Introduction to Brain Aneurysm
An aneurysm is an abnormal dilation of an artery that appears as a sac-like bulge protruding from the vessel on medical imaging.
What is a Brain Aneurysm?
An aneurysm is an abnormal dilation of an artery that appears as a sac-like bulge protruding from the vessel on medical imaging. Blood flow instead of being directed straight through the artery as in healthy examples can be partially diverted into this dilation and can exert pressures on it from the inside which can further deteriorate the artery’s integrity.
If allowed to progress an aneurysm can cause the blood vessel wall to rupture. This can be catastrophic, leading to haemorrhage, loss of oxygen to the tissues supplied to the blood vessel and death. Aneurisms most commonly occur in parts of the vasculature with thin vessel walls or uniquely high pressures such as in arteries in the brain and the thoracic or abdominal aorta, the chief artery leading from the heart.
What causes a Brain Aneurysm?
Why an aneurism is caused in particular arteries is dependent on a number of factors of such as a weakness in the artery wall which is often found at junctions, areas of high blood pressure or abnormal patterns of blood flow.
More general factors as to why an individual may develop an aneurysm are largely similar to most cardiovascular conditions such as coronary heart disease. These include high blood pressure, high caffeine and alcohol intake, smoking, being overweight, a family history and a high salt diet. Additionally many cardiovascular conditions are more common with age and in people of Afro-Caribbean descent. Women are also more likely to develop aneurisms due to hormonal changes post-menopause. Oestrogen levels decrease massively which subsequently decreases blood vessel elasticity.
Medical history such as recreational drug use, autosomal dominant polycystic kidney disease and certain congenital abnormalities such as aortic coarctation can also contribute to the incidence of aneurysms.
What are the symptoms of a Brain Aneurysm?
Symptoms are largely dependent on the location of the aneurysm and the associated structures that may be affected. In cerebral aneurysms they can affect neurological function through your vision, balance, memory and even your speech. They most commonly also cause headaches, pain and weakness on one side of the face. Should a cerebral aneurysm rupture an individual can expect extremely intense pain, further deterioration in the aforementioned symptoms and potentially seizures or total loss of consciousness.
Aortic aneurysms can grow to more than 5cm large and you may even be able to feel a pulse on your abdomen. Depending on its exact location it may present alongside back and abdominal pain. Should an aortic aneurysm rupture you will feel an intense pain in your chest or abdomen alongside dizziness, a faster heartbeat and maybe loss of consciousness. Unfortunately due to the size of the aorta ruptured aneurysms are fatal without medical intervention.
How is a Brain Aneurysm treated?
Treatment is decided on a case-by-case basis depending on the severity and location of the aneurism, age, medical history, family history and any other medical conditions that may have an influence. Sometimes if a clinician decides that any associated risks of treatment outweigh the benefit of intervention, as is sometimes the case in cerebral aneurysms, the aneurysm is left under observation and the patient is prescribed medication to reduce their blood pressure.
Cerebral aneurysms are commonly treated by coiling them, which involves inserting a thin tube into an artery into your leg and guiding it towards the aneurysm, whereupon the aneurysm is sealed by passing tiny metal coils into it. Neurosurgical clipping is an alternative that physically seals the aneurism with a metal clip which the artery will subsequently heal over.
Aortic aneurysms can also treated surgically in a similar manner to endovascular coiling. However, after a tube is guided through an artery in the leg to the site of the aneurysm a graft is then sealed along the inside of the aortic wall, as the use of coils is impossible in these considerably larger aneurysms. Open surgery is also an option whereby the surgeon will use a synthetic graft to replace the abnormal section of the aorta.