Pathogenesis of cerebral edema in patients with acute renal and liver failure and the role of the nephrologist in the management.

PURPOSE OF REVIEW: Acute liver failure (ALF) is a severe and complex illness and one of the most daunting conditions managed in the ICU. Because the renal care is intertwined with multiple disciplines, the aim of this review is to examine the multifactorial pathogenesis of cerebral edema in ALF, covering basic established facts as well as recent advances in our understanding of this condition.

RECENT FINDINGS: Acetaminophen remains the most common cause of ALF in the United States and many European countries. The incidence of cerebral edema continues to decline owing to earlier detection and improved management. The pathogenesis of cerebral edema has shifted from a unifactorial hypothesis involving the failed liver to a multifactorial cause. Recent evidence focuses on the role of liver-induced systemic inflammation and its implication in increasing the permeability of the blood-brain barrier. The role of brain aquaporin-4 in mediating water entry into the brain is further clarified. Controversial data regarding the effect of acute kidney injury on the brain emerged. Hyponatremia has been shown to worsen the outcome in acute-on-chronic liver failure patients thus validating findings in animal models. New evidence shed the light on the changes in serum osmolality and potential tissue hypoxia during continuous renal replacement therapy and points to the risks associated with such therapy.

SUMMARY: ALF is a severe systemic illness that is potentially reversible. Understanding the interaction between the multiple failed organs will help the nephrologist provide well tolerated and efficient care.