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Dialysis Disequilibrium Syndrome — ESENeph MCQ

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ModerateHaemodialysisDialysis Disequilibrium SyndromeESENeph

A 60-year-old man with CKD G5D on haemodialysis develops new-onset seizures. His pre-dialysis urea was 65 mmol/L. He had been non-adherent for 2 weeks and was restarted on intensive daily haemodialysis with a standard prescription. What complication has likely occurred?

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Correct answer: A — Dialysis disequilibrium syndrome – caused by rapid urea removal creating an osmotic gradient between plasma and brain

Dialysis disequilibrium syndrome (DDS) occurs when rapid removal of urea during dialysis creates a transient osmotic gradient between plasma (rapidly cleared) and the brain (slower urea clearance through the blood-brain barrier). Water shifts into the brain causing cerebral oedema, manifesting as headache, nausea, confusion, and seizures. Risk factors include very high pre-dialysis urea, first dialysis sessions, and aggressive dialysis prescriptions. Prevention involves shorter, gentler initial sessions with lower blood flow rates.

Reference: KDOQI 2015 – HD Adequacy; Arieff 1994 – Dialysis Disequilibrium