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Acta sci. vet. (Impr.); 41(supl.1): Pub. 22, 2013. tab

Artigo em Português | VETINDEX | ID: biblio-1372653

Resumo

Background: Diabetes insipidus (DI) is a rare endocrine disorder in dogs altering the mechanism of retention and excretion of water, with concomitant polyuria and polydipsia (PU/PD), and low urine specific gravity. The water deprivation test followed by response to application of desmopressin is the diagnostic test for the disease. However, the literature is still scarce about laboratorial and clinical aspects of DI in small animals. Thus, the aim of this study is to report a case of DI in a canine, emphasizing its diagnosis through the water deprivation test. Case: A male mongrel dog, 5 years-old, not neutered, 13kg of body weight, was presented with intense PU/PD (500mL/kg/day of water consumption). Physical examination showed normal routine clinical parameters. Additional tests were asked (abdominal ultrasound, blood count, serum biochemical (creatinine, alanine aminotransferase (ALT), total cholesterol, alkaline phosphatase (ALP) and glucose) and dexamethasone suppression test), but they showed no significant changes. Thus, it was suspected that the animal had an uncommon endocrinopathy, DI. For its confirmation, it was made the water deprivation test with application of desmopressin acetate. The patient remained without access to water and without fluidtherapy with urethral sounding and bladder emptying. The measurement of urinary gravity and volume were made every hour for 12 h. After 8 h from the start of the test, it was made the application of desmopressin acetate (three drops in the conjunctival sac), because the animal began to exhibit tremors and muscle weakness (urine specific gravity: 1005). In this period, their body weight decreased 11.6%. After application of desmopressin, urine specific gravity increased gradually every hour, ending with urine specific gravity measurements of 1023, confirming the diagnosis of central DI. Discussion: The diagnosis of DI can be a challenge to the veterinary practitioner since it is a rare disease in small animals, and often is not included in the differential diagnoses. Furthermore, additional tests such as common hematological, biochemical and electrolyte profiles usually have normal results, or secondary influences of dehydration. The water deprivation test confirms the inability of the animal to concentrate urine in DI. However, this test is potentially dangerous because of the serious consequences of dehydration, requiring constant monitoring. In DI of central origin (DIC), the urinary concentration usually starts 1 to 3 h after administration of desmopressin acetate, and tends to be within the normal reference value, as can be observed in this case. Because there were not neurological signs, the final diagnosis of the animal was acquired DIC. DIC is acquired by the destruction of cells of supraoptic and paraventricular nuclei of the hypothalamus, or even, loss of the ducts that carry the anti-diuretic hormone (ADH) by the pituitary for secretion and storage. Desmopressin acetate (dDAVP), a synthetic analogue of vasopressin, was used for the initial treatment (three drops in the conjunctival sac, once a day) which controlled the PU/PD of the animal. After four months of treatment initiation, the animal has moved to a drop of the drug, twice a day. The dog of the present case has reported good prognosis, since small animals with acquired DIC become relatively asymptomatic in response to appropriate therapy.

Biblioteca responsável: BR68.1