Not Just Dehydration: A Case of Early Onset Persistent Hypernatremia in a Preterm Baby
https://doi.org/10.15605/jafes.041.S1
- Author:
Sin Yin Gan
1
;
Wan Nurzahiah Wan Zakaria
1
;
Zurina Zainudin
1
;
Yee Lin Lee
1
Author Information
1. Department of Paediatrics, Hospital Sultan Abdul Aziz Shah, Universiti Putra Malaysia
- Publication Type:Journal Article
- MeSH:
Infant, Newborn;
Dehydration;
Hypernatremia
- From:
Journal of the ASEAN Federation of Endocrine Societies
2026;41(S1):148-
- CountryPhilippines
- Language:English
-
Abstract:
Introduction:Hypernatremia in preterm babies is often due to insensible
water loss, inadequate fluid intake or sodium imbalance
due to immature kidneys. Congenital nephrogenic diabetes
insipidus (CNDI) is an uncommon cause of hypernatremia
in neonates and presents shortly after birth. Early
recognition is important to prevent severe dehydration,
electrolytes imbalance and neurological complications.
Case:We report a case of a preterm 32-week female infant, with a
birth weight of 1.14 kg with persistent hypernatremia (146–
156 mmol/L) from day 4 of life. She received total parenteral nutrition since birth and was started on breastmilk
since day 5 of life. The baby was mildly dehydrated with
weight loss and high urea (6.5 mmol/L) at day 7 of life. Total
fluids were increased to 160 mL/kg/day but serum sodium
remained elevated even though the urea had normalized.
The infant was also noted to have high urine output (5–6
mL/kg/hour) since day 3 of life and suboptimal weight gain.
Further evaluation at age 1 month revealed urine
osmolality 71 mOsm/kg, serum osmolality 308 mOsm/kg
and urine sodium <20 mmol/L when serum sodium was 150
mmol/L, suggestive of DI. A trial of desmopressin showed
unchanged serum sodium (Na), suggesting nephrogenic
DI. Administration of intravenous fluids of 1/5NSD10%
resulted in further increase of both sodium (159 mmol/L)
and serum osmolality (326 mOsm/kg) with low urine
osmolality (111 mOsm/kg). Intravenous fluids were
discontinued and she was started on hydrochlorothiazide
(1 mg/kg/dose bd), resulting in gradual normalization of
sodium 138 mmol/L. Post discharge, she had good weight
gain and normal developmental milestones at corrected
age of 1.5-month-old. Due to early onset hypernatremia,
the infant was referred for genetic testing to rule out CNDI.
Conclusion:Early onset persistent hypernatremia and high urine
output despite adequate fluid management should prompt
evaluation of DI. Early diagnosis is crucial to prevent a
chronic state of hypernatremia that can lead to growth and
developmental delay.
- Full text:2026081017432465581EP_P027.pdf
