Approach Considerations
Infants ingest relatively large amounts of low renal solute load fluids, either as breast milk or formula, and have a relatively high-volume of dilute urine output to maintain sodium/water homeostasis. In DI, increased fluid turnover is managed by increased free water intake and/or decreased urine output.
Treat patients with DI in an inpatient setting because of the risk of severe dehydration. Destructive or compressive intracranial lesions mandate inpatient stay. Demonstration of an intracranial mass necessitates surgical care.
Distinguishing between central and nephrogenic etiologies is essential to treatment. [20] Transfer to an academic center is highly advised for initial diagnosis and treatment, especially because central DI may require involved diagnostic studies and neurosurgical or oncologic treatment. Surgical procedures of any kind require replacement of fluids at a much higher rate than normal maintenance; inattention to this may result in serious consequences.
Subsequent admissions are determined by the need for intravenous rehydration, especially during intercurrent gastrointestinal illnesses.
Pharmacologic Therapy
For central DI, the treatment of choice is desmopressin (a synthetic vasopressin analogue). It is available in parenteral, intranasal, and oral dosage forms. The doses widely vary depending on the preparation used, so take care to correctly calculate the dose. Other useful medications include chlorpropamide and thiazide diuretics, [21] which can result in a 25-75% reduction in urine volume and can be used in combination with each other.
Nephrogenic DI cannot be effectively treated with desmopressin, because the receptor sites are defective and the kidney is prevented from responding. Thiazide diuretics, amiloride, [22, 23] and indomethacin or aspirin are useful when coupled with a low-solute diet. This approach does not normalize urine output and continues to necessitate increased oral fluid intake.
Aqueous vasopressin and desmopressin preparations are available for intravenous use in emergency circumstances. Overtreatment with desmopressin can result in hyponatremia and seizures. Subcutaneous, intranasal, or oral tablet desmopressin therapy is challenging for caregivers to titrate in a dose appropriate for infants. In one study, dilute intranasal desmopressin administered buccally was found to be a safe treatment alternative for NDI in infancy. [24]
Diet and Activity
Provide affected infants with a breast milk diet to decrease solute load. Protein should account for 6% of caloric intake, and sodium should be reduced to 0.7 mEq/kg/day.
Provide young children with 8% of their caloric intake in the form of protein to enable normal growth. Sodium intake must be maintained at 0.7 mEq/kg/day. (See the video below.)
Activities resulting in increased insensible water loss should be moderated in the presence of massive urinary water loss to prevent dehydration. Heat exposure should be minimized, especially when participating in sports. Avoid creating barriers to drinking water.
Consultations and Long-Term Monitoring
Consultation with the following specialists may be appropriate:
-
Nephrologist
-
Endocrinologist - the presence of central DI should prompt an evaluation of anterior pituitary function
-
Diagnostic radiologist
Regular follow-up visits with an endocrinologist (for central DI) or a nephrologist (for nephrogenic DI) are necessary for dosage adjustment. When indomethacin is used in long-term therapy, carefully observe renal function for any signs of toxicity.
-
Carbs for Kids-Count Them In: The Constant Carbohydrates Diet.
-
Diabetes Sick Day Rules.
-
Taking Diabetes Back to School.
