The clinical implication of sodium-potassium ratios in dogs

ABSTRACT

Although there have been substantial evidences on the usefulness of electrolytes for the diagnosis of disease, the evidences for a direct link between serum sodium and serum potassium in relation to a specific disease are very limited. This study was performed to investigate an association between diseases and NaK ratios in dogs. From January 1997 to December 1999, a total of 39 cases with an NaK ratio less than 27 were retrieved from the medical records of Veterinary Medical Teaching Hospital, Seoul National University. Ten dogs (25.6%) had a renal or urinary disease, and six (15.4%) had a parasitism. Other miscellaneous diseases included deep pyoderma, grade III patellar luxation, bacterial pneumonia, diabetes, pancreatitis, and pyometra. The NaK ratio was significantly lower in dogs with renal failures than those with parasitic diseases (p=0.0735). With the criterion of the NaK ratio < 27, twenty seven dogs (69.2%) had hyperkalemia, whereas thirteen dogs (33.3%) had hyponatremia. Of 13 dogs with NaK ratios between 20 and 24, six were diagnosed as a renal or urinary tract disease, two as diabetes, and two as a parasitism. The NaK ratios of 9 dogs were < 20, being with the most prevalent with the disease of renal failures (55.6%). The serum NaK ratios were more closely related to serum potassium concentrations (gamma= -0.8710) than serum sodium concentrations (gamma=0.4703). Two dogs with diabetes had an electrolyte pattern of hyperkalemia with normonatremia. Further studies are needed to determine the usefulness of NaK ratio for diagnosis of hypoadrenocorticism, and to establish a relationship between patellar luxation and electrolyte unbalance.