This interview from Mayo Clinic concerns aneurysms. You can find out exactly what they are - a vulnerable part of a blood vessel where a break can occur. A very severe, lasting headache is often symptomatic of an aneurysm. It's also possible that there is no sign of what is happening. One participant in this session is endovascular surgeon Dr. Rabih Tawk, who has experience dealing with these.
You can get a look at some clinical data showing aneurysms in patients, as well as some treatments for this condition, which depends upon whether the aneurysm has actually burst or not. It has been found that when there is a growth in the size of an aneurysm there is greater likelihood that a surgeon will have to be contacted.
This talk is focused on brain aneurysms, but they can happen anywhere in the body; they occur most frequently in a major artery from the heart, in the brain, in the leg behind the knee, in the intestine or in an artery of the spleen, according to the American Heart Association. There are roughly 200,000 cases in the United States annually.