What are Symptoms of GCA in body other than head ?

GCA can affect any artery that has an elastic layer in its wall - so it doesn't affect by any means all arteries. Most of the arteries that are affected are deep in the body - the thoracic aorta is the very large artery that takes blood away from the heart, then the arteries that branch off that to supply the body can also be involved. If the brachial artery is involved you will get pain in the arms when you use them - and it is very likely that that is also part of PMR. If the pulmonary arch is involved it is likely to lead to cough and throat symptoms.The arteries in the head (temporal, occipital, lingual, facial and ophthalmic) are the most commonly involved - the only one that was easy to see and do a biopsy on to prove GCA is the temporal artery and that is why the misapprehension has evolved that the only artery to worry about is the temporal artery and why it was called temporal arteritis. Involvement of the occipital artery leads to scalp pain, the lingual tongue pain, facial can affect the jaw and ophthalmic is the dangerous one as that indirectly supplies the optic nerve. Sometimes the aorta down as far as the abdomen can be affected and then the blood supply to the legs may be reduced if the branching arteries there have giant cells.

Until relatively recently it was only at autopsy that you could find artery walls that had the giant cells present - it is not possible to take a bit of these other arteries to examine except in a major operation. As a result it wasn't clear that many other arteries could be affected. In recent years imaging techniques have been developed so you can "see" which arteries are involved - PET-CT or PET-MRI are the best where a radioactive substance is injected and is taken up by the inflamed tissue and then shows up on the images. It is possible to see the brachial artery using ultrasound - that is the artery supplying the arms.

In PMR it is thought that the microcirculation is affected in some way - the very smallest blood vessels on the arterial side of the circulation so that the supply of oxygen to the muscles is reduced and the removal of waste products impeded. The details aren't yet clear but there is research being done at present.

What you can see on your abdomen is a vein - veins are never involved, they don't have an elastic part to the vessel wall. The same applies to the protruding vessels on the back of your hand - the artery is relatively deep in the wrist where your pulse can be felt and those on the back of the hand where they sometimes take blood or put a cannula in are veins.

The very high doses used for patients with visual symptoms are to reduce the swelling quickly to try to avoid loss of vision. You can't see how bad the blockage is so you have to go at it with a sledgehammer to crack the nut. Most experts feel that much lower doses will control the inflammation in other arteries - but the higher the dose the quicker it will be reduced. If vision is affected there isn't time to wait for a lower dose to work. Even in PMR it is known that a dose of 12.5mg is enough to get a result in 75% of patients within a month - 15mg does it quicker!

It is becoming clear that it is fairly likely that much of the severe arm and leg stiffness in PMR is really due to GCA - and it is in these patients that PMR happens before they develop any visual symptoms. Some people only ever show PMR symptoms, some people only show GCA symptoms affecting the arteries in the head - and some have a bit of both. However, it is not true to say that because you are on a low dose of pred you cannot develop temporal arteritis or cranial GCA. It all depends on how severe it is.