Severe Unexpected Hyponatremia in an Infant With Cystic Fibrosis Carriership

Simone de Milliano, Nasser E. Ajubi, Farah A. Falix


This report describes the development of severe hyponatremia in a 4-month-old infant, with known carriership of cystic fibrosis (CF; heterozygous delta F508 cystic fibrosis transmembrane conductance regulator (CFTR) mutation), in the course of a coronavirus disease 2019 (COVID-19) infection with mild respiratory symptoms and a urinary tract infection. Laboratory investigations were performed in the outpatient clinic because of persistent loss of appetite, fussiness and mild weight loss after a recent antibiotically treated urinary tract infection. The results showed severe hyponatremia of 115 mmol/L, mild hypokalemia of 3.0 mmol/L, with normal renal function, without other biochemical signs of dehydration and neither signs of fluid retention. Urinary fractional sodium excretion was extremely low, indicative of adequate renal sodium retention in the hyponatremic state. We hypothesize that the combination of disturbed extrarenal salt losses due to CF carriership, together with loss of appetite, relatively low sodium content of breastmilk and possibly COVID-19-associated mild syndrome of inappropriate antidiuretic hormone secretion (SIADH), resulted in the severe hyponatremia that was found in this infant. We believe it is important to report the findings in the current case to underscore the intricate balance of sodium homeostasis in the fully breastfed older infant and the alertness for checking sodium levels during infections/illness in heterozygote CF patients, as was previously reported in literature. In conclusion, this report describes the development of severe unexpected hyponatremia in the course of a mild infectious period in a fully breastfed 4-month-old infant with known CF carriership and underscores the importance of measuring sodium levels with low threshold during infections in CF carriers.

Int J Clin Pediatr. 2023;12(2):45-50


Hyponatremia; Cystic fibrosis carriership; Pediatrics; COVID-19; Breast milk

Full Text: HTML PDF

Browse  Journals  


Journal of Clinical Medicine Research

Journal of Endocrinology and Metabolism

Journal of Clinical Gynecology and Obstetrics

World Journal of Oncology

Gastroenterology Research

Journal of Hematology

Journal of Medical Cases

Journal of Current Surgery

Clinical Infection and Immunity

Cardiology Research

World Journal of Nephrology and Urology

Cellular and Molecular Medicine Research

Journal of Neurology Research

International Journal of Clinical Pediatrics






International Journal of Clinical Pediatrics, quarterly, ISSN 1927-1255 (print), 1927-1263 (online), published by Elmer Press Inc.                     
The content of this site is intended for health care professionals.
This is an open-access journal distributed under the terms of the Creative Commons Attribution-NonCommercial 4.0 International License, which permits unrestricted
non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.
Creative Commons Attribution license (Attribution-NonCommercial 4.0 International
CC-BY-NC 4.0)

This journal follows the International Committee of Medical Journal Editors (ICMJE) recommendations for manuscripts submitted to biomedical journals,
the Committee on Publication Ethics (
COPE) guidelines, and the Principles of Transparency and Best Practice in Scholarly Publishing.

website:   editorial contact:
Address: 9225 Leslie Street, Suite 201, Richmond Hill, Ontario, L4B 3H6, Canada

© Elmer Press Inc. All Rights Reserved.

Disclaimer: The views and opinions expressed in the published articles are those of the authors and do not necessarily reflect the views or opinions of the editors and Elmer Press Inc. This website is provided for medical research and informational purposes only and does not constitute any medical advice or professional services. The information provided in this journal should not be used for diagnosis and treatment, those seeking medical advice should always consult with a licensed physician.