1. Definition of spontaneous subarachnoid hemorrhage refers to the non-traumatic rupture of intracranial blood vessels and the direct flow of blood into the subarachnoid space, also known as primary subarachnoid hemorrhage. 2. Causes of spontaneous subarachnoid hemorrhage Many causes can cause spontaneous subarachnoid hemorrhage, the most important and serious of which is the rupture of cerebral aneurysm, accounting for about 85%, other causes include cerebrovascular malformation, hematologic disorders, non-aneurysmal pericentral hemorrhage, etc. 3. Clinical manifestations of spontaneous subarachnoid hemorrhage Most of them have obvious triggers before onset: such as strenuous exercise, overexertion, excitement, defecation, coughing, alcohol consumption, etc.; a few of them may develop in a quiet state. The main symptom is a sudden onset of significant or unusual unbearable severe headache, which can be at any location, unilaterally or bilaterally. It is accompanied by nausea and vomiting, neck pain, blurred vision, and in severe cases, loss of consciousness and unconsciousness. 4. What tests are needed? Once a spontaneous subarachnoid hemorrhage is suspected, a cranial CT must be performed immediately to clarify the diagnosis. In a few cases where CT is not clear, lumbar cerebrospinal fluid examination can be done. Once a subarachnoid hemorrhage is confirmed, a CTA, or cerebral angiogram (DSA), must be performed to identify the presence of a lesion such as an aneurysm. If the first angiogram does not reveal the cause of the hemorrhage, a repeat angiogram is required 2 weeks later to avoid missing the lesion. 5. Treatment measures When aneurysms and other lesions are found on angiography, doctors with knowledge of surgical techniques and neurointerventional techniques should consult with each other and decide together how to treat them as the best plan. Once the decision is made, surgery or intervention should be given as soon as possible to avoid rebleeding. 6. Health tips for subarachnoid hemorrhage During treatment, the following should be noted: (1) Absolute bed rest to keep the patient stable and reduce the risk of intracranial rebleeding. (2) Reduce visits from visitors and keep the room softly lit to reduce stimulation to the patient. (3) Avoid emotional excitement and sudden exertion, and keep bowel movements unobstructed. (4) Encourage the patient to eat small and frequent meals with easily digestible and nutritious food. (5) Closely observe the patient’s consciousness, pupils, body temperature, pulse, respiration, blood pressure and other vital signs. (6) Avoid smoking and alcohol, eat less spicy food, and eat less oil-pickled products.