Osmotic demyelination syndrome: are patients with end-stage liver disease a special risk group?

The osmotic demyelination syndrome (ODS) is a serious neurological complication associated with the rapid correction of chronic hyponatremia and is associated with high morbidity and mortality. The incidence of ODS after liver transplantation (LT) is 0.8% to 1.4% and is higher than in the general population. Patients with end stage liver disease (ESLD) are very susceptible to ODS primarily because chronic hyponatremia is the most common electrolyte disorder in these patients. Impaired liver function also leads to disruption of astrocyte metabolism resulting in abnormalities of blood-brain barrier function and a decreased ability to generate new intracellular osmotically active compounds (osmolytes) in response to osmotic changes. LT is the only definitive treatment for hyponatremia in ESLD. Massive fluid shifts that occur intraoperatively can change serum sodium concentration (sNa) significantly. The severity of preoperative chronic hyponatremia is an important risk factor for ODS after LT. ODS after LT is most likely due to unintentional sodium administration intraoperatively. Measures to prevent ODS should cover the entire perioperative period. Chronic symptomatic hyponatremia should be carefully treated if LT is imminent. An intraoperative management strategy to minimize increases in sNa is vital and includes limiting fresh frozen plasma and cryoprecipitate administration by using concentrated clotting factors, administering hypotonic intravenous fluids and sodium-free buffering solutions, as well as using low-sodium continuous renal replacement therapy. sNa levels and urine output should be monitored frequently intraoperatively as well as postoperatively. Neurological symptoms are common after LT, and a high index of suspicion must be maintained to diagnose ODS.