Subclassification of the Syndrome of Inappropriate ADH Secretion

Subclassification of the Syndrome of Inappropriate Antidiuresis Via Copeptin - What is the Genesis of ADH-independent SIADH?

The aim of this study is to evaluate the different types of osmotic dysregulation in patients with Syndrome of Inappropriate ADH (SIADH) and, hence, to analyze the pathophysiology of SIADH.

These types will be characterized by measurement of AVP and copeptin while performing an osmotic stimulation with infusion of hypertonic saline.

Inclusion Criteria:

• age > 18 years,
• hyponatremia < 132 mmol/L
• SIADH

Exclusion Criteria:

• age < 18 years
• cerebral metastases
• serum sodium > 132mmol/L