What is dialysis disequilibrium syndrome?

From the Guidelines

Dialysis disequilibrium syndrome can be prevented by initiating dialysis gradually in high-risk patients and using specific preventive measures such as reducing blood flow rates and shortening initial dialysis sessions. To prevent dialysis disequilibrium syndrome, it is essential to identify high-risk patients, including those with severe uremia, first-time dialysis patients, children, elderly patients, and those with pre-existing neurological conditions. The following preventive measures can be taken:

• Using a smaller surface area dialyzer
• Reducing blood flow rates to 200-250 mL/min
• Shortening initial dialysis sessions to 2 hours
• Using a sodium modeling technique with higher dialysate sodium concentration
• Adding osmotically active substances like mannitol (0.5-1.0 g/kg) or hypertonic glucose to the dialysate
• Considering prophylactic anticonvulsants in very high-risk patients Treatment of established dialysis disequilibrium involves stopping dialysis immediately, administering anticonvulsants for seizures, providing respiratory support if needed, and using mannitol or hypertonic saline to reduce cerebral edema in severe cases 1. The condition is typically self-limiting, with symptoms resolving within 24 hours, though severe cases may take longer to resolve. It is crucial to recognize that solute disequilibrium can occur during dialysis, and using the equilibrated postdialysis BUN (eKt/V) can provide a more accurate description of the delivered dose of dialysis 1. The eKt/V can be calculated using the formula: eKt/V = spKt/V - (0.6)(K/V) + 0.03, which takes into account the rebound in urea concentration at the end of dialysis 1. By understanding the principles of dialysis disequilibrium syndrome and taking preventive measures, healthcare providers can reduce the risk of this condition and improve patient outcomes. In addition, using the standard Kt/V (stdKt/V) can help to normalize and express the dose of dialysis independent of frequency, which is essential for patients undergoing more frequent dialysis sessions 1. Overall, a comprehensive approach to preventing and treating dialysis disequilibrium syndrome is necessary to minimize its impact on patient morbidity, mortality, and quality of life.

From the Research

Definition and Overview

• Dialysis disequilibrium syndrome (DDS) is a rare and serious complication of hemodialysis that can be potentially fatal 2, 3.
• It is characterized by a clinical constellation of neurologic symptoms and signs occurring during or shortly following dialysis, especially when dialysis is first initiated 3.
• The syndrome is associated with mortality but is also preventable, and identification of patients at risk, preventive measures, early recognition, and prompt management of DDS can minimize morbidity and mortality 3.

Pathophysiology

• The pathophysiology of DDS is not fully understood, but it is thought to be caused by cerebral edema induced by one or more of the following mechanisms: "reverse urea effect", "cerebrospinal fluid acidosis", and "idiogenic osmoles" 4.
• Cerebral edema and increased intracranial pressure are the primary contributing factors to this syndrome and are the target of therapy 5.

Clinical Manifestations

• The signs and symptoms of DDS vary widely from mild forms such as nausea, vomiting, restlessness, and headache, to severe manifestations including seizures, obtundation, coma, and even death 2, 4.
• Early recognition and intervention are essential to prevent the potential deadly effects of this disorder and improve outcomes for patients with end-stage renal disease (ESRD) on hemodialysis 6.

Prevention and Management

• Preventive measures in patients with severe uremia are important, and strategies include raising blood osmolality by introducing solutes (osmoles) into the blood, and decreasing the efficiency of the dialysis treatment 4.
• Treatment of DDS once it has developed is rarely successful, and measures to avoid its development are crucial 5.
• Administration of mannitol and 3% hypertonic saline has been shown to be effective in managing DDS in some cases 2.