Many are unaware as to what a brain (cerebral) aneurysm is and further, many don’t realise that if managed early, multiple lives could be saved through early intervention.
So, what exactly is a brain aneurysm? I often tell patients that a brain aneurysm can be described as a ticking time bomb that lays silently in the brain and could at any point explode due to a myriad of factors or in certain instances, without any apparent reason at all.
WebMD (a common site used by patients to seek medical knowledge) describes an aneurysm as a bulging weak area in the wall of a blood vessel that supplies blood to the brain. Essentially, this means that the blood supply of our brain is made up of a complex network of vessels that are intrinsically connected to ensure that every part of the brain receives sufficient oxygen and nutrients that are vital for it to function. Any disruption to the functioning of this network of vessels can result in either debilitating problems or sometimes even death.
Overseas studies have shown that brain aneurysms can affect between 1% to 6% of the general population. Individuals are generally not born with brain aneurysms but develop them later in life. This ballooning of the blood vessel in the brain commonly happens in adulthood with peak incidences of ruptured aneurysms occurring between the ages 40 to 60 years. Cigarette smoking, cocaine use, hypertension, a family history of aneurysms and various inherited disorders are amongst the common risk factors for this disease.
Patients with unruptured aneurysms usually don’t have any symptoms or in rare cases may present with symptoms such as headaches, visual, memory or speech disturbances, numbness, weakness or seizures. The main complication caused by a brain aneurysm is when the said aneurysm ruptures and causes a bleed in the brain.
The risk of an aneurysm rupture is low. A study known as the International Study of Unruptured Intracranial Aneurysms (ISUIA) showed an overall annual rupture risk of 0.7%, with another similar study conducted in Japan showing an annual rupture risk of 0.9%.
A patient with a ruptured aneurysm will usually present with a sudden onset of severe headaches, persistent vomiting, change in state of consciousness, coma or death. The mortality rate for such patients is about 50%, and a re-rupture can worsen the mortality rate to 80%.
Screening the general public for a brain aneurysm remains a controversial topic. Considering that a brain aneurysm can lead to devastating complications, one would logically deduce that screening may provide a good option to overcome this problem. Most of these aneurysms, however, are asymptomatic (i.e., showing no signs or symptoms), have a low risk of rupture and the intervention to treat such aneurysms do carry some risk.
Therefore, although screening of the general public is not recommended, screening certain high-risk groups such as those with a history of a previous aneurysm bleed, family members with cerebral aneurysms or those with a genetic disorder known as Autosomal Dominant Polycystic Kidney has been shown to be beneficial. The screening process involves a scan known as a Magnetic Resonance Angiography (MRA) and a follow up with a neurosurgeon if an aneurysm is detected.
During my visit to the Department of Neurosurgery, Fujita Health University, Nagoya, I was intrigued to learn about a health check system termed “The Brain Dock” that was used as a screening tool to diagnose asymptomatic strokes and cerebral aneurysms in patients in Japan. This nationwide survey was initiated at multiple health institutions all over Japan since 1995. The detection rate for a cerebral aneurysm at participating hospitals ranged from 1% to 5%. However, it involved a high cost and was only carried out on those perceived as being at risk. Patients with a confirmed aneurysm were then further assessed to decide on suitability for intervention.
The treatment goal for cerebral aneurysms is to obliterate the neck of the aneurysm and hence prevent the aneurysm from causing a bleed in the brain. This can be done by the application of surgical clips or coiling. The overall complication rate is much lower and the outcome much better when performed in a patient with an unruptured aneurysm. Some studies have shown that surgical clipping may result in a superior outcome to the natural history of patients who are expected to have a life expectancy of no less than ten years.
In summary, the most important message that I would like to convey is that it is important for patients to educate themselves about this disease, the risk factors, and the possible treatment options. Patients who have been diagnosed with a brain aneurysm should be careful about their blood pressure control, quit smoking, avoid any form of stimulant drugs such as cocaine and always discuss the use of supplements or medications such as oral contraceptives with their neurosurgeon to avoid worsening of their condition. If at risk, a consultation with a general practitioner will help you decide on the need for screening. Early diagnosis can lead to better outcomes and prognosis