Giant cell arteritis (GCA) is the most common form of vasculitis that occurs in adults. Almost all patients who develop giant cell arteritis are over the age of 50. GCA commonly causes headaches, joint pain, facial pain, fever, and difficulties with vision, and sometimes permanent visual loss in one or both eyes.1 The disease can cause so many different symptoms that the diagnosis of GCA can be difficult to make.
Giant cell arteritis is a disease characterised by inflammation of large and medium-sized blood vessels. An alternative name for this condition is temporal arteritis as the blood vessels in the temple area of the head (sides of the forehead) are commonly affected. The giant cells referred to are specific collections of immune system cells seen in the areas of inflammation if a biopsy is performed.2
It involves the major branches of the aorta with predilection for the extracranial branches of the carotid artery. It occurs in individuals older than 50 years and the incidence increases with age. The signs and symptoms of giant cell arteritis can be classified into four subsets: cranial arteritis, extracranial arteritis, systemic symptoms and polymyalgia rheumatica.3
This condition is one of the commonest forms of vasculitis, affecting one or two persons per 10,000 people in the UK. It is more commonly seen in older patients and is seldom diagnosed below the age of 50 years.
GCA is quite often associated with a condition called polymyalgia rheumatica (PMR), which causes severe stiffness of the muscles, particularly in the shoulders and hips. About 15% of PMR patients also develop GCA, while 40–50% of people with GCA also have symptoms of PMR.4
As with most types of vasculitis there is no one test that will give the diagnosis. The only test that confirms GCA diagnosis is a temporal artery biopsy, showing vasculitis with mononuclear cell inflammatory infiltrates, often with giant cells. Due to the focal and segmental nature of the infiltrates, areas of inflammation may be missed by the biopsy and the histological examination is normal in about 15% of the cases.
Some imaging modalities may aid in the diagnosis of GCA. Among those, color duplex ultrasonography of the temporal arteries is more commonly used.3
A diagnosis often only occurs if the physician recognises the typical collection of symptoms and clinical signs.
The clinical features of GCA can be classified into: (1) the systemic manifestations of malaise, weight loss, fever, night sweats and depression; (2) the proximal muscle pain and stiffness of polymyalgia rheumatica; (3) arteritic manifestations of pain or tenderness due to local inflammation; and (4) arteritic manifestations of ischaemia due to narrowing or occlusion of vessels. These may occur singly or in any combination and may come and go with the passage of time. Thus GCA can result in many different clinical signs and symptoms.5
The two aims of treatment are to relieve patients’ symptoms and prevent damage to organs (especially the eyes) due to reduced blood supply. High dose oral steroids (prednisolone) are usually given and the dose is reduced slowly over months, using the erythrocyte sedimentation rate (ESR) marker as a guide to response. Treatment with steroids is usually given for at least one or two years.2
Almost all patients experience side effects from prednisone. After the patient improves, the doctor gradually reduces the prednisone dose. The rate of tapering prednisone depends on how the patient feels, what the doctor finds on exam, and the results of blood tests, including the sedimentation rate. Although virtually all patients are able to reduce their prednisone dose, most require some amount of prednisone for 1–2 years. Longer treatment periods are not uncommon.1
In some patients with resistant or problematic disease other drugs are sometimes used such as methotrexate, azathioprine or antibody therapy such as infliximab. While some patients may respond well to these drugs, there is no current evidence that they are effective in all patients.2
There is a relapse rate of about 50%. Withdrawal of the steroids can lead to a relapse of the symptoms. In such cases the steroid is re-started and it is often sufficient to induce remission. The steroid dose can again be reduced. In most relapsed cases the patient will be maintained on a small maintenance dose of steroids indefinitely. The prognosis is good with correct and early diagnosis and treatment.
Damage to the eyes is usually the most serious complication. Involvement of the ophthalmic artery and its branches results in visual loss, which is often complete but is usually painless. Visual loss may be monocular or binocular developing simultaneously or sequentially. Rarely, it stems from occipital lobe infarct that result in homonymous hemianopia, a visual field defect involving the two identical halves (right or left) of the visual fields of both eyes. Visual hallucinations and diplopia are less common. All visual symptoms, including those that are transient, require urgent ophthalmological evaluation and treatment with high-dose glucocorticoids to avoid permanent visual loss.6
Before the advent of glucocorticoid treatment, the prevalence of visual complications was high. Increasing awareness by physicians of the symptoms of GCA and advances in diagnostic techniques over the past 20 years have also contributed to a substantial decline in the frequency of permanent visual loss.7
Ischaemic brain lesions are less common than visual lesions, and mostly result from vasculitis of the extradural vertebral or carotid arteries. In the case of both the eye and the brain, ischaemic damage is thought to result from arterial stenosis or occlusion that occurs secondary to the inflammatory process.7
Another complication highlighted in the case study is scalp ulceration. Scalp necrosis associated with giant cell arteritis was first described in the 1940s. The presence of this dermatological sign within giant cell arteritis represents a severity marker of this disease, with a higher mean age at diagnosis, an elevated risk of vision loss and tongue gangrene, as well as overall higher mortality rates, in comparison to patients not presenting this manifestation. Even though scalp necrosis due to giant cell arteritis is exceptional, a high level of suspicion must be held for this clinical finding, in order to initiate prompt and proper treatment and avoid blindness.8
Giant cell arteritis can begin suddenly or gradually with non-specific symptoms. Doctors should have a high degree of suspicion if a patient presents with any combination of the following symptoms: malaise, weight loss, depression, and fatigue or with the classic symptoms of headache, scalp tenderness, jaw claudication, visual changes, or polymyalgia rheumatica.
Alison Bloomer, Managing editor, GM
Conflict of interest: none declared
1. https://www.hopkinsvasculitis.org/types-vasculitis/giant-cell-arteritis/ (accessed 31/07/18)
2. http://www.vasculitis.org.uk/about-vasculitis/giant-cell-arteritis-temporal-arteritis (accessed 31/07/18)