Other drugs that may cause diabetes insipidus include demeclocycline, amphotericin B, and orlistat. The mechanisms are diverse and not completely understood. V2 receptor antagonists, such as tolvaptan, may cause transient NDI. Finally, acquired NDI may also occur in the setting of normal aging, which causes a decreased density of collecting duct transporters; hypercalcemia and hypokalemia because these states interfere with reabsorption in the thick ascending limb and therefore decrease the medullary solute gradient; release of bilateral ureteral obstructions because of tubular injury; and amyloidosis, if there is extensive tubular deposition.

PRESENTATION AND DIAGNOSIS

The major symptom of both central and nephrogenic DI is polyuria, arbitrarily defined as greater than 3 L/day of urine production in adults and 2 L/day in children. Additional features often include constant thirst (polydipsia) and fatigue. In children with inherited NDI, failure to thrive and mental retardation may occur secondary to repeated episodes of severe dehydration, if diagnosis and treatment have been delayed.