Nephrogenic Syndrome of Inappropriate Antidiuresis Mimicking Hyporeninemic Hypoaldosteronism: Case Report of Two Infants

Nephrogenic syndrome of inappropriate antidiuresis (NSIAD) is an X-linked disease caused by activating mutations in the arginine vasopressin (AVP) receptor-2 (AVPR2) gene. Affected patients excrete concentrated urine despite very low levels of AVP, and consequently develop euvolemic hyponatremia. Du...

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Main Authors: Jamala Mammadova, Cengiz Kara, Eda Çelebi Bitkin, Elif İzci Güllü, Murat Aydın
Format: Article
Language:English
Published: Galenos Yayincilik 2023-06-01
Series:JCRPE
Subjects:
Online Access:https://jcrpe.org/jvi.aspx?pdir=jcrpe&plng=eng&un=JCRPE-29484&look4=
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author Jamala Mammadova
Cengiz Kara
Eda Çelebi Bitkin
Elif İzci Güllü
Murat Aydın
author_facet Jamala Mammadova
Cengiz Kara
Eda Çelebi Bitkin
Elif İzci Güllü
Murat Aydın
author_sort Jamala Mammadova
collection DOAJ
description Nephrogenic syndrome of inappropriate antidiuresis (NSIAD) is an X-linked disease caused by activating mutations in the arginine vasopressin (AVP) receptor-2 (AVPR2) gene. Affected patients excrete concentrated urine despite very low levels of AVP, and consequently develop euvolemic hyponatremia. Due to its low frequency, patients may be misdiagnosed and treated incorrectly. We report two related male infants with NSIAD that was initially confused with hyporeninemic hypoaldosteronism (HH). First, a 2-month-old male presented with hyponatremia, low plasma osmolality, relatively high urine osmolality, and low plasma renin-aldosterone levels. These clinical and laboratory findings were compatible with syndrome of inappropriate antidiuretic hormone (ADH) secretion without apparent cause. Consequently, fludrocortisone was initiated with a presumptive diagnosis of HH. While correcting hyponatremia, fludrocortisone treatment led to hypertension and was discontinued promptly. The second patient, aged one year, was admitted with a history of oligohydramnios, had been hospitalized four times due to hyponatremia since birth, and had a diagnosis of epilepsy. Similarly, the second infant had clinical and laboratory findings compatible with syndrome of inappropriate ADH secretion with no apparent cause. Fluid restriction normalized his serum sodium despite the plasma AVP level being undetectable. In both infants, AVPR2 gene analysis revealed a known mutation (c.409C>T; p.R137C) and confirmed the diagnosis of NSIAD. In conclusion, NSIAD should be considered in all patients with unexplained euvolemic hyponatremia despite high urine osmolality. If NSAID is not considered, the plasma reninaldosterone profile can be confused with HH, especially in infants.
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spelling doaj.art-b74f29ebb75f4189ad8a7bc39af2aebf2023-06-02T07:47:07ZengGalenos YayincilikJCRPE1308-57271308-57352023-06-0115221421910.4274/jcrpe.galenos.2021.2021.0191Nephrogenic Syndrome of Inappropriate Antidiuresis Mimicking Hyporeninemic Hypoaldosteronism: Case Report of Two InfantsJamala Mammadova0https://orcid.org/0000-0002-8217-1684Cengiz Kara1https://orcid.org/0000-0002-8989-560XEda Çelebi Bitkin2https://orcid.org/0000-0002-6586-7305Elif İzci Güllü3https://orcid.org/0000-0002-5198-8325Murat Aydın4https://orcid.org/0000-0001-7374-229XAltınbaş University Bahçelievler Medical Park Hospital, Clinic of Pediatric Endocrinology, İstanbul, Turkeyİstinye University Faculty of Medicine, Department of Pediatric Endocrinology, İstanbul, TurkeyVan Yüzüncü Yıl University Faculty of Medicine, Department of Pediatric Endocrinology, Van, TurkeyOndokuz Mayıs University Faculty of Medicine, Department of Pediatric Endocrinology, Samsun, TurkeyOndokuz Mayıs University Faculty of Medicine, Department of Pediatric Endocrinology, Samsun, TurkeyNephrogenic syndrome of inappropriate antidiuresis (NSIAD) is an X-linked disease caused by activating mutations in the arginine vasopressin (AVP) receptor-2 (AVPR2) gene. Affected patients excrete concentrated urine despite very low levels of AVP, and consequently develop euvolemic hyponatremia. Due to its low frequency, patients may be misdiagnosed and treated incorrectly. We report two related male infants with NSIAD that was initially confused with hyporeninemic hypoaldosteronism (HH). First, a 2-month-old male presented with hyponatremia, low plasma osmolality, relatively high urine osmolality, and low plasma renin-aldosterone levels. These clinical and laboratory findings were compatible with syndrome of inappropriate antidiuretic hormone (ADH) secretion without apparent cause. Consequently, fludrocortisone was initiated with a presumptive diagnosis of HH. While correcting hyponatremia, fludrocortisone treatment led to hypertension and was discontinued promptly. The second patient, aged one year, was admitted with a history of oligohydramnios, had been hospitalized four times due to hyponatremia since birth, and had a diagnosis of epilepsy. Similarly, the second infant had clinical and laboratory findings compatible with syndrome of inappropriate ADH secretion with no apparent cause. Fluid restriction normalized his serum sodium despite the plasma AVP level being undetectable. In both infants, AVPR2 gene analysis revealed a known mutation (c.409C>T; p.R137C) and confirmed the diagnosis of NSIAD. In conclusion, NSIAD should be considered in all patients with unexplained euvolemic hyponatremia despite high urine osmolality. If NSAID is not considered, the plasma reninaldosterone profile can be confused with HH, especially in infants.https://jcrpe.org/jvi.aspx?pdir=jcrpe&plng=eng&un=JCRPE-29484&look4=avpr2 genehyponatremiainappropriate antidiuretic hormone secretion
spellingShingle Jamala Mammadova
Cengiz Kara
Eda Çelebi Bitkin
Elif İzci Güllü
Murat Aydın
Nephrogenic Syndrome of Inappropriate Antidiuresis Mimicking Hyporeninemic Hypoaldosteronism: Case Report of Two Infants
JCRPE
avpr2 gene
hyponatremia
inappropriate antidiuretic hormone secretion
title Nephrogenic Syndrome of Inappropriate Antidiuresis Mimicking Hyporeninemic Hypoaldosteronism: Case Report of Two Infants
title_full Nephrogenic Syndrome of Inappropriate Antidiuresis Mimicking Hyporeninemic Hypoaldosteronism: Case Report of Two Infants
title_fullStr Nephrogenic Syndrome of Inappropriate Antidiuresis Mimicking Hyporeninemic Hypoaldosteronism: Case Report of Two Infants
title_full_unstemmed Nephrogenic Syndrome of Inappropriate Antidiuresis Mimicking Hyporeninemic Hypoaldosteronism: Case Report of Two Infants
title_short Nephrogenic Syndrome of Inappropriate Antidiuresis Mimicking Hyporeninemic Hypoaldosteronism: Case Report of Two Infants
title_sort nephrogenic syndrome of inappropriate antidiuresis mimicking hyporeninemic hypoaldosteronism case report of two infants
topic avpr2 gene
hyponatremia
inappropriate antidiuretic hormone secretion
url https://jcrpe.org/jvi.aspx?pdir=jcrpe&plng=eng&un=JCRPE-29484&look4=
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AT cengizkara nephrogenicsyndromeofinappropriateantidiuresismimickinghyporeninemichypoaldosteronismcasereportoftwoinfants
AT edacelebibitkin nephrogenicsyndromeofinappropriateantidiuresismimickinghyporeninemichypoaldosteronismcasereportoftwoinfants
AT elifizcigullu nephrogenicsyndromeofinappropriateantidiuresismimickinghyporeninemichypoaldosteronismcasereportoftwoinfants
AT murataydın nephrogenicsyndromeofinappropriateantidiuresismimickinghyporeninemichypoaldosteronismcasereportoftwoinfants