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Medical condition Subarachnoid hemorrhage Other names Subarachnoid haemorrhage CT scan of the brain showing subarachnoid hemorrhage as a white area in the center (marked by the arrow) and stretching into the sulci to either side Pronunciation / ˌ s ʌ b ə ˈ r æ k n ɔɪ d ˈ h ɛ m ər ɪ dʒ / Specialty Neurosurgery, Neurology Symptoms Severe headache of rapid onset, vomiting, decreased ...
Some forms of stroke can cause additional symptoms. For example, in intracranial hemorrhage, the affected area may compress other structures. Most forms of stroke are not associated with a headache, apart from subarachnoid hemorrhage and cerebral venous thrombosis and occasionally intracerebral hemorrhage. [33]
Subarachnoid haemorrhage occurs when blood leaks out of damaged vessels into the cerebrospinal fluid in the subarachnoid space around the brain. [2] The most common cause of a subarachnoid hemorrhage is an aneurysm rupture due to the weakened blood vessel walls and increased wall stress. [48]
The broad term, "stroke" can be divided into three categories: brain ischemia, subarachnoid hemorrhage and intracerebral hemorrhage. Brain ischemia can be further subdivided, by cause, into thrombotic, embolic, and hypoperfusion. [3] Thrombotic and embolic are generally focal or multifocal in nature while hypoperfusion affects the brain globally.
Within several hours, the red blood cells in the cerebrospinal fluid are destroyed, releasing their oxygen-carrying molecule heme, which is then metabolized by enzymes to bilirubin, a yellow pigment. The most common cause for bleeding into the subarachnoid space is a subarachnoid hemorrhage from a ruptured cerebral aneurysm. [3]
These cells initially invade the subarachnoid space from the circulation in order to phagocytose the hemorrhaged red blood cells. Following apoptosis, it is thought there is a massive degranulation of vasoconstrictors, including endothelins and free radicals, that cause the vasospasm. [16]
Hemorrhagic stroke may occur on the background of alterations to the blood vessels in the brain, such as cerebral arteriolosclerosis, cerebral amyloid angiopathy, cerebral arteriovenous malformation, brain trauma, brain tumors and an intracranial aneurysm, which can cause intraparenchymal or subarachnoid hemorrhage. [1]
Trauma is the most common cause of intracranial hemorrhage. It can cause epidural hemorrhage, subdural hemorrhage, and subarachnoid hemorrhage. Other condition such as hemorrhagic parenchymal contusion and cerebral microhemorrhages can also be caused by trauma. [3]