Subarachnoid hemorrhage refers to a clinical syndrome caused by the rupture of a diseased blood vessel at the base or surface of the brain and the direct flow of blood into the subarachnoid space, also known as primary subarachnoid hemorrhage, which accounts for about 10% of acute stroke and is a very serious and common disease. The incidence rate in China is about 2.0/100,000 people per year according to the World Health Organization survey, and 6-20/100,000 people per year have also been reported. It can also be seen as secondary subarachnoid hemorrhage due to intracerebral parenchymal, ventricular hemorrhage, rupture of epidural or subdural vessels and blood penetrating brain tissue into the subarachnoid space. Unlike common hypertensive cerebral hemorrhage, SAH is mostly due to intracranial vascular lesions. The most common causes include aneurysms, vascular malformations, arteriovenous fistulas, and other causes. These diseases have a high probability of rebleeding leading to coma and death if not managed quickly surgically. Many patients referred below clinically have lost their lives due to delayed treatment. Then how to determine subarachnoid hemorrhage: 1. Clinical manifestations: 1. Headache and vomiting Sudden severe headache, vomiting, facial pallor, generalized cold sweat. If the headache is limited to a certain place, it has localization significance, such as anterior headache suggesting supratentorial and cerebral hemispheres (unilateral pain), and posterior headache indicating posterior cranial recess lesion. 2. Disorders of consciousness and psychiatric symptoms Most patients do not have disorders of consciousness, but may have irritability. In critical cases, there may be delirium, varying degrees of unconsciousness and coma, and a few may have seizures and psychiatric symptoms. Meningeal irritation signs are common and obvious in young and middle-aged patients, accompanied by neck and back pain. Elderly patients, early hemorrhage or those in deep coma may not have meningeal irritation signs. CT is an effective method for diagnosing subarachnoid hemorrhage. If CT shows pools and high-density hemorrhagic signs in the subarachnoid space and trauma is excluded, spontaneous subarachnoid hemorrhage can be diagnosed. DSA angiography is an important tool to diagnose the cause of subarachnoid hemorrhage, and only when the nature and location of the lesion are clear can effective surgical treatment be performed. What to do if you encounter a patient with subarachnoid hemorrhage: 1. Send the patient to a nearby hospital for emergency treatment as early as possible to ensure stable vital signs. If the cause of the hemorrhage is clear, or if local imaging cannot be completed, the patient should be referred to a higher level neurosurgery hospital for further treatment. 4. During conservative treatment, the patient should be absolutely bed-ridden to maintain calmness, relieve pain, stop bleeding, pass stools, and avoid emotional stress. Our department has rich experience in treating subarachnoid hemorrhage, and we welcome patients to contact us in time. Subarachnoid hemorrhage, a surgical disease should not be delayed.