Urinate. Micturate a lot. Urinate often (polyuria). Get up at night to urinate (nocturia). Lots of dilute watery urine. You get thirsty.
That's what you go through when you have diabetes insipidus.
There are two causes:
1. nephrogenic = the kidney does not respond to vasopressin (a.k.a. ADH a.k.a. antidiuretic hormone)
2. neurogenic = there is insufficient production of ADH
Dehydration is the usual complication as this condition can cause the loss of 3 or more litres of fluid per day. Some patients have been known to urinate up to 16 litres per day.
Diabetes insipidus is not to be confused with the more common diabetes mellitus. Diabetes insipidous is not related to a problem with the insulin levels in the body.