Mammadova Jamala, Kara Cengiz, Çelebi Bitkin Eda, İzci Güllü Elif, Aydın Murat
Altınbaş University Bahçelievler Medical Park Hospital, Clinic of Pediatric Endocrinology, İstanbul, Turkey
İstinye University Faculty of Medicine, Department of Pediatric Endocrinology, İstanbul, Turkey
J Clin Res Pediatr Endocrinol. 2023 May 29;15(2):214-219. doi: 10.4274/jcrpe.galenos.2021.2021.0191. Epub 2021 Oct 14.
Nephrogenic syndrome of inappropriate antidiuresis (NSIAD) is an X-linked disease caused by activating mutations in the arginine vasopressin (AVP) receptor-2 () 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, 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.
抗利尿激素分泌异常综合征（NSIAD）是一种X连锁疾病，由精氨酸加压素（AVP）受体2（）基因的激活突变引起。尽管AVP水平极低，但受影响的患者仍排出浓缩尿，因此会出现血容量正常的低钠血症。由于其发病率低，患者可能会被误诊和错误治疗。我们报告了两名患有NSIAD的相关男婴，最初被误诊为低肾素性低醛固酮血症（HH）。首先，一名2个月大的男婴出现低钠血症、低血浆渗透压、相对较高的尿渗透压以及低血浆肾素 - 醛固酮水平。这些临床和实验室检查结果与无明显原因的抗利尿激素（ADH）分泌异常综合征相符。因此，在初步诊断为HH的情况下开始使用氟氢可的松治疗。在纠正低钠血症的过程中，氟氢可的松治疗导致高血压，随后立即停药。第二名患者为1岁男童，因羊水过少入院，自出生以来因低钠血症已住院4次，并有癫痫诊断。同样，第二名婴儿的临床和实验室检查结果也与无明显原因的ADH分泌异常综合征相符。尽管血浆AVP水平检测不到，但限水使他的血清钠恢复正常。在这两名婴儿中，基因分析均发现了一个已知突变（c.409C>T；p.R137C），从而确诊为NSIAD。总之，对于所有血容量正常的低钠血症且尿渗透压高但原因不明的患者，均应考虑NSIAD。如果不考虑NSIAD，血浆肾素 - 醛固酮谱可能会与HH混淆，尤其是在婴儿中。
