Correspondence (reply): In Reply

We thank Dr. Kingreen for his valuable input. As stated in our article (1), clinically relevant neurotoxic effects such as confusion, memory and speech impairments as well as—at advanced stages—dementia and both focal and generalized seizures were described for dialysis patients in the past with increased levels of aluminum detected in plasma and brain tissue. The reason for this was the aluminum content of the tap water used for dialysis. Transfer of aluminum via dialysate is also influenced by the type of aluminum compounds present and the pH levels (2). In a specific case in the Netherlands, as detailed by Dr. Kingreen, water used for dialysis was heated in a boiler with two aluminum anodes to prevent corrosion, resulting in high concentrations of aluminum in the water. Dialysis encephalopathies and three deaths were observed. After the boiler use was discontinued, the condition of all patients improved significantly (3). From the end of the 1970s, the process of reverse osmosis was increasingly used for water treatment, leading to significantly lower aluminum concentrations in the dialysate (2). Almost no cases of dialysis encephalopathy have occurred since then.

Oral aluminum-containing phosphate binders are among the most potent phosphate binders, have relatively few side effects, and have been used in particular in the past for dialysis patients (4). Aluminum exposure due to their use should be monitored by determining serum aluminum levels, but this appears to play a minor role in encephalopathy for most dialysis patients.

References