Polyuria (>3 L/24 h)

Primary polydipsia

Psychogenic
Hypothalamic disease
Drugs (thioridazine, chlorpromazine, anticholinergic agents)

Solute diuresis:

Glucose, mannitol, radiocontrast urea (from high protein feeding), medullary cystic diseases, resolving ATN, or obstruction diuretics

End

Urine osmolality

<250 mosmol

>300 mosmol

History, low serum sodium

Water deprivation test or ADH level

Diabetes insipidus (DI)

Central DI (vasopressin-sensitive)

posthypophysectomy, trauma, supra- or intrasellar tumor/cyst, histiocytosis or granuloma, encroachment by aneurysm, Sheehan's syndrome, infection, Guillain-Barré, fat embolus, empty sella

Nephrogenic DI (vasopressin-insensitive):

Acquired tubular diseases: pyelonephritis, analgesic nephropathy, multiple myeloma, amyloidosis, obstruction, sarcoidosis, hypercalcemia or hypokalemia, Sjögren's syndrome, sickle cell anemia

Drugs or toxins: lithium, demeclocycline, methoxyflurane, ethanol, diphenylhydantoin, propoxyphene, amphotericin

Congenital: hereditary, polycystic or medullary cystic disease