Prognostic Significance of Early ACTH Levels on Neurological Recovery in Patients with Aneurysmal Subarachnoid Hemorrhage: A Prospective Cohort Study

Background/Objectives: Aneurysmal subarachnoid hemorrhage (aSAH) induces a profound stress response and hypothalamic-pituitary-adrenal (HPA) axis dysregulation. Adrenocorticotropic hormone (ACTH), a key component of this axis, may serve as a biomarker reflecting the severity of central nervous system injury. This study aimed to determine the prevalence of acute-phase pituitary dysfunction and investigate the prognostic utility of early ACTH levels for functional outcomes in aSAH patients. Methods: In this prospective cohort study, 20 consecutive aSAH patients admitted within 48 hours of symptom onset were enrolled. Plasma ACTH levels were measured within 7 days of admission, prior to definitive aneurysm treatment. Functional outcomes were assessed at discharge using the Glasgow Outcome Score (GOS) and Modified Rankin Scale (MRS). Statistical analyses employed Spearman correlation and Mann-Whitney U tests. Results: Pituitary dysfunction was identified in 60% of patients (12/20 with ACTH deficiency <7.2 pg/mL). A strong positive correlation was observed between ACTH levels and worse outcomes on the MRS (ρ = +0.67, p = 0.0014), and a significant negative correlation with the GOS (ρ = -0.59, p = 0.0063). Patients with poor outcomes (MRS >2) demonstrated significantly different ACTH distributions compared to those with good outcomes (p = 0.014). Conclusions: Early ACTH measurement demonstrates significant prognostic value in aSAH, supporting its potential as a biomarker for outcome prediction. The high prevalence of acute ACTH deficiency highlights substantial early HPA axis disruption, warranting systematic endocrine evaluation and opening avenues for research into molecular mechanisms and potential therapeutic interventions.