Giant cell arteritis (GCA) is a common inflammation disease of medium- to large-sized arteries. These arteries can become narrowed, restricting blood flow to affected parts of the body. Giant cells are immune cells found in high concentrations inside affected arteries.
Arteries in the head are the most commonly affected, but arteries in the chest, neck, heart, and other parts of the body may also be involved. When the arteries in the temples of the head are affected, it is termed temporal arteritis or cranial arteritis.
There are 3 patterns seen in giant cell arteritis:
- primarily affecting the head
- primarily affecting the larger vessels of the chest and neck
- a wasting, generalized disease
GCA is unusual in people under 50 years of age. The average age for it to start at is 70. Two-thirds of people who have giant cell arteritis are women. People of African descent are less commonly affected.
GCA is closely associated with a disease called polymyalgia rheumatica (PMR), which many experts believe is a different manifestation of the same underlying disorder. 10% to 20% of people with PMR develop GCA.
More than 50% of people with GCA also have the symptoms of PMR. Fortunately, the same treatment is effective for both conditions, but GCA requires much higher doses.