Could someone please explain how GCA causes blindness.How does
it happen? Thanks to all who explain
This is off this website:
If an affected blood vessel (artery) becomes very swollen (inflamed), the blood supply going down that artery can become blocked. The most common arteries this affects are the small arteries going to the eye. If one of these arteries becomes blocked it can cause permanent, serious visual problems, even total loss of vision, in the affected eye. Total or partial loss of vision may occur in up to 1 in 5 people with untreated giant cell arteritis (GCA). Once vision is lost, there is little chance of recovery of vision, even with treatment. Therefore, treatment is aimed at preventing visual loss or, if visual loss has occurred in one eye, to prevent loss in the other eye. However, even with treatment, visual loss occurs in up to 1 in 20 cases
https://patient.info/health/giant-cell-arteritis-leaflet
Flip's answer is (nearly) perfect! I'd dispute this statement: "The most common arteries this affects are the small arteries going to the eye". That is part of the misapprehension that many doctors labour under that you can't have GCA if you don't have visual symptoms and headache. GCA can affect any artery that has an elastic component to its wall. It also affects arteries in the chest, including the aorta, the artery that takes blood away from the heart to supply the rest of the body. GCA is classed as a Large Vessel Arteritis - arteries in the head are pretty small! GCA affecting these larger arteries cause the PMR-type symptoms as well as claudication.
The name gives it away, Giant Cell Arteritis. In the particular form of inflammation that is found in GCA (there are other forms and they can also do something similar), giant cells form in the walls of the arteries. If there are too many or they get too large the diameter of the blood vessel is reduced and can even be squashed completely so that the blood flow is reduced so much that it is like a stroke or heart attack.
If that happens in the small arteries that supply the optic nerve, the nerve is damaged in the same way the cells on the other side of where a stroke or heart attack happens. It can happen slowly or suddenly - like the difference between angina and a real heart attack. If the blood flow stops suddenly because the gap was to small for even red blood cells to get through or because a small clot came along then that can cause fleeting loss of sight - or even longer if the blockage doesn't clear.
The nerve cells in the optic nerve are damaged - and may even die. Nerves don't regenerate like skin or other cells do to heal and get back to normal so once the amount of damage is too much the nerve is unable to carry signals from the retina at the back of the eye to the brain. So you can't see. And it cannot be reversed (yet).
Thanks flipdover for taking the time to show me that.I have been
wondering for awhile what was the cause.I occasionally have had
temporal headaches on my left side,sensitivity to my scalp when
I get the headache.I just recently went through a short trial of
pred to see if it would help with my pmr symptoms and one of the
side effects from the pred was blurry vision which just got me to
wondering what the connection was with gca and blindness.
I will read more of the leaflet so to get more of an understanding
Wow,between yours and flipdovers help,I have a much better
understanding which is what I needed.I have an appt in a few weeks
with my rheumy and I want as much information as I can get
beforehand.Since I took a weeks worth of pred to sort out my
pmr type symptoms, during that week I had no pain or fatigue
but did have some blurry vision at times from the pred.
Which was why asking on gca because besides the pmr symptoms
I have had left sided temporal headache,jaw ache and tightness.
If my rheumy determines I have pmr and the pred causes
blurriness as a side effect what else can be taken? Or does that
ease up after taking awhile?
Pred is currently the only option for GCA and PMR. It is possible there will be an alternative for GCA in the relatively near future but it is unlikely to be used generally for PMR as it is very expensive.
Certainly, taking pred and finding all the symptoms gone could support a diagnosis of PMR - depending on the dose you were given. High doses will relieve other problems too.
Don't forget to mention the jaw pain - making a bullet list now as things happen can be very useful so you don't forget while at the rheumatologist.
It is possible that the blurry vision would improve as your body got used to pred - the only way to find out is to try. I found I could manage well by simply moving my glasses up and down my nose!
On this site are the BSR Guidelines for the Diagnosis and Treatment of GCA.
Also put PMR&GCAuk North East in your search engine, they are also on that website.
I was on a 6 day course.First day was 24 mg broken up
through out the day.2nd day was 20 and so on.
I am getting all my ducks in a row
Last time I went to dr's appt I remembered things too late
and had to call to make sure what I forgot got charted.
I will remember to adjust my glasses 
Great, thanks for the tip.I'll be sure to look it up
If you have GCA then a 6 day taper won't do much good - as soon as you stop the symptoms will be back. If the GCA-type symptoms are still there and if you develop ANY visual symptoms don't wait for the next appointment, especially if it is a few weeks away - get hold of a doctor immediately, same day if possible. Once visual symptoms appear in GCA that is a warning to get on with high dose pred. So ER is reasonable if your PCP won't help the same day.
Thanks Eileen,I will for sure head to the ER if I have problems
I have had a few bouts of pain in left temple that is very painful
and the tenderness is always there,which was why I wasn't sure
if it was possible gca.It's hard sorting out the symptoms.
But I know it isn't normal not to be able to finish singing a song
without both sides of my jaw hurting and throat feeling sore.
I had that sort of problem too although, strangely, it went away! The worst bit for me was the loss of breath control and then the sore throat meant I couldn't be sure the right note would emerge! I also had scalp pain. It, too, only lasted a few weeks and at the time I didn't know anything like what I know now! I spoke to a specialist experienced in those aspects of GCA and she said she'd never come across that sort of thing going away before. Once I was put on 15mg I never had a problem again.
It's impossible to know what yours is - but I certainly wouldn't rule out GCA so bear it in mind.
I suppose the specialists wouldn't hear about these things going away of their own accord, would they? Just like we don't really know how many PMR diagnosed people do, in fact, take their pred as prescribed, taper without incident and are effectively in remission in two years....
These things are a mystery aren't they.They come and they go
Hmmm, this is interesting. So is it possible to have GCA and it NOT affect the eyes?
Could you have it only in the chest, and not in the head?
These are rhetorical questions and I will find out for myself! :-)
Yes and yes. But perhaps unfortunately you can't say whether it is GCA that is causing it or some other form of inflammation - the only place you can prove GCA is in the temporal artery (it can be managed without) unless you have access to the aorta in open heart surgery - which isn't very practical! Or at post mortem - preferably not then! That why when they find inflammation using PET scanning it is usually called LVV, large vessel vasculitis. GCA is an LVV, not all LVV is GCA.
I wonder if the odds of one getting GCA increases with vericose
veins? I inherited from my mom who's hands and legs had
very hearty veins.
No connection at all - GCA affects arteries, not veins.
Thanks Eileen