Adrenal Insufficiency in Dogs with Normal Serum Na and CL ∗

Abstract

Summary

A group of 5 adrenalectomized dogs of a large series studied, developed typical signs and symptoms of adrenal insufficiency in the absence of noteworthy alterations in the serum Na and CI values. Hypoglycemia was not present in any of the animals but during insufficiency dehydration and hemoconcentration were evident in 3 of them as indicated by marked increases in hemoglobin. In view of the inspissation of the blood in these dogs it seemed probable that sufficient water was not available for elimination of the electrolytes. This is the interpretation originally given by Nicholson and Soffer(4) to account for the death of their salt-injected dogs. However, a comparison of the hemoglobin concentrations of 8 adrenalectomized dogs exhibiting insufficiency with hyponatriemia (avg. 128 mEq/1) with the hemoglobin increases shown by the 5 animals discussed here, reveals that the hemoconcentration as gauged by hemoglobin changes was not more severe in the latter group. It is unfortunate that plasma volume determinations were not made. However, the drastic decline in arterial pressure and evident weakness of the animals indicated that defective functioning of the vasomotor system was probably the immediate cause of the symptoms. The hyperkaliemia of one dog was of sufficient magnitude to induce cardiac symptoms. The retention of a normal serum electrolyte pattern during insufficiency in these few exceptional dogs is reminiscent of the condition normally occurring in adrenal insufficiency in such animals as the opossum, marmot hamster (13) and certain elasmobranchs.