ESPE Abstracts

Background: In pediatric practice, as a rule, differential diagnostics between the three main types of diabetes insipidus DI is to be made: central DI, renal DI and physiological polydipsia of infants – the separation of which is extremely important for the prescription of pathogenetic treatment.

Objective: To make a differential diagnostics of various forms of DI.

Methods: The study involved 14 patients (ten girls and four boys) aged from 1 to 4 years, directed to the Department of Pediatric Endocrinology RSSPCEMHRU diagnosed with DI (central form). They were treated with different doses of desmopressin. To all patients, there were conducted Zimnitsky’s test, blood electrolytes (calcium, phosphorus, sodium, and alkaline phosphatase) and daily urine (calcium and phosphorus), ultrasound of renal, MRT of hypophysis, X-ray of the hand to detect rachitic changes; consulting a nephrologist and genetics.

Results: On the basis of complaints, anamnesis, Zimnitsky’s test (urine specific gravity fluctuations were 1001–1005; daily urine output ranged from 1.7 to 8.5 l); electrolyte composition data of blood and urine, ultra-sound of renal were diagnosed as n=11 (71%); cases of various kinds of tubulopathy made up, n=1 (7.1%) of dismetabolic nephropathy, n=1 (7.1%) of multi enzyme failure and n=1 (7.1%) of physiological polydipsia infants. When prescribing desmopressin an increase of the relative density of urine is not observed. As a result of pathogenetic treatment, there was a significant decrease of polydipsia and polyuria.

Conclusions: The study shows that the use of relative density of urine for the diagnostics of DI in children is entailed with hyper diagnostics of the disease in all patients studied. Taking into account a huge group of genetically determined diseases associated with defects of tubular transport of electrolytes and high frequency in our study (71%), it is necessary to make a deep survey of patients in this age group for the purpose of pathogenetic treatment, prevention of potentially dangerous side effects of improperly prescribed treatment (desmopressin) and for further search of causes of disease.