Central diabetes insipidus
Central diabetes insipidus is inability of the posterior pituitary to produce adequate antidiuretic hormone, causing free water loss, polyuria, and hypernatremia; common causes include pituitary/hypothalamic tumor, surgery, trauma, and infiltrative disease. Diagnosis is confirmed with a water deprivation test followed by a desmopressin challenge, and treatment is desmopressin (DDAVP) 10-40 mcg intranasally or 0.1-0.4 mg orally, dosed once nightly or twice daily and titrated to control polyuria while avoiding dilutional hyponatremia from over-replacement.
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What this article covers
- Overview
Definition: central diabetes insipidus (DI) is inability of the posterior pituitary gland to produce adequate antidiuretic hormone (ADH, vasopressin), preventing renal water reabsorption and causing polyuria and polydipsia.
- Epidemiology
Central DI can occur at any age and is most often acquired, related to a hypothalamic-pituitary tumor, pituitary or skull-base surgery, head trauma, or infiltrative/autoimmune disease.
- Risk factors
Pituitary or hypothalamic tumor, including craniopharyngioma and other suprasellar masses.
- Pathophysiology
The posterior pituitary normally stores and releases ADH synthesized in the hypothalamus; ADH acts on renal collecting duct aquaporin channels to promote water reabsorption.
- Clinical features
Polyuria, polydipsia, and persistent thirst with dilute urine are the hallmark presenting features.
- Differential diagnosis
Nephrogenic DI: polyuria and hypernatremia from renal ADH resistance (lithium, demeclocycline, amphotericin B, genetic causes) rather than ADH deficiency; distinguished by the absence of urine…
- Diagnosis
Central DI is diagnosed by demonstrating an inappropriately dilute urine in the setting of hypernatremia and elevated serum osmolality, then confirming ADH deficiency (rather than ADH resistance)…
- Management
First, correct the free water deficit and address any hemodynamic instability, replacing free water enterally or with hypotonic IV fluids while hormone replacement is arranged, and monitor serum sodium closely during correction.
- Complications
Severe hypernatremia with altered mental status, lethargy, seizures, or coma occurs if free water access is inadequate to compensate for ongoing water loss, most often in patients who cannot express thirst or access water independently.
- Prognosis
Postoperative central DI is often transient, particularly after pituitary surgery, and may resolve over days to weeks as posterior pituitary function recovers, though some patients progress through the triphasic pattern to permanent DI.
- Prevention
Check serum sodium at least daily for the first postoperative week after pituitary or hypothalamic surgery, since the SIADH phase of the triphasic response peaks around postoperative day 7-8, to…
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Related articles
- Syndrome of inappropriate antidiuretic hormone (SIADH)
SIADH is euvolemic hypotonic hyponatremia caused by antidiuretic hormone secretion or action that is inappropriate for the patient's osmotic and volume status. First-line treatment is fluid restriction to about 800-1,000 mL/day, with vasopressin receptor antagonists (vaptans) or hypertonic saline reserved for severe or symptomatic hyponatremia resistant to fluid restriction.
- Nephrogenic diabetes insipidus
Nephrogenic diabetes insipidus is partial or complete resistance of the renal collecting duct to antidiuretic hormone, most often from chronic lithium therapy, hypercalcemia, or hypokalemia in adults, producing dilute polyuria and compensatory polydipsia. Diagnosis rests on hypernatremia with inappropriately dilute urine that fails to concentrate after desmopressin, and management is stopping the offending drug or correcting the electrolyte abnormality when possible plus a low-sodium, low-protein diet with a thiazide diuretic, adding amiloride if polyuria persists or lithium must continue.
- Hypoglycemia in adults
Hypoglycemia is a plasma glucose below 70 mg/dL, most often a complication of insulin or sulfonylurea therapy for diabetes, and in a person without diabetes it requires a Whipple triad-based evaluation for insulinoma or another endogenous cause. An alert patient is treated with 15 to 20 g of fast-acting oral carbohydrate, while a patient unable to swallow safely receives intramuscular glucagon 1 mg or intravenous dextrose 50% 25 g.
- Hypercalcemia
Hypercalcemia is an elevated serum calcium concentration, most often caused by primary hyperparathyroidism in ambulatory patients or malignancy in hospitalized patients. Mild disease requires only treatment of the underlying cause, while severe or symptomatic hypercalcemia is treated with aggressive IV isotonic fluids, followed by an IV bisphosphonate or denosumab for sustained control and subcutaneous calcitonin as a rapid but short-lived bridge.