overload in group I was not different from group II, but after its onset patients of group I were intoxicated significantly longer (8 months +/- 6.6) than those of group II (1.5 months +/- 1.9). This study shows that, in uraemic patients with Al-related encephalopathy, parathyroid function and parathyroidectomy do not play an essential role in clinical outcome. The duration of Al intoxication following the first signs of encephalopathy appears to be the major prognostic element.