{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,3,24]],"date-time":"2026-03-24T08:57:44Z","timestamp":1774342664133,"version":"3.50.1"},"reference-count":38,"publisher":"Frontiers Media SA","license":[{"start":{"date-parts":[[2026,3,24]],"date-time":"2026-03-24T00:00:00Z","timestamp":1774310400000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":["frontiersin.org"],"crossmark-restriction":true},"short-container-title":["Front. Neurol."],"abstract":"<jats:sec>\n                    <jats:title>Background<\/jats:title>\n                    <jats:p>Delayed hydrocephalus, a severe complication following spontaneous subarachnoid hemorrhage (SAH), lacks reliable early biomarkers. Calcium dysregulation has emerged as a potential mediator of secondary brain injury, but the predictive value of serum calcium dynamics for delayed hydrocephalus remains unexplored.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Methods<\/jats:title>\n                    <jats:p>In this observational cohort study, we analyzed serial serum calcium measurements (admission, 72\u202fh, and 7\u202fdays post-ictus) in SAH patients monitored for 90\u202fdays to identify delayed hydrocephalus, defined by radiological ventricular enlargement and clinical neurological deterioration requiring cerebrospinal fluid diversion. Predictive accuracy was evaluated using ROC analysis, and a clinical decision pathway integrating calcium thresholds with neurological assessments was proposed. An admission-variable nomogram was developed using LASSO and logistic regression modeling for early risk stratification. The model was externally validated in a cohort from two hospitals.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Results<\/jats:title>\n                    <jats:p>\n                      Among 302 patients analyzed, delayed hydrocephalus occurred in 24.2%. Serum calcium levels declined over the first week after SAH and were consistently lower at all measured time points among patients who developed delayed hydrocephalus (\n                      <jats:italic>p<\/jats:italic>\n                      &amp;lt;\u202f0.001). Serum calcium at 72\u202fh showed the highest predictive accuracy (AUC\u202f=\u202f0.854), superior to conventional severity scales, with a cutoff \u22647.65\u202fmg\/dL (sensitivity 85.6%, specificity 80.3%). The admission-based nomogram incorporating admission serum calcium, hypertension, Hunt-Hess grade, smoking history, dyslipidemia, alcohol use and diabetes demonstrated excellent performance with an AUC\u202f&amp;gt;\u202f0.93 in internal validation and an AUC of 0.898 in external validation.\n                    <\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Conclusion<\/jats:title>\n                    <jats:p>Dynamic serum calcium levels, particularly hypocalcemia at 72\u202fh, were strongly associated with delayed hydrocephalus after spontaneous SAH and showed good discriminatory performance. An admission-based nomogram provides early individualized risk stratification. These accessible tools could support clinical decision-making, but the proposed calcium cutoff may vary across laboratory assays and therefore warrants multicenter and cross-platform validation (with local calibration where appropriate) and further mechanistic studies.<\/jats:p>\n                  <\/jats:sec>","DOI":"10.3389\/fneur.2026.1762189","type":"journal-article","created":{"date-parts":[[2026,3,24]],"date-time":"2026-03-24T05:25:08Z","timestamp":1774329908000},"update-policy":"https:\/\/doi.org\/10.3389\/crossmark-policy","source":"Crossref","is-referenced-by-count":0,"title":["Serial serum calcium dynamics predict delayed hydrocephalus after spontaneous subarachnoid hemorrhage: development and validation of a clinical nomogram in an observational cohort"],"prefix":"10.3389","volume":"17","author":[{"given":"Di","family":"Wu","sequence":"first","affiliation":[{"name":"Department of Neurosurgery, Tianjin Medical University General Hospital","place":["Tianjin, China"]},{"name":"Department of Neurosurgery, Tianjin Huanhu Hospital","place":["Tianjin, China"]},{"name":"Key Laboratory of Post-trauma Neuro-repair and Regeneration in Central Nervous System, Ministry of Education, Key Laboratory of Injuries, Variations and Regeneration of Nervous System, Tianjin Neurological Institute","place":["Tianjin, China"]}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Xingye","family":"Zhai","sequence":"additional","affiliation":[{"name":"Department of Neurosurgery, Tianjin Medical University General Hospital","place":["Tianjin, China"]},{"name":"Key Laboratory of Post-trauma Neuro-repair and Regeneration in Central Nervous System, Ministry of Education, Key Laboratory of Injuries, Variations and Regeneration of Nervous System, Tianjin Neurological Institute","place":["Tianjin, China"]}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Xinyue","family":"Zhang","sequence":"additional","affiliation":[{"name":"Department of Neurosurgery, Tianjin Medical University General Hospital","place":["Tianjin, China"]},{"name":"Key Laboratory of Post-trauma Neuro-repair and Regeneration in Central Nervous System, Ministry of Education, Key Laboratory of Injuries, Variations and Regeneration of Nervous System, Tianjin Neurological Institute","place":["Tianjin, China"]}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Xu","family":"Han","sequence":"additional","affiliation":[{"name":"Department of Neurosurgery, North China University of Science and Technology Affiliated Hospital","place":["Tangshan, China"]}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Lingyu","family":"Hao","sequence":"additional","affiliation":[{"name":"Department of Neurosurgery, Qinghai University Affiliated Hospital","place":["Xining, Qinghai, China"]}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Cong","family":"Wang","sequence":"additional","affiliation":[{"name":"Department of Neurosurgery, Tianjin Medical University General Hospital","place":["Tianjin, China"]},{"name":"Key Laboratory of Post-trauma Neuro-repair and Regeneration in Central Nervous System, Ministry of Education, Key Laboratory of Injuries, Variations and Regeneration of Nervous System, Tianjin Neurological Institute","place":["Tianjin, China"]}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Sihan","family":"Wang","sequence":"additional","affiliation":[{"name":"Department of Neurosurgery, Tianjin Medical University General Hospital","place":["Tianjin, China"]},{"name":"Key Laboratory of Post-trauma Neuro-repair and Regeneration in Central Nervous System, Ministry of Education, Key Laboratory of Injuries, Variations and Regeneration of Nervous System, Tianjin Neurological Institute","place":["Tianjin, China"]}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Zhen","family":"Wang","sequence":"additional","affiliation":[{"name":"Department of Neurosurgery, Tianjin Medical University General Hospital","place":["Tianjin, China"]},{"name":"Key Laboratory of Post-trauma Neuro-repair and Regeneration in Central Nervous System, Ministry of Education, Key Laboratory of Injuries, Variations and Regeneration of Nervous System, Tianjin Neurological Institute","place":["Tianjin, China"]}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Zengguang","family":"Wang","sequence":"additional","affiliation":[{"name":"Department of Neurosurgery, Tianjin Medical University General Hospital","place":["Tianjin, China"]},{"name":"Key Laboratory of Post-trauma Neuro-repair and Regeneration in Central Nervous System, Ministry of Education, Key Laboratory of Injuries, Variations and Regeneration of Nervous System, Tianjin Neurological Institute","place":["Tianjin, China"]}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Yi","family":"Wang","sequence":"additional","affiliation":[{"name":"Department of Neurosurgery, Tianjin Medical University General Hospital","place":["Tianjin, China"]},{"name":"Key Laboratory of Post-trauma Neuro-repair and Regeneration in Central Nervous System, Ministry of Education, Key Laboratory of Injuries, Variations and Regeneration of Nervous System, Tianjin Neurological Institute","place":["Tianjin, China"]}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"1965","published-online":{"date-parts":[[2026,3,24]]},"reference":[{"key":"ref1","doi-asserted-by":"publisher","first-page":"249","DOI":"10.1093\/brain\/124.2.249","article-title":"Subarachnoid haemorrhage: diagnosis, causes and management","volume":"124","author":"van Gijn","year":"2001","journal-title":"Brain"},{"key":"ref2","volume-title":"Subarachnoid Hemorrhage","author":"Ziu","year":"2025"},{"key":"ref3","doi-asserted-by":"publisher","first-page":"6053","DOI":"10.7150\/thno.100982","article-title":"Subarachnoid hemorrhage distinctively disrupts the glymphatic and meningeal lymphatic systems in 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