10 - Effect of Alcohol on Water and Sodium Homeostasis

Abstract

This chapter examines the clinical and laboratory evidence for the effect of alcohol on water and sodium homeostasis. Ethanol ingestion is commonly observed to result in diuresis; the effects on water and sodium excretion are complex. The initial diuresis is followed by a period of water retention and during both phases there is retention of sodium. A normal balance of water can be reached with the prolonged consumption of moderate amounts of ethanol. Despite the fact that the early polyuric state— induced by ethanol ingestion is known for some time, there are conflicting reports regarding its pathogenetic mechanism. Diverse factors are analyzed to improve the understanding of the nature of these responses to ethanol. Thus, the metabolic and endocrine effects of alcohol were reported to act synergistically together with other changes—such as osmolality. The latter could be exacerbated during acute ethanol intoxication, because changes in the osmolar gap caused by ethanol itself or its metabolites could account for an increase in serum osmolality. The kidney is an important target organ that contributes to the expression of ethanol-induced derangements of water and electrolyte homeostasis, but many of the important effect of alcohol on the kidney are indirect.