Diabetes insipidus (DI) is characterized by excessive thirst, and excretion of large amounts of severely diluted urine, with a reduction in fluid intake having no effect on increasing urine concentration.
Central DI, which involves a problem with production of ADH (antidiuretic hormone)
Nephrogenic DI, which is insensitivity of kidney/nephron to ADH
Caused by alcohol or certain types of drug abuse
Nocturia (i.e. voiding at night)
Incidence is 3 in 100k per annum
Diabetes mellitus (although DI causes polyuria, they have different mechanisms, and presentations)