An aneurysm is a balloon-like bulge that occurs in a weak blood vessel, usually at the point where the vessel branches. An aneurysm that forms in the brain is called a cerebral aneurysm.
These aneurysms are usually only symptomatic if they rupture and usually go undetected otherwise. If an aneurysm does burst, however, the consequences can be life threatening. The rupture of an aneurysm is termed subarachnoid hemorrhage, an event that can lead to severe brain damage, paralysis or death. The outcome for a patient with a ruptured cerebral aneurysm depends on several factors which include:
- Age of the patient
- Extent of the aneurysm
- Location of the aneurysm
- General health of the patient
- Neurological condition after rupture of the aneurysm
While some patients may suffer brain damage, paralysis or death as a result of intracranial bleeding, other individuals recover with little or no neurological effects.
The two main factors that determine patient outcome in cases of subarachnoid hemorrhage are age and the Hunt and Hess grade, a scale that is used to classify the severity of the hemorrhage based on the patient’s clinical condition. The higher the Hunt and Hess grade on admission to hospital, the lower the likelihood of survival.
The Hunt and Hess scale ranges from grade 1 where a patient may be asymptomatic through to grade 5, where a patient may be in a coma or have a rigid posture with their limbs extended, pointed and tense.
For patients that are young and have a Hunt and Hess grade I or II on hospital admission, death or permanent disability are unlikely outcomes. Older individuals with a Hunt and Hess grade of III to V on admission, however, have a poor prognosis. Overall, around two thirds of all patients have a poor outcome after subarachnoid hemorrhage.
Although it can be difficult to detect cerebral aneurysm and anticipate subarachnoid hemorrhage, there are several lifestyle factors that can be modified to reduce the risk of these aneurysms forming. Examples of measure that can be taken to reduce the risk for cerebral aneurysm include quitting smoking and controlling any cases of high blood pressure with the use of suitable medication.
Reviewed by Sally Robertson, BSc