van Gisbergen Maartje, de Moor Ronald, Verrijn Stuart Annemarie, van den Berg Gerrit, Sijbesma Bianco, van Hoften Jacorina
Pediatrics, Elisabeth-TweeSteden Ziekenhuis, Tilburg, The Netherlands.
Wilhelmina Children's Hospital University Medical Centre, Utrecht, The Netherlands.
BMJ Case Rep. 2025 Jan 31;18(1):e262474. doi: 10.1136/bcr-2024-262474.
Worldwide newborn screening (NBS) programmes detect one in 2000-4000 newborns with forms of congenital hypothyroidism (CH). However, some newborns such as premature born babies, are at increased risk for a false-negative test result caused by delayed thyroid-stimulating hormone (TSH) elevation through an immature hypothalamic-pituitary axis. We report a case of a premature newborn in which CH remained undetected. At the age of 3 months cardiorespiratory incidents increased, bradycardia, hypothermia and seizures developed. Investigation revealed severe hypotonic hyponatraemia (85 mmol/L), severe CH (TSH 300 mIU/L, free T4 2 pmol/L), renal insufficiency and metabolic acidosis. High urine osmolality, low urine sodium concentration and an extremely activated renin-angiotensin-aldosterone system suggested a low effective circulating volume. This case report describes hypothyroid-induced hyponatraemia in a premature newborn with a false-negative NBS and thus re-emphasises the importance of repeat screening or repeat thyroid function testing for CH in premature newborns.
全球新生儿筛查（NBS）项目在每2000 - 4000名新生儿中可检测出1例患有某种形式先天性甲状腺功能减退症（CH）的患儿。然而，一些新生儿，如早产儿，由于下丘脑 - 垂体轴不成熟导致促甲状腺激素（TSH）升高延迟，出现假阴性检测结果的风险增加。我们报告了1例未检测出CH的早产新生儿病例。3个月大时，心肺事件增加，出现心动过缓、体温过低和惊厥。检查发现严重低渗性低钠血症（85 mmol/L）、严重CH（TSH 300 mIU/L，游离T4 2 pmol/L）、肾功能不全和代谢性酸中毒。高尿渗透压、低尿钠浓度以及极度激活的肾素 - 血管紧张素 - 醛固酮系统提示有效循环血量低。本病例报告描述了1例患有假阴性NBS的早产新生儿甲状腺功能减退所致低钠血症，从而再次强调了对早产新生儿进行CH重复筛查或重复甲状腺功能检测的重要性。
