Subarachnoid Hemorrhage (SH)
Subarachnoid hemorrhage (SAH) is bleeding into the subarachnoid space — the area between the arachnoid membrane and the pia mater surrounding the brain. Symptoms of SAH include a severe headache with a rapid onset, vomiting, confusion or a lowered level of consciousness, and sometimes seizures. Neck stiffness or neck pain are also relatively common. SAH may occur spontaneously, usually from a ruptured cerebral aneurysm, or may result from head injury. In general, the diagnosis can be determined by a CT scan of the head if done within six hours. Occasionally a lumbar puncture is also required. After confirmation of bleeding further tests are usually performed to find problems that may have caused it, such as an aneurysm.