Encephalopathy is a well recognized, though poorly understood, complication of renal failure. Generally, it responds well to hemodialysis. Paradoxically, dialysis may precipitate an encephalopathy, as in the three cases reported by Peterson and Swanson,1 who ascribed it to reduced serum osmolality caused by rapid removal of extracellular urea with consequent movement of water into the brain, water intoxication, increased intracranial pressure, and brain stem compression.
As distinct from this acute water intoxication, a more prolonged encephalopathy may be associated with long-term maintenance dialysis. Alfrey and associates2 described five patients who had a speech disorder characterized by slow articulation and stuttering progressing to partial aphasia. The electroencephalogram disclosed slow activity with bursts of delta waves and spikes. Two or three months later the dyspraxia of speech was followed by dyspraxia of other movements, myoclonus, impairment of memory, loss of ability to concentrate, personality changes, and psychotic behavior. After a