HEMODIALYSIS as a form of treatment for chronic renal failure has become more frequent in recent years.1-3 Although the technique and details of management have been well established, some patients show deterioration in their general condition toward the end of or immediately following dialysis. Symptoms such as headache, nausea and vomiting, episodes of disorientation, or even grand mal seizures may be seen. Such disturbances are more common during the initial dialytic treatment, but occasionally occur in patients who have had many uneventful dialyses previously.
The cause of these abnormalities is not at all clear. Kennedy et al4 have demonstrated deterioration in the electroencephalogram following dialysis and have postulated that the cerebral dysfunction is due to delayed clearance of the urea from the cerebral spinal fluid (CSF). With the rapid lowering of the blood urea, an osmotic gradient between blood and CSF is established favoring the movement of