Abstract: Idiopathetic central diabetes insipidus (CDI) is a heterogeneous hypothalamus-pituitary disease due to the absence or deficiency of arginine vasopressin (AVP).Overexcretion of dilute urine causes body's hydration state and symptoms of extraordinary thirst,even with copious water intake (up to 20 L per day).The diagnosis of CDI is commonly confirmed with water deprivation test and vasopressin analog response.1 This disorder is usually caused by the destruction or degeneration of AVP-secreting magnocellular neurons in hypothalamic supraoptic and paraventricular nuclei.The classical radiological change of CDI is loss of "bright spot" in MRI image,but it is always not special for differential diagnosis of underlying causes.