How is diabetes insipidus managed?

Management of Diabetes Insipidus

The management of diabetes insipidus requires a targeted approach based on the specific type, with central diabetes insipidus requiring desmopressin therapy while nephrogenic diabetes insipidus requires free access to fluids, dietary modifications, and thiazide diuretics with prostaglandin synthesis inhibitors. 1, 2

Diagnosis and Classification

• Suspect diabetes insipidus in patients presenting with polyuria, polydipsia, and inappropriately dilute urine (urine osmolality <200 mOsm/kg H₂O) with high-normal or elevated serum sodium 1
• Early genetic testing is strongly recommended for suspected nephrogenic diabetes insipidus (NDI) to confirm diagnosis 1
• Measure serum sodium, serum osmolality, and urine osmolality as initial biochemical work-up 1
• Plasma copeptin levels can help distinguish between different types of diabetes insipidus:
  • Levels >21.4 pmol/l suggest nephrogenic diabetes insipidus 1
  • Levels <21.4 pmol/l should prompt testing for central diabetes insipidus 1, 3
• Response to desmopressin administration is diagnostic for central diabetes insipidus (shows response) versus nephrogenic diabetes insipidus (shows no response) 3, 2

Management of Central Diabetes Insipidus

• Desmopressin (synthetic ADH) is the primary treatment for central diabetes insipidus 2, 4
• Desmopressin nasal spray is indicated as antidiuretic replacement therapy but is ineffective for nephrogenic diabetes insipidus 2
• Alternative routes of administration (injection) should be considered when the nasal route is compromised due to congestion, discharge, or surgical procedures 2
• Regular monitoring of treatment response through urine volume and osmolality 2

Management of Nephrogenic Diabetes Insipidus

Fluid Management

• Free access to fluid is essential in all patients with NDI to prevent dehydration, hypernatraemia, growth failure, and constipation 1
• Allow patients capable of self-regulating to determine their fluid intake based on thirst sensation rather than prescribed amounts 1, 3
• For patients who cannot self-regulate (infants, cognitively impaired), offer water frequently 1
• When fasting is required (>4h), provide intravenous 5% dextrose in water at maintenance rate with close monitoring 1

Dietary Modifications

• Low salt (≤6 g/day) and protein diet (<1 g/kg/day) with dietetic counseling to reduce renal osmotic load and minimize urine volume 1
• For infants with NDI, normal-for-age milk intake (instead of water) is recommended to ensure adequate caloric intake 1
• Consider tube feeding in infants and children with repeated episodes of vomiting, dehydration, and/or failure to thrive 1

Pharmacological Treatment

• For symptomatic infants and children with NDI, start treatment with a thiazide diuretic and prostaglandin synthesis inhibitors 1
• Thiazide diuretics act by inducing mild volume depletion, reducing diuresis by up to 50% in the short term when combined with a low-salt diet 1
• Add amiloride to thiazide in patients who develop hypokalemia 1
• Prostaglandin synthesis inhibitors are contraindicated during pregnancy 1
• Consider discontinuing prostaglandin synthesis inhibitors once patients reach adulthood or when complete continence is achieved 1

Monitoring and Follow-up

• Regular assessment of height and weight, especially in children 1
• Monitor basic plasma (Na, K, Cl, HCO₃, creatinine, osmolality) and urine (osmolality) biochemistry 1
• Perform kidney ultrasound at least once every 2 years to monitor for urinary tract dilatation and/or bladder dysfunction caused by polyuria 1
• Evaluate treatment efficacy via urine osmolality, urine output, weight gain, and growth 1
• Patients with NDI should be followed by a multidisciplinary team including a nephrologist, dietitian, psychologist, social worker, and urologist 1

Emergency Management

• Each patient with NDI should have an emergency plan, including a letter explaining their diagnosis with advice regarding intravenous fluid management 1
• Use water with dextrose or glucose (e.g., 5% dextrose) for intravenous rehydration 1
• Calculate initial rate of fluid administration to avoid a decrease in serum sodium above 8 mmol/l/day 1
• Close observation of clinical status, including neurological condition, fluid balance, body weight, and serum electrolytes 1
• Patients with NDI and hypernatraemic dehydration should be treated in specialized centers with experience of the disease 1

Special Considerations

• Toilet training in children with NDI should proceed as with any other child, though full continence is usually only reached in the second decade of life 1
• Night incontinence is common in children with NDI, with urine continence at night achieved at a median age of 8-11 years 1
• Urological complications occur in approximately 46% of patients with NDI, including nocturnal enuresis and incomplete voiding 1
• Close monitoring is required when patients with NDI undergo anesthesia or surgery 1