Giant cell arteritis (GCA)

Giant cell arteritis is a form of vasculitis, meaning the immune system mistakenly attacks the walls of the larger arteries, causing inflammation and swelling that narrows them and reduces the blood supply they carry. The name comes from the large inflammatory cells seen when an affected artery is examined under the microscope.

Why this happens is not fully understood, and there is no single known cause. A combination of immune and ageing-related factors is thought to be involved.

It almost always affects people over 50, becomes more common with age, and is seen more often in women. It is closely linked with polymyalgia rheumatica, and the two conditions can occur together or one after the other.

GCA can develop over days or weeks. Typical features include:

• A new, persistent headache, often around the temples
• Tenderness of the scalp, for example when brushing the hair
• Pain or fatigue in the jaw when chewing
• Changes in vision, such as blurring, double vision or loss of vision (which is an emergency)
• Sometimes the shoulder and hip stiffness of polymyalgia rheumatica, tiredness, or a raised temperature

Diagnosis is based on the symptoms, an examination and blood tests that usually show inflammation, supported by further investigations. Because of the risk to vision, treatment is often started promptly when GCA is strongly suspected, before all results are back.

Ultrasound of the affected arteries can help support the diagnosis by showing characteristic changes, and in some cases a biopsy of an artery is appropriate. Because GCA is a serious, sight-threatening condition, Dr Borukhson refers for dedicated specialist imaging, or a biopsy where appropriate, to confirm the diagnosis, and is happy to arrange this promptly.

GCA responds to steroid (corticosteroid) treatment, usually high-dose prednisolone tablets, started quickly to protect against complications and then reduced gradually over time under careful review. Where sight is threatened, treatment may begin in hospital with a steroid given through a drip (intravenous methylprednisolone). Prompt steroid treatment is the key to protecting vision and the other arteries that can be affected. Steroids should never be stopped suddenly, and a longer course usually includes bone protection and regular monitoring, all discussed fully with you. In some cases a biologic medicine called tocilizumab is added under specialist supervision to help control the inflammation and allow the steroid dose to come down sooner; because it can increase the risk of infection, its suitability is considered carefully. Because treatment continues for a while and needs monitoring, ongoing specialist input is valuable.

The plan is tailored to you and kept under regular review, with the dose adjusted as the condition settles.

GCA is best known for affecting the arteries around the temples, but in some people it also involves the larger arteries, including the aorta, the large vessel leaving the heart, and its branches to the head, neck and arms. This is known as large-vessel GCA. It often causes no symptoms of its own and comes to light on the specialist imaging used to investigate the condition.

The same prompt steroid course remains the foundation of treatment and settles the inflammation in these arteries too. Large-vessel GCA is, however, more likely to need a second medicine alongside the steroids, such as methotrexate or the biologic tocilizumab described above, particularly if the inflammation keeps returning as the steroid dose comes down. Over the years, an artery wall that has been inflamed can slowly stretch, a change called dilatation; rarely, this develops into an aneurysm, a bulge in the wall. For this reason, your team may arrange a scan of the aorta from time to time as part of long-term follow-up. This is precautionary follow-up rather than a cause for alarm. Changes of this kind develop slowly, if they happen at all, and an occasional check means anything that needs attention is picked up in good time.

Giant cell arteritis can affect the eyes and the larger blood vessels, so prompt, coordinated input from more than one specialty can be important. Dr Borukhson practises within a world-renowned tertiary centre, with ready access to consultant colleagues across the other specialties that may be involved in caring for this condition. Where appropriate, she can involve those specialists directly, and bring particularly complex cases to a multidisciplinary team meeting (MDT) with minimal delay. This means that, when more than one area of expertise is needed, your care can be joined up and decisions reached promptly.

GCA usually responds to treatment, but recovery takes time and the steroid course is a long one, so steady follow-up matters more than anything you do alone.

• Take steroids exactly as prescribed and never stop them suddenly, even when you feel well; carry a steroid card so other clinicians know.
• Attend monitoring appointments, which check that the inflammation stays controlled and watch for steroid side effects.
• Protect your bones with the calcium, vitamin D or bone treatment offered, plus weight-bearing activity as you are able.
• Eat well and stay active within comfort; steroids can affect weight, mood, sleep and blood sugar.

Most people improve steadily, though the dose comes down slowly. Tiredness and ups and downs are normal, so be patient with yourself.

The most important rule is to act quickly on anything affecting your sight. Any new or sudden change in vision, including blurring, double vision, a shadow or curtain across your sight, or loss of vision in one or both eyes, is an emergency. Sudden weakness in a limb or the face is also an emergency. Do not wait for a routine appointment; attend your nearest emergency department or call 999.

Seek urgent same-day advice, through your GP or 111, if you develop a new severe headache, scalp tenderness, or jaw pain when chewing.

Once treatment is under way, contact your team promptly if these symptoms return as your steroid dose reduces, or if you develop signs of infection such as fever, which steroids can mask.

The key message with GCA is not to delay. Prompt recognition and treatment greatly reduce the risk of serious complications. If you have the urgent symptoms described above, seek emergency assessment straight away rather than waiting for a routine appointment.

How urgently does suspected GCA need to be assessed?

Promptly, and without waiting for a routine appointment if there are urgent symptoms. GCA can affect the arteries supplying the eyes, and early treatment protects against serious complications including sight loss. New or sudden changes in vision, particularly with a new headache, scalp tenderness or jaw pain on chewing, need emergency assessment immediately.

Will treatment wait until all the test results are back?

No. Because of the risk to sight, steroid treatment is often started as soon as GCA is strongly suspected, before every result is available. Blood tests, specialist imaging of the arteries and, in some cases, an artery biopsy then help to confirm the diagnosis while treatment is already under way.

How long does steroid treatment for GCA continue?

The steroid course begins at a high level to bring the inflammation under control quickly, then reduces gradually under careful review; the full course is usually a long one. Steroids must never be stopped suddenly, and a longer course normally brings bone protection and regular monitoring with it. The pace of reduction is adjusted as the condition settles, and everything is discussed with you along the way.

What is tocilizumab and might I need it?

Tocilizumab is a biologic medicine added in some cases of GCA, under specialist supervision, to help settle the inflammation and let the steroid dose come down earlier. It is not needed by everyone, and because it can make infection more likely, its suitability is weighed carefully for each person. Whether it has a place in your treatment is discussed as part of your review.

Can GCA affect arteries elsewhere in the body?

Yes, sometimes. As well as the arteries around the temples, GCA can involve the larger arteries, including the aorta, the large vessel leaving the heart, and its branches to the head, neck and arms. This often causes no symptoms of its own and shows up on scans. Prompt steroid treatment settles the inflammation in these arteries too, though large-vessel GCA is more likely to need a second medicine, such as methotrexate or tocilizumab, alongside the steroids. Because an inflamed artery wall can slowly stretch over the years, your team may arrange a scan of the aorta from time to time. That is precautionary monitoring rather than a sign that anything is wrong.

When should I seek emergency help?

Any new or sudden change in your vision is an emergency: go to your nearest emergency department or call 999 rather than waiting for a routine appointment. A new severe headache, scalp tenderness or jaw pain when chewing without any change in vision still needs urgent same-day advice from your GP or 111.