The full blown syndrome is rarely seen now. Disequilibrium syndrome most commonly occurs in:
- First few dialysis sessions
- Elderly and pediatric patients
- Patients with pre-existing CNS lesions (recent stroke, head trauma) or conditions characterized by cerebral edema (malignant hypertension, hyponatremia, hepatic encephalopathy)
- High pre-dialysis BUN
- Severe metabolic acidosis
- Cerebral edema resulting from urea removal from the blood more rapidly than from the CSF and brain tissue generating a urea osmotic gradient responsible for water moving into brain cells.
- HD generates a CO2 gradient between plasma and CSF lowering the pH in the CSF and brain tissue. This change will promote an increase in brain cell osmolality due to the rise in H+ concentration and the in-situ generation of osmols (acid radicals from protein metabolism) resulting in brain edema.
- Usually self-limited. However, for severe symptoms HD should be stopped.
- If seizures occur, glucose, diazepam, phenytoin loading followed by infusion
- Osmotically active agents in dialysate have been tried- albumin, glycerol, mannitol3)
- Identify high risk patients
- Reduce dialysis efficacy and limit urea reduction to 30% (smaller dialyzer, decreasing blood flow, sequential dialysis increasing dialysis time), however, a recent small series found tolerance to higher urea reduction4
- Prophylactic administration of osmotically active agents (mannitol, glucose, fructose) and using high sodium dialysate
- IV mannitol 20% at 50 ml/hr with intravenous diazepam- simplest way to prevent DDS in high risk patients5
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- Port FK, Johnson WJ, Klass DW. Prevention of dialysis disequilibrium syndrome by use of high sodium concentration in dialysis. Kidney Int 3:327-333, 1973
- Arieff AI, Massry SG, Barrientos A, Kleman GR. Brain water and electrolyte metabolism in uremia: Effects of slow and rapid HD. Kidney Int 4:177-187, 1973
- Arieff AI. Dialysis disequilibrium syndrome: Current concepts on pathogenesis and prevention [editorial]. Kidney Int 45:629-635, 1994
- Macon EJ. Dialysis disequilibrium after acute dialysis: Must the urea reduction ratio be limited to 30%? J Am Soc Nephrol 9:259A 1998
- Anthony J Nicholls: Nervous System in Daugirdas JT, Blake PG, Todd SI eds : Handbook of Hemodialysis. Third Edition. Philadelphia: Lippincott Williams & Wilikns. 2001:656-666