MTP04 - A Structured Diagnostic Approach to the Patient with Hypotonic Polyuria

Learning Objectives:

• Differentiate among the main causes of hypotonic polyuria—arginine vasopressin deficiency (AVP-D, formerly central diabetes insipidus), arginine vasopressin resistance (AVP-R, formerly nephrogenic diabetes insipidus), and primary polydipsia (PP)—and explain the updated pathophysiology and nomenclature framework proposed in recent consensus statements.
• Apply a structured, stepwise diagnostic algorithm that integrates basal laboratory parameters (plasma sodium, osmolality, and copeptin) with dynamic testing, as indicated, to efficiently and accurately classify patients with hypotonic polyuria.
• Incorporate and interpret the newly validated clinical diagnostic score that combines basal sodium, osmolality, copeptin, and clinical variables to correctly identify AVP-D or PP, thereby reducing the need for stimulation testing.