Subarachnoid hemorrhage is a rupture of blood vessels at the base of the brain or cerebrospinal cord due to various causes, and blood flows into the subarachnoid space, also known as primary subarachnoid hemorrhage. Etiology 1, congenital aneurysm, the most common about 50%; 2, cerebrovascular malformation, mostly seen in young people; 3, hypertensive atherosclerotic aneurysm; 4, cerebral base heterogeneous vascular network (Moyamoya disease): common in young people, accounting for 20% of subarachnoid hemorrhage in children; 5, other causes: infectious aneurysm, blood disorders, intracranial venous system thrombosis, etc. Unknown causes account for 10% of cases. Clinical manifestations The main clinical manifestations are sudden severe headache, explosion-like pain, posterior neck and occipital pain, neck stiffness, vomiting, unclear vision, diplopia, photophobia; severe cases are delirious awakening, coma, and even death. It may be accompanied by epilepsy, gastrointestinal bleeding, hemiplegia, psychiatric symptoms, etc. Elderly patients have atypical symptoms, slow onset, insignificant headache, while psychiatric symptoms are obvious, often with incomplete clarity, often accompanied by lung infection, gastrointestinal bleeding, and easily missed. Diagnosis The diagnosis can be confirmed by CT examination and cerebral angiography. Treatment 1.Medical treatment such as absolute bed rest, mannitol dehydration, hemostasis, prevention of cerebral vasospasm and prevention of complications (pulmonary infection, gastrointestinal bleeding, etc.), etc. 2.Surgical treatment If conditions permit, cerebral angiography should be performed first to clarify the cause of bleeding, if it is intracranial aneurysm, aneurysm embolization or craniotomy is feasible to clip the aneurysm or isolated aneurysm; if it is cerebrovascular malformation, embolization or craniotomy can also be performed to remove the malformed vascular mass. For bleeding caused by intracranial venous system thrombosis, local thrombolysis or intravenous thrombolysis is feasible.