Central DI usually starts between the ages of 10 and 20 and occurs in males and females equally. Nephrogenic DI can begin at any age. The term "diabetes" is derived from the Greek word meaning siphon. Signs and symptoms
Excessive urination and extreme thirst and increased fluid intake (especially for cold water and sometimes ice or ice water) are typical for DI. The symptoms of excessive urination and extreme thirst are similar to what is seen in untreated diabetes mellitus, with the distinction that the urine does not contain glucose. Blurred vision is a rarity. Signs of dehydration may also appear in some individuals, since the body cannot conserve much (if any) of the water it takes in.Extreme urination continues throughout the day and the night. In children, DI can interfere with appetite, eating, weight gain and growth, as well. They may present with fever, vomiting or diarrhea. Adults with untreated DI may remain healthy for decades as long as enough water is consumed to offset the urinary losses. However, there is a continuous risk of dehydration and loss of potassium that may lead to hypokalemia. Cause
The several forms of diabetes insipidus are:

Central
Central (or Neurogenic) DI has many possible causes. According to the literature, the principal causes of central DI and their oft-cited approximate frequencies are as follows:

Idiopathic – 30%
Malignant or benign tumors of the brain or pituitary – 25%
Cranial surgery – 20%
Head trauma – 16%

Nephrogenic
Nephrogenic diabetes insipidus is due to the inability of the kidney to respond normally to vasopressin.
This decreases plasma volume, thus lowering the glomerular filtration rate and enhancing the absorption of sodium and water in the proximal nephron. Less fluid reaches the distal nephron, so overall fluid conservation is obtained.Lithium-induced nephrogenic DI may be effectively managed with the administration of amiloride, a potassium-sparing diuretic often used in conjunction with thiazide or loop diuretics. Clinicians have been aware of lithium toxicity for many years, and traditionally have administered thiazide diuretics for lithium-induced polyuria and nephrogenic diabetes insipidus. However, amiloride has recently been shown to be a successful treatment for this condition. Etymology
The word "diabetes" ( or ) comes from Latin diabētēs, which in turn comes from Ancient Greek: διαβήτης, romanized: diabētēs, which literally means "a passer through; a siphon". Ancient Greek physician Aretaeus of Cappadocia (fl. in the first century CE) used that word, with the intended meaning "excessive discharge of urine", as the name for the disease. Ultimately, the word comes from Greek διαβαίνειν (diabainein), meaning "to pass through", which is composed of δια- (dia-), meaning "through" and βαίνειν (bainein), meaning "to go". The word "diabetes" is first recorded in English, in the form "diabete", in a medical text written around 1425. "Insipidus" comes from Latin language insipidus (tasteless), from Latin: in- "not" + sapidus "tasty" from sapere "have a taste"—the full meaning is "lacking flavor or zest; not tasty". Application of this name to DI arose from the fact that diabetes insipidus does not cause glycosuria (excretion of glucose into the urine).