Central cranial diabetes insipidus: a clear, practical guide
Ever pee a lot and still feel thirsty? That’s the most common early sign of central cranial diabetes insipidus (DI). It happens when the brain doesn’t make enough vasopressin (anti-diuretic hormone), so the kidneys dump water. You can get severe dehydration and high sodium if you ignore it, but with the right tests and treatment most people do well.
What causes it and what to watch for
Causes are usually damage to the pituitary or hypothalamus: head injury, pituitary surgery, tumors, infections, or autoimmune problems. Sometimes it’s called idiopathic when no clear cause shows up. Symptoms are straightforward: passing large volumes of very dilute urine (often >3 liters a day), extreme thirst, waking at night to drink, dry mouth, and weight loss from fluid loss. In severe cases you may feel weak, confused, or have muscle cramps — signs that sodium is rising.
How doctors diagnose it
Your clinician will check urine volume, urine osmolality (how concentrated the urine is), and blood sodium. A key test used to be the water-deprivation test, but many places now measure urine and blood together and then give desmopressin (a synthetic vasopressin). If urine concentrates after desmopressin, that points to central DI. Brain imaging (MRI) is commonly done to look at the pituitary and surrounding areas to find surgery scars, tumors, or inflammation.
Treatment is aimed at replacing the missing hormone and avoiding dangerous shifts in sodium. Desmopressin (DDAVP) is the standard drug; it comes as a nasal spray, oral tablet, or injection. Dosing is individualized — start low and adjust to stop excessive thirst and prevent low sodium. For partial DI or when desmopressin can’t be used, doctors sometimes use a low-salt diet plus a thiazide diuretic and modest fluid restriction to reduce urine output.
Everyday tips: weigh yourself daily when you start treatment (big changes mean fluid problems), carry water until your dose is stable, and keep a simple log of urine volume and thirst. Know when to seek help: severe dizziness, confusion, seizures, or very high fever need urgent care because they can mean dangerous sodium shifts.
Special situations: infections, surgery, and pregnancy can change how much desmopressin you need. If you get sick or are vomiting, call your care team — doses may need adjusting. If imaging shows a tumor or another treatable cause, addressing that problem can improve or cure DI in some cases.
Want a one-line takeaway? Central cranial DI is treatable and manageable once diagnosed. With simple tests, the right medication, and a few daily checks, you can avoid complications and stay well hydrated without constant worry.
