Central Diabetes Insipidus
Chloe de Crecy
Definition
- Lack of antidiuretic hormone results in free water excreted at kidneys
Etiology
- Idiopathic, autoimmune, tumors (primary or secondary), infiltrative (Langerhans cell histiocytosis), congenital, trauma, surgery, severe shock/ischemia
Presentation
- Polyuria, nocturia, polydipsia
- Elevated Na and osmolality, only if impaired thirst. Can be normal due to compensatory thirst
- Decreased bone mineral density (unclear pathophysiology)
Evaluation
- Confirm polyuria w/ low Uosm (DDx: psychogenic polydipsia, central DI, nephrogenic DI)
- Water restriction. If urine concentrates (Uosm>700), it is primary polydipsia not DI.
- Desmopressin trial (after Na >145) to differentiate between nephrogenic vs central. Central DI responds to desmopressin.
- MRI to investigate cause
Management
- Desmopressin (ADH analog) - PO, IV forms. Given at bedtime.
- Goal: reduce nocturia to improve sleep
- Risk: hyponatremia