Subarachnoid Hemorrhage, Spontaneous

The purpose of this registry is to collect detailed information on the characteristics, treatment, and outcomes of patients with a subarachnoid hemorrhage. This information will enable research aimed at improving the safety and effectiveness of current and future treatments. By studying these data, the investigators aim to identify which treatment strategies offer the best results and which factors are most important in the care of patients with a subarachnoid hemorrhage. The knowledge gained from this research will help improve patient care in the future.

The goal of this observational study is to learn about the role of biomarkers in spontaneous subarachnoid hemorrhage (sSAH) as predictors of severity of clinical outcome. The test of biomarkers is based on regular blood and urinary samples. Blood levels of highly specific cardiac troponin (cTNI), natriuretic peptides (NT-ProBNP), S100 beta protein, neuron-specific enolase (NSE), glial fibrillary acidic protein (GFAP), ubiquitin carboxy-terminal hydrolase (UCH-L1), soluble Tumor Necrosis Factor Receptor-2 (sST2), and soluble urokinase plasminogen activator receptor (suPAR), as well as urinary levels of epinephrine and norepinephrine are the biomarkers explored. All adult participants with spontaneous subarachnoid hemorrhage are involved in the study. The main questions aim to answer are: * which of these molecules can be prognostic for patients' outcome * which are the prognostic levels of these biomarkers to predict patients' outcome. Participants will undergo blood and urinary samples during hospitalization at 24 hours, 72 hours and after 7 days.