Management of Central Diabetes Insipidus
Desmopressin is the first-line treatment for central diabetes insipidus, administered via oral, intranasal, or injection routes, with oral formulations preferred for ease of use and potentially better sodium control. 1, 2
Initial Assessment and Diagnosis Confirmation
Before initiating treatment, confirm the diagnosis by measuring:
- Serum sodium (must be normal before starting therapy) 2
- Serum and urine osmolality (urine osmolality <200 mOsm/kg H₂O is pathognomonic when combined with high-normal or elevated serum sodium) 1
- Plasma copeptin levels (<21.4 pmol/L confirms central DI versus nephrogenic DI) 3, 4
- 24-hour urine volume to establish baseline 1
Pharmacological Management
Desmopressin Therapy
Oral formulation is preferred over intranasal due to ease of administration and evidence suggesting lower incidence of hyponatremia (7.6% vs 11.7% with intranasal) 5. The oral orally disintegrating tablet (ODT) formulation is particularly convenient and well-tolerated 6.
Dosing considerations:
- Oral-to-intranasal conversion ratio averages 1:24, but ranges widely (10.7-31.8) across individuals, requiring careful individual titration 7, 6
- Dose titration should occur over ≤5 days at the study site with monitoring of fluid balance after three consecutive doses 6
- Injectable desmopressin is reserved for acute situations or when oral/intranasal routes are not feasible 2
Critical Safety Monitoring
Hyponatremia is the most serious complication and can lead to seizures, coma, respiratory arrest, or death 2, 8. To prevent this:
- Measure serum sodium within 7 days of initiation, at 1 month, and periodically thereafter 2
- More frequent monitoring is required for patients ≥65 years and those at increased risk 2
- Fluid restriction during treatment is mandatory 2, 9
- Temporarily or permanently discontinue desmopressin if hyponatremia develops 2
Contraindications to desmopressin include:
- Excessive fluid intake 2
- Illnesses causing fluid/electrolyte imbalances 2
- Concurrent use of loop diuretics or systemic/inhaled glucocorticoids 2
Fluid Management
Allow ad libitum fluid access to prevent dehydration, hypernatremia, growth failure, and constipation 1, 4. Patients capable of self-regulation should rely on thirst sensation rather than prescribed fluid amounts, but fluid restriction is necessary during active desmopressin therapy to prevent water intoxication 1, 2.
Ongoing Monitoring Protocol
Regular assessment should include:
- Serum electrolytes (sodium, potassium, chloride) 1, 4
- Urine volume and osmolality or plasma osmolality 1, 2
- Body weight (especially in children for growth monitoring) 1, 3
- Urinary tract ultrasound every 2-3 years to detect complications 1, 4
Special Populations
Pediatric patients: Management remains challenging in young children during intercurrent illness regardless of formulation used 7. Oral desmopressin can be used safely in infants and toddlers with appropriate monitoring 7.
Adipsic patients: These patients present particular management challenges and require especially close monitoring 7.
Post-neurosurgical or head trauma patients: Desmopressin is indicated for temporary polyuria and polydipsia following pituitary surgery or head trauma 2.
Common Pitfalls to Avoid
- Do not attempt to use desmopressin for nephrogenic diabetes insipidus - it is ineffective and contraindicated 2
- Do not use fixed fluid prescriptions - allow thirst-driven intake while maintaining appropriate fluid restriction during active treatment 1, 4
- Do not assume standard conversion ratios when switching formulations - individual titration is essential due to wide inter-individual variation 7, 6
- Do not neglect sodium monitoring - hyponatremia can develop insidiously and become life-threatening 2, 8