Endocrine Abstracts

Performing water deprivation test (WDT) and prolonged water deprivation test (PWDT) is some of the roles undertaken by endocrine nurse in specialist endocrine units. These tests need to be done in a safe and control environment.

Objectives: To provide safe information to patients to avoid fluids overload when they arrive for the tests. Can the specialist endocrine nurse make clinical decision to terminate the test base on clinical evidence and at what point the communication with consultant is crucial in order to collect results of clinical relevance?

Methodology: 35 patients who completed WDT and PWDT over the last 5 years were studied.

Results: Three with overt normal (ON), five with normal (N), three with nephrogenic diabetes insipidus (NDI), 14 with cranial diabetes insipidus (CDI), two with primary polydipsia (PP), eight were excluded due to inability to complete their tests or lack of diagnosis and medical information. ON has the highest mean urine/serum osmolarity ratio at begin and termination of tests. Delay DDAVP during WDT is useful in some cases.

ADH measurement at Peak urine osmolarity can be used to distinguish NDI from CDI. Primary Polydipsia urine/serum osmolarity Ratio increase according to the length of fluid fasting.

Conclusions/recommendations: Address fluids overloading with patients who are coming for these tests. The length of fluids fasting before these tests will be based on patient’s symptoms. Endocrine specialist nurse can make clinical decisions if the tests are overtly normal or serum osmolarity goes above 305 mOsm/kg. Additional markers such as ADH and serum sodium can be useful if needed at certain point during the tests.