Usefulness of Osmolar Excretion Rate in the Diagnosis of Fluids and Electrolytes Overlap Syndromes

Abstract

Clinical practice related to electrolytes and acid-base disorders is commonly approached as a single entity. Overlap syndromes are an uncommon clinical condition that must be considered as part of differential diagnosis when a patient is assessed. The coexistence of electrolytic disorders could make it difficult to interpret certain variables due to the influence of such disorders on the same variable, even in the opposite way. In this context, there are some tools that are very useful in order to establish the correct diagnosis. Thus, osmole excretion rate, tonicity balance, and estimation of electrolyte-free water balance should be considered along with other biochemical variables in order to increase the possibility to make a correct interpretation.