Temporal arteritis is a form of vasculitis, which means blood vessel inflammation. This is the immune system causing and reacting to damaged blood vessel lining.
The condition is diagnosed mostly in middle-aged people, after the age of around 50. The chances of temporal arteritis go up with increasingly older age.
Different countries have varying rates of the condition, and temporal arteritis is two or three times more likely to affect women than men.
Medical treatment is important because, without it, some cases lead to loss of vision.
What are the temporal arteries?
There are two temporal arteries, one on each side of the head. Each one runs over the part of the skull that is above and around the ear. The two arteries themselves run up in front of the ear.
The temporal arteries are important ones that branch off from the two main blood supplies to the head from the heart.
While the temporal arteries are usually affected, temporal arteritis is a condition that can also affect other medium and large arteries. These are also usually in the head and neck.
Temporal arteritis is also known as giant cell arteritis. It sometimes gets called cranial arteritis and was once known as Horton disease.
Symptoms of temporal arteritis
The main symptoms of temporal arteritis are:
- Severe headache
- Muscle pain in the head
The pain is severe and lasting. It usually occurs around the side of the head where the arteries are.
Further symptoms include:
- Tender temples
- Generaltiredness and weakness
- Mouth-related pain, especially affecting the jaw
- Pain affecting the tongue, throat, or face
- Pain or swelling on top of the head, or scalp
- Blurry or double vision
Any of these symptoms should be taken to a doctor for diagnosis and treatment. This is important whether the headache and other symptoms turn out to be caused by temporal arteritis or something else.
Complications of temporal arteritis
The most serious problem that can be caused by temporal arteritis is blindness. Loss of vision in the eye because of this condition is rare overall, however.
This complication may occur if the vasculitis affects an artery that supplies an eye.
If treatment for temporal arteritis is started before any effect on vision, the risk of blindness happening later is reduced to 1 percent or lower.
Other artery complications such as excessive swelling can also happen on rare occasions.
Diagnosis of temporal arteritis
It is important to see a doctor with any symptoms that could be temporal arteritis.
Doctors start out by following the symptoms described. They ask questions and will explore other possibilities. They will also do a physical examination.
If the doctor thinks it is temporal arteritis, they should start treatment right away.
The diagnosis is made clear by a lab analyzing a sample of the artery wall. A piece of the artery is removed under local anesthetic. Blood tests may also be ordered.
What are giant cells?
Giant cell arteritis is another name for temporal arteritis. This is because of what can happen to the lining of the arteries. In many cases of temporal arteritis, the inflammation of the blood vessel lining shows the formation of “giant cell” lesions.
These giant cells are from numerous immune cells fusing together. These immune cells are a type of white blood cell.
Temporal arteritis involves other immune cells and biological features of inflammation, however. As such, it does not always show these giant cell lesions.
Giant cell lesions form in about half of temporal arteritis cases. As a result, the condition can be diagnosed without giant cells being found.
Causes of temporal arteritis
Why some people develop temporal arteritis is not fully understood. It is also unclear why some groups are more at risk than others.
Aging is a risk factor, although it is not clear why. Geography, seasonal factors, and viruses have been linked, too.
Very few cases are associated with causes like an allergic reaction to drugs or toxins. TheNational Heart, Lung, and Blood Institute state that this can sometimes be the case, adding that the possibility that a recent or ongoing infection “may prompt the attack.”
Temporal arteritis and polymyalgia rheumatica
Polymyalgia rheumatica is a form of inflammation that affects the whole body. It causes muscle pain. Like temporal arteritis, it is also more common in older people over 50 and affects more women than men.
According to Arthritis Research UK, about 1 in 5 cases of polymyalgia rheumatica are accompanied by temporal arteritis.
Experts also estimate that up to 60 percent of people with temporal arteritis show symptoms of polymyalgia rheumatica.
Temporal arteritis and systemic vasculitis
Systemic vasculitis is related to temporal arteritis simply because the inflammation of head arteries is one form of vasculitis.
Systemic vasculitis is a collection of different disorders. All involve inflammation and damage to blood vessel walls that can lead to tissue death.
The different types are classified and managed according to the blood vessel size affected – large, medium, or small – and the area of effect, such as on an organ.
With temporal arteritis, the arteries affected are medium and the eye is at risk.
The general treatment approach for temporal arteritis is the same for all forms of vasculitis.
Why Minnesotans are more likely have temporal arteritis
People with a northern European background show a higher risk of developing temporal arteritis.
One study into rates of temporal arteritis in the United States looked at where the population is largely made up of that ethnic background – Minnesota.
The exact cause of this higher rate for northern European background is not fully understood.
Studying Olmsted County in particular, the researchers found that the rate here was as high as in Sweden, a country with one of the highest rates of temporal arteritis.
Over a 50-year period, the study found that there were almost 20 cases for every 100,000 in people across that time. The authors compared this with the rates in the Mediterranean region, where temporal arteritis is at its very lowest in northern Italy. There, the rate is at 6.9 per every 100,000 people.
The authors wrote that the north-south divide was “evocative of environmental causes, but could also reflect a genetic or ethnic influence.”
So average rates of temporal arteritis in the population overall are relatively low – although they get considerably higher in older people. While the rate is doubled in populations like Olmsted County’s, this is still twice what is a relatively low level in the first place among the overall population.
Treatment for temporal arteritis
A doctor will usually want to start treatment straight away. High-dose corticosteroid drugs are the treatment for temporal arteritis and they prevent complications such as loss of vision.
The medication should be offered before the diagnosis is confirmed. Primary care doctors are advised to issue the prescription rather than wait for a biopsy to be done.
The management may then be taken on by specialist doctors. Whichever doctors are helping with temporal arteritis, steroid treatment is a long-term one. The once-daily dose of 40 to 60 milligrams, by mouth, is gradually reduced after a number of weeks.
If loss of vision is suspected, a drug called prednisolone is given. Otherwise, a drug called prednisone usually needs to be continued for over 2 years. Daily low-dose aspirin is also recommended as a preventive effort against blood clots.
Written by Markus MacGill