A cerebral aneurysm is an abnormal dilatation (widening) of a cerebral artery; it may be fusiform or saccular. It is usually caused by defects in the vessel (artery) wall, which weaken it.
Saccular aneurysms usually appear at the bifurcations of the arteries (where blood pressure collides); they can be single or multiple and appear with a fairly high frequency (2-10% of the population).
Causes of cerebral aneurysm
The causes of cerebral aneurysms are not known, although genetic alterations have been postulated. On the other hand, it is known that certain diseases affecting the formation of collagen, a structural element of the vascular walls, facilitate the appearance of these aneurysms. There are other diseases and conditions that also facilitate the development and rupture of these lesions; the list includes fibromuscular dysplasia, Ehlers Danlos disease (Type IV), Marfan syndrome, Pseudoxanthoma elasticum, Polycystic Liver and Kidney Disease, etc.
It can also appear secondary to hemodynamic stress in association with cerebral arteriovenous vascular malformations, Moya-Moya disease or infections (mycotic aneurysms) or trauma (dissecting aneurysms).
The most important thing is to know what factors can cause these aneurysms to rupture:
- Tobacco
- High blood pressure
- Drug abuse: cocaine, amphetamine, etc..
- Alcohol abuse
Symptoms of a brain aneurysm
On many occasions, cerebral aneurysms are detected when they are asymptomatic. In other cases, they cause symptoms due to mass effect, i.e., compression of neighboring structures, such as pupillary dilation. Other times they cause pain above and behind the eyes or alterations in the visual field.
However, the most frequent form of diagnosis and presentation is after hemorrhage secondary to rupture of these aneurysms, which is one of the major medical emergencies. It is characterized by the sudden onset of a terrible headache (the worst in my life) accompanied by nausea and vomiting. Sometimes it is accompanied by loss of consciousness.
The prognosis of hemorrhage secondary to rupture of an aneurysm (subarachnoid hemorrhage) depends primarily on the patient’s condition after the bleeding. The worse the clinical condition immediately after the hemorrhage, the worse the prognosis.
Diagnosis of a cerebral aneurysm
It is possible to diagnose them by means of a brain CT or brain MRI, although the choice is cerebral arteriography, which is a catheterization of the cerebral vessels.
Treatment of a cerebral aneurysm
The treatment of aneurysms is their exclusion from circulation. This can be achieved by microsurgery and endovascular surgery, to be performed by a specialist in neurosurgery.
Microsurgery has excellent long-term results, although it may have a higher risk in the short term; it is recommended in middle cerebral artery aneurysms. Endovascular surgery has better short-term results, but a higher rate of rebleeding or reopening in the long term; it is recommended in aneurysms of the posterior circulation.
Both systems are safe in the hands of experienced surgeons.
What happens if cerebral aneurysms are left untreated?
There are about 2-10 people per 100 who have a brain aneurysm, yet there are only about 12 hemorrhages per 100,000 population per year, so it is very important to know which aneurysms to treat and which not to treat. And it is not easy.
It is accepted that all aneurysms that have bled should be treated, and that if a person with an aneurysm that has bled has another one (this happens in 20-30% of cases), it should also be treated.
All aneurysms in which growth is demonstrated, and those that are irregular, should also be treated.
All factors that may increase the possibility of rupture of the aneurysm and that we have said above should be absolutely avoided.