Before rupturing, an aneurysm usually causes no symptoms. However, it can cause symptoms if it does one of the following:
Presses on a nerve (often one that controls eye movement, causing double vision)
Leaks small amounts of blood, causing a headache, typically one that differs from past headaches
The symptoms of subarachnoid hemorrhage can occur minutes to weeks before the rupture. People should report any unusual headaches to a doctor immediately.
When a large aneurysm ruptures, it causes the following symptoms:
Headache, which may be unusually sudden and severe (sometimes called a thunderclap headache)
Facial or eye pain
Double vision
Blurred vision
A stiff neck (usually not immediately)
Loss of consciousness
The sudden, severe headache caused by a rupture peaks within seconds. It is often described as the worst headache ever experienced. The headache is often followed by a brief loss of consciousness. Some people die before reaching a hospital. Some people remain unconscious in a coma and ultimately die. Others wake up, feeling confused and sleepy. They may also feel restless. Within hours or even minutes, people may again become sleepy and confused. They may become unresponsive and difficult to arouse. People may have seizures.
Within 24 hours, blood and cerebrospinal fluid around the brain irritate the layers of tissue covering the brain (meninges), causing a stiff neck as well as continuing headaches, often with vomiting, dizziness, and low back pain.
Frequent fluctuations in the heart rate and in the breathing rate often occur, sometimes accompanied by seizures.
Severe impairments may develop and become permanent within minutes or hours. Fever, continued headaches, and confusion are common during the first 5 to 10 days.
A subarachnoid hemorrhage can lead to other serious problems (complications) such as the following:
Hydrocephalus: Within 24 hours, the blood from a subarachnoid hemorrhage may clot. The clotted blood may prevent the fluid surrounding the brain (cerebrospinal fluid) from draining as it normally does. As a result, blood accumulates within the brain, increasing pressure within the skull. Hydrocephalus may contribute to symptoms such as headaches, sleepiness, confusion, nausea, and vomiting and may increase the risk of coma and death.
Vasospasm: Vasospasm is contraction (spasm) of blood vessels. It occurs in about 25% of people, usually about 3 to 10 days after the hemorrhage. Vasospasm limits blood flow to the brain. Then, brain tissues may not get enough oxygen and may die, as in ischemic stroke. Vasospasm may cause symptoms similar to those of ischemic stroke, such as weakness or loss of sensation on one side of the body, difficulty using or understanding language, dizziness, and impaired coordination.
A second rupture: Sometimes the aneurysm ruptures a second time, usually within a week and with catastrophic results.
