When does neurogenic DI usually occur?

It need 90% of vasopressinergic neurons to be destroyed in order to give symptomatic DI For a mass lesion to cause it, it must destroy large area of hypothalamus, or be located at tracks at base of hypothalamus or top of pituitary stalk, or disease of pituitary stalk So usually we have thickening of pituitary stalk with absence of white spot and search for systemic disease associated with it (germinoma, craniopharyngioma, granulatmatos, TB, metastasis...)