Cebeci Ayse Nurcan, Hebert Steven, Reutter Heiko, Rompel Oliver, Woelfle Joachim
Department of Pediatrics and Adolescent Medicine, University Hospital Erlangen, Friedrich-Alexander University, 91054 Erlangen-Nuremberg, Germany.
Department of Radiology, University Hospital Erlangen, Friedrich-Alexander University, 91054 Erlangen-Nuremberg, Germany.
JCEM Case Rep. 2024 Aug 5;2(8):luae144. doi: 10.1210/jcemcr/luae144. eCollection 2024 Aug.
Achondroplasia is the most common skeletal dysplasia and is associated with serious complications such as foramen magnum stenosis (FMS). This case report describes an infant with achondroplasia who presented with a syndrome of inappropriate antidiuretic hormone secretion (SIADH), secondary to significant FMS and myelocompression. A 2-month-old boy with prenatally diagnosed achondroplasia was referred due to disordered breathing and altered consciousness. On admission, apathy, hypotonus, and hypothermia with typical features of achondroplasia were noticed. Laboratory investigations revealed severe hyponatremia and hypochloridaemia with normal glucose and urea levels. The diagnosis of SIADH was made based on low serum osmolality in the presence of high urine osmolality, along with an elevated copeptin level. An emergency computerized tomography showed a high-grade stenosis at the cranio-cervical junction; subsequent magnetic resonance imaging demonstrated myelocompression. The patient underwent decompression surgery the next day; serum osmolality increased after the operation. Spontaneous breathing after extubation was sufficient whereas tetraplegia persisted despite intensive physiotherapy. Clinicians should be aware of SIADH as a presenting sign of FMS in children with achondroplasia. Further discussion is warranted regarding improving parental education and timing of screening recommendations.
软骨发育不全是最常见的骨骼发育异常，与严重并发症相关，如枕骨大孔狭窄（FMS）。本病例报告描述了一名患有软骨发育不全的婴儿，该婴儿因严重的FMS和脊髓受压继发抗利尿激素分泌不当综合征（SIADH）。一名产前诊断为软骨发育不全的2个月大男孩因呼吸紊乱和意识改变前来就诊。入院时，发现患儿有冷漠、肌张力减退和体温过低等软骨发育不全的典型特征。实验室检查显示严重低钠血症和低氯血症，血糖和尿素水平正常。基于低血清渗透压伴高尿渗透压以及copeptin水平升高，诊断为SIADH。急诊计算机断层扫描显示颅颈交界处高度狭窄；随后的磁共振成像显示脊髓受压。患者于次日接受减压手术；术后血清渗透压升高。拔管后自主呼吸充足，但尽管进行了强化物理治疗，四肢瘫痪仍持续存在。临床医生应意识到SIADH是软骨发育不全儿童FMS的一种表现体征。有必要进一步讨论如何改善家长教育以及筛查建议的时机。
