L'ipernatremia nel cane e nel gatto: stato dell'arte e presentazione di due casi clinici

Abstract

Hypernatremia in dogs and cats is an alteration of the normal levels of the sodium (>155 mEq/L in the dog and >162 mEq/L in the cat). Causes of hypernatremia are several and they act by different mechanisms. It is classified in: normovolemic, hypovolemic or hypervolemic hypernatremia. The main clinical signs are disorientation, ataxia, convulsions, up to coma and death. These depend on the causes below, severity and the rapidity of the onset of the hypernatremia. There were two clinical cases of hypernatremia caused by primary hypodipsia referred to the Veterinary Teaching Hospital of University of Parma. The animals did not drink water and so they cannot offset the increase of plasmatic osmolarity in relation to hypernatremia. In the dog, primary hypodipsia has been described especially in relation with the abnormalities of corpus callosum in breeds of Miniature Schnauzer and Staffordshire Bull Terrier. Of the two clinical cases reported, only in the dog it has been possible to make a suspected diagnosis of corpus callosum agenesis. Encephalic lesions were not found in the cat. In the feline species, it is the first case in which it has been performed the ADH stimulating test with hypertonic saline. Another important aspect is that the therapy must be assessed correctly to avoid the main risk: the cerebral edema. It is essential to monitor constantly the natremia with serial blood gas analysis at least in the first 48 – 72 hours. At discharge, it was indicated the administration of canned food added with water according to the patient’s requirements and the level of natremia. The plasmatic sodium levels of the two patients improve continuously after a year from the first presentation.