Other contributing factors may include the following: Dependence on others to obtain water Impaired thirst mechanism Impaired renal concentrating capacity (due to diuretics, impaired vasopressin release, or nephron loss accompanying aging or other renal disease) Impaired angiotensin II production (which may contribute directly to the impaired thirst mechanism) Symptoms and Signs of Hypernatremia The major symptom of hypernatremia is thirst.