Document Type : Case Report
Department of Pediatrics, Shahid Sadoughi University of Medical sciences, Yazd, Iran
Department of Radiology, Shahid Sadoughi University of Medical Science, Yazd, Iran
Background: Diabetes insipidus is a syndrome that begins with polyuria and is often associated with polydipsia. Three significant differential diagnosis are important to consider in evaluating the causes of polyuria, including primary polydipsia, diabetes mellitus, and diabetes insipidus. In diabetes incipidus, ADH hormone is not synthesized and secreted in central DI or the hormone has lost its function in the renal tubules in nephrogenic DI type.
Case Presentation: The present case was about 5.5 year-old-boy with polyurea and polydipsia from the beginning of the infancy. The patient had the serum osmolality of 277 mOsm/kg with the 24 hours urine volume of 4500 cc and urine osmolality of 200 mOsm/kg. The patient underwent water deprivation test for 12 hours. After administration of 20 μg of desmopressin spray, the urine osmolality increased to 720 mOsm/kg. Central diabetes insipidus was diagnosed. There was posterior hypophyseal agenesis in the brain MRI.
Conclusion: The above patient seemed to be one of the rare cases of autosomal recessive central DI that became symptomatic with polyuria and polydipsia from the early days of life. This rare and interesting case had isolated posterior pituitary agenesis. Desmopressin treatment resolved the patient's complaints. The patient was asymptomatic, and had normal growth in one year follow up.