ESPE Abstracts

This talk will discuss general issues about Copeptin, (e.g. physiology, normal values in children and adults), and the value of Copeptin in vasopressin-dependent fluid disorders, i.e. in patients with diabetes insipidus on the one hand and in patients with the syndrome of inappropriate antidiuresis (SIAD) on the other side. Arginine Vasopressin (AVP) is a peptide composed of 9 amino acids that is synthesized in the hypothalamus. The physiological function of AVP is homeostasis of fluid balance, vascular tonus and regulation of the endocrine stress response. AVP is difficult to measure due to complex pre-analytical requirements and due to technical reasons. Copeptin is the C-terminal part of the vasopressin precursor and has been shown to be a stable, sensitive and simple to measure surrogate marker of AVP release. Therefore, it has emerged as a new diagnostic marker in vasopressin-dependent fluid disorders. The differential diagnosis of diabetes insipidus is challenging. For decades, the water deprivation test was the diagnostic gold standard, but its interpretation is often misleading and the test is cumbersome for patients, adults and children alike. In this presentation, new copeptin-based osmotic and non-osmotic stimulation tests will be discussed. The differential diagnosis of hyponatremia is again challenging. Whether copeptin can be a marker improving differential diagnosis and guide treatment decisions will be debated.