My mom died from an aneurism at age 61. She survived one at age 54 and they told her she had another one in her brain stem that was inoperable. So she could die tomorrow or live to be 100. She lasted 7 years before it burst.
Years went by and I started having severe headaches. Given the history with my mom, they suggested I get tested. So I went through a number of CT and MRI scans on my brain. They did not see anything down to some resolution (can't recall now how many microns).
They told me they could do one more test to find even smaller ones, if they existed, but there was a 30% chance of having a stroke during the procedure and recommended I not do that. I agreed! They told me that any aneurism smaller than the ones they already tested for would not be catastrophic bursts. But said if I should have my spinal fluid tested for the presence of blood if symptoms of an aneurism occurred.
Fortunately, they haven't. They never found the cause of the headaches, and they went away shortly after that.
Fun note: Nubain is your friend.
I was having a massive headache. My vision went down to about a toilet paper roll look through. I was screaming in pain. Wife took me to the hospital. They gave me a shot of Nubain for the pain. It's the same thing they gave my wife during labor.
About 20 minutes later, the Dr. comes back to check on me and asks if I still have my headache?
I said "Yes, but it's over there." and pointed at the empty bed next to me.



Dr. laughed.
Still hurt like hell, but you don't care if it hurts 'over there' as long as it's not 'in here'.