Northann: I would think the main reason to see your primary care physician is to ask for a referral to a neuro doctor. A neurologist at the very least, and preferably, a neurosurgeon who specializes in aneurysms. My understanding is once an aneurysm reaches 5 mm, the neuro docs start the conversation about some kind of intervention, either coiling or a craniotomy, to close the aneurysm off. My aneurysm had grown from 5 to almost 6 before I finally talked myself into taking care of it. Most likely at 4 mm the "watch-and-wait" protocol will be recommended. As an aside, during the 9 months I didn't follow the neurosurgeon's advice to have my aneurysm coiled, I was seeing an osteopath (an actual medical doctor who also does manipulations like a chiropractor) for neck pain. I had never mentioned the neck pain to the neurosurgeon during my initial consult. After my aneurysm was coiled my headaches disappeared. And after the coiling procedure, during my follow up visit, I asked the neurosurgeon where, exactly, the aneurysm was located. From what he explained it was very near from where an artery branched out from my neck. That gave me pause thinking the neck pain and the aneurysm could be related.