Treatment for Diabetes Insipidus (DI)
The primary treatment for diabetes insipidus depends on the type: central diabetes insipidus is treated with desmopressin (DDAVP), while nephrogenic diabetes insipidus is managed with thiazide diuretics combined with prostaglandin synthesis inhibitors and dietary modifications. 1, 2, 3
Diagnosis and Classification
- Suspect diabetes insipidus in patients with polyuria, polydipsia, and inappropriately dilute urine (osmolality <200 mOsm/kg H₂O) with high-normal or elevated serum sodium 3, 1
- Initial biochemical workup should include serum sodium, serum osmolality, and urine osmolality 3, 1
- Plasma copeptin levels help distinguish between different types of DI:
- Early genetic testing is strongly recommended for suspected nephrogenic DI 3
Treatment for Central Diabetes Insipidus (CDI)
First-Line Treatment
- Desmopressin (DDAVP) is the treatment of choice for central diabetes insipidus 2, 5, 6
- Available in multiple formulations:
Monitoring and Precautions
- Monitor serum sodium within 7 days and approximately 1 month after initiating therapy, then periodically during treatment 2
- Restrict free water intake to prevent hyponatremia, which is the major complication of desmopressin therapy 2, 7
- More frequent monitoring is needed for patients over 65 years and those at increased risk of hyponatremia 2
- Desmopressin may need to be temporarily or permanently discontinued if hyponatremia occurs 2
Treatment for Nephrogenic Diabetes Insipidus (NDI)
Fluid Management
- Free access to fluid is essential to prevent dehydration, hypernatremia, and growth failure 3, 1
- Patients capable of self-regulating should determine their fluid intake based on thirst sensation 1
- When fasting is required (>4h), intravenous 5% dextrose in water at maintenance rate with close monitoring is recommended 1
Dietary Modifications
- Low salt diet (≤6 g/day) and protein restriction (<1 g/kg/day) to reduce renal osmotic load 3, 1
- For infants, normal-for-age milk intake (instead of water) is recommended to ensure adequate caloric intake 3, 1
- Consider tube feeding in infants and children with repeated episodes of vomiting, dehydration, and/or failure to thrive 3, 1
Pharmacological Treatment
- Thiazide diuretics combined with prostaglandin synthesis inhibitors are recommended for symptomatic patients 3, 1
- Thiazides can reduce diuresis by up to 50% in the short term when combined with a low-salt diet 3, 1
- Add amiloride to thiazide in patients who develop hypokalemia 1
- Note that desmopressin is ineffective and not indicated for nephrogenic diabetes insipidus 2, 8
Emergency Management
- Each patient with DI should have an emergency plan, including a letter explaining their diagnosis with advice regarding intravenous fluid management 1, 9
- For intravenous rehydration, use 5% dextrose solution (not as a bolus) 3, 1
- Close monitoring of clinical status, including neurological condition, fluid balance, weight, and electrolytes is essential 3, 1
- Consider placement of a urinary catheter to ensure proper monitoring of diuresis in hospitalized patients 3
Monitoring and Follow-up
- Regular assessment of height and weight, especially in children 1
- Monitor basic plasma biochemistry (Na, K, Cl, HCO₃, creatinine, osmolality) and urine osmolality 1
- Kidney ultrasound should be performed at least once every 2 years to monitor for urinary tract dilatation and/or bladder dysfunction 1, 9
- Evaluate treatment efficacy via urine osmolality, urine output, weight gain, and growth 1
Special Considerations
- Patients with immune checkpoint inhibitor-related hypophysitis causing central DI require endocrinology consultation and hormone replacement 3
- Pregnancy may exacerbate DI symptoms due to increased placental vasopressinase 8
- Long-term psychosocial outcomes should be monitored, as mental health conditions may be more prevalent in patients with NDI 3