Giant cell arteritis is an inflammatory condition affecting arteries of the upper body and head. Symptoms include headaches and blurred or double vision. Prompt treatment is required to reduce the risk of serious complications including stroke, blindness and abdominal aortic aneurysm.
The temporal arteries on the side of the head are most commonly affected and, for this reason, the condition is also known as temporal arteritis or cranial arteritis.
Causes and risk factors
The cause of giant cell arteritis is not fully understood. It is thought the inflammation may be due to an autoimmune reaction, where the body’s immune system mistakenly attacks normal, healthy tissue.
Giant cell arteritis is associated with a condition called polymyalgia rheumatica (PMR). PMR causes pain and stiffness in the muscles — particularly in the neck, shoulders, and back. Approximately 50% of people with giant cell arteritis have underlying PMR. The incidence of giant cell arteritis increases with age. It is seldom seen in anyone under the age of 50 years and the average age of onset is 75 years. It most commonly affects New Zealanders of Northern European decent and only rarely occurs in people of Asian descent. The condition is two- to three-times more likely to develop in women as it is in men.
Signs and symptoms
Symptoms include headaches and blurred or double vision, which is the result of inflammation causing the lining of affected arteries to swell to such a degree that blood flow is reduced or blocked.
The condition usually begins with mild flu-like symptoms including mild fever and a persistent dull headache. Specific signs and symptoms, which depend on the arteries affected, may include:
- Jaw pain — particularly when chewing
- Hearing problems
- Vision problems eg: blurred or double vision, loss of visual field
- Aching muscles about the neck and shoulders
- Loss of appetite
Other symptoms can include tenderness of the scalp, cough, throat pain, tongue pain, and weight loss. There may also be visible swelling of the arteries on the side of the forehead.
Symptoms may be vague at first, with a feeling of being generally unwell. Some patients have many symptoms; others have only a few. Symptoms tend to worsen as the condition progresses.
Diagnosis is sometimes difficult because the symptoms of giant cell arteritis can mimic the symptoms of other conditions.
To differentiate giant cell arteritis from other conditions it may be necessary to surgically remove a small sample (biopsy) of the affected artery for visual examination of signs of inflammation under a microscope. The sample will often show abnormally large cells, called giant cells, which give the disease its name. The biopsy is done under local anaesthesia.
Blood tests that identify inflammation in the body or unusual levels of a specific protein may indicate giant cell arteritis is present. The inflammation test can also be performed to help monitor the progression of the disorder.
Imaging tests, possibly including magnetic resonance angiography (MRA), doppler ultrasound, or positron emission tomography (PET) may be used to aid diagnosis and monitor the response to treatment.
If giant cell arteritis is left untreated there is a risk of blindness and stroke due to impaired blood flow to the eyes and brain as well as aortic aneurysm (including abdominal aortic aneurysm) due to weakened blood vessels. So, once a diagnosis of giant cell arteritis has been made, treatment is started as soon as possible to reduce the risk of complications.
Corticosteroid medications — usually prednisone — are the main form of treatment. The dosage will depend on the nature and severity of symptoms experienced.
High doses of corticosteroid medications are usually required until symptoms improve. After this initial period, the dosage is usually gradually reduced to the lowest dose at which symptoms are controlled. Treatment continues until the condition has completely resolved — in some patients this is as long as two to five years. Sometimes a low-dose treatment is required indefinitely.
The symptoms of giant cell arteritis can recur or "flare". In these cases, high-dose corticosteroid treatment will be resumed and immune system-suppressing medications such as methotrexate may be prescribed.
Treatment with high doses of corticosteroids can cause side effects, including high blood pressure and bone loss. Bone density monitoring will be recommended. Calcium and vitamin D supplements as well as bone-preserving medications will be prescribed to protect against osteoporosis and the risk of fractures.
A man-made biologic medication that blocks the inflammation process might also be used to treat giant cell arteritis.
American College of Rheumatology (2019). Giant cell Arteritis (Web page). Atlanta, GA: American College of Rheumatology Association of Rheumatology Health Professionals Rheumatology Research Foundation. https://www.rheumatology.org/I-Am-A/Patient-Caregiver/Diseases-Conditions/Giant-Cell-Arteritis [Accessed: 25/11/20]
Mayo Clinic (2020). Giant cell arteritis (Web page). Rochester, MN: Mayo Foundation for Medical Education and Research. https://www.mayoclinic.org/diseases-conditions/giant-cell-arteritis/symptoms-causes/syc-20372758 [Accessed: 25/11/20]
Seetharaman, M. (2020). Giant cell arteritis (temporal arteritis) (Web page). Medscape Drugs and Diseases. New York, NY: WebMD LLC. https://emedicine.medscape.com/article/332483-overview [Accessed: 25/11/20]
Last Reviewed: December 2020