NauseaHeadacheDisorientationConfusionCrampsDizzinessSeizuresComa, or death in severe cases
Causes
You would think that with dialysis being around for half a century, we would understand all its adverse effects by now. With dialysis disequilibrium though, that is not the case and the exact mechanism is still a matter of research. We do have some leads, though:
One of the theories that has been proposed is something called reverse osmotic shift, or reverse urea effect. Essentially what that means is that once dialysis is initiated, removal of toxins (blood urea) leads to relative increase in the amount of water concentration in the blood. This water can then move into brain cells leading it to swell, causing something called cerebral edema. This swelling of the brain cells via this mechanism has been thought of as one of the possible reasons for the usual neurological problems associated with dialysis disequilibrium syndrome. Decreased pH of the brain cells. In layman terms, this would mean that the brain cells have a higher level of “acid”. This has been proposed as another possible cause. Idiogenic osmoles produced in the brain (the details of numbers 2 and 3 are beyond the scope of this article).
Risk Factors
Fortunately, dialysis disequilibrium syndrome is a relatively rare entity and its incidence continues to drop. This has been thought to be due to the fact that patients are now initiated on dialysis at a much lower concentration of urea in the blood.
Here are some situations when a patient could be considered high risk for development of dialysis disequilibrium syndrome:
Older patients and kids New starts on dialysisPatients who already have a neurological disorder like seizures or a strokePatients on hemodialysis (the syndrome is not seen in peritoneal dialysis patients)
Prevention
Since dialysis disequilibrium syndrome is thought to be related to rapid removal of toxins (urea) and fluid from the newly dialyzed patient, certain preventive measures might be helpful. Identifying the high-risk patient, as mentioned above, is the first step. Beyond that, there are certain strategies that might help:
Slow initiation of dialysis, preferably limiting the first session to around 2 hours, with slow blood flow rates Repeating the session for first 3-4 days, daily, which not might be the typical frequency in the long run (hence more frequent, but “gentler” sessions) Infusion of something called mannitol
Treatment
Treatment is mostly symptomatic. Nausea and vomiting can be treated medically using medications like ondansetron. If seizures ever happen, the typical recommendation is to stop dialysis and initiate antiseizure medications. The intensity and the aggressiveness of dialysis might need to be reduced for future treatments.
