Nephrogenic Diabetes Insipidus in Childhood: Assessment of Volume Status and Appropriate Fluid Replenishment.

ABSTRACT

Patients affected by nephrogenic diabetes insipidus (NDI) can present with hypernatremic dehydration, and first-line rehydration schemes are completely different from those largely applied in usual conditions determining a mild to severe hypovolemic dehydration/shock. In reporting the case of a patient affected by NDI and presenting with severe dehydration triggered by acute pharyngotonsillitis and vomiting, we want to underline the difficulties in managing this condition. Restoring the free-water plasma amount in patients affected by NDI may not be easy, but some key points can help in the first line management of these patients (1) hypernatremic dehydration should always be suspected; (2) even in presence of severe dehydration, skin turgor may be normal and therefore the skinfold recoll should not be considered in the dehydration assessment; (3) decreased thirst is an important red flag for dehydration; (4) if an incontinent patient with NDI appears to be dehydrated, it is important to place the urethral catheter to accurately measure urine output and to be guided in parenteral fluid administration; (5) if the intravenous route is necessary, the more appropriate fluid replenishment is 5% dextrose in water with an infusion rate that should slightly exceed the urine output; (6) the 0.9% NaCl solution (10 mL/kg) should only be used to restore the volemia in a shocked NDI patient; and (7) it could be useful to stop indomethacin administration until complete restoration of hydration status to avoid a possible worsening of a potential prerenal acute renal failure.