Modern Assessment of Giant Cell Arteritis: Why Speed, Expertise and the Right Tests Matter
Giant cell arteritis, often shortened to GCA, is one of the few conditions in rheumatology where delay can have permanent consequences.
It is an inflammatory disease of medium and large arteries, usually affecting people over the age of 50. The arteries supplying the scalp, jaw and eyes are commonly involved, but inflammation can also affect larger vessels in the chest, neck and arms.
The most serious immediate concern is reduced blood supply to the eye, which can cause sudden and irreversible loss of vision. GCA can also cause stroke and other vascular complications. This is why suspected GCA must be treated as a medical and rheumatological emergency.
Modern assessment combines speed with careful clinical reasoning. The diagnosis is not made from one symptom, one blood test or one scan. It depends on bringing together the history, examination, inflammatory markers, expert vascular imaging and, in selected cases, temporal artery biopsy.
The aim is to treat patients at genuine risk without delay, while avoiding unnecessary prolonged steroid treatment in people whose symptoms have another cause.
Why is GCA a medical emergency?
Inflammation in GCA can narrow or block arteries supplying the optic nerve and other structures within the eye. Once established visual loss occurs, recovery is often limited.
Warning symptoms can include:
temporary or permanent loss of vision
blurring of vision
double vision
a shadow or curtain moving across the visual field
jaw or tongue pain when chewing
a new, persistent headache
scalp tenderness
Visual symptoms may initially be brief or intermittent before more permanent damage occurs. A transient episode of visual loss should therefore not be dismissed simply because the sight returns.
Anyone with suspected GCA and new visual loss, transient visual loss or double vision needs immediate emergency assessment. They should not wait for a routine outpatient or private appointment.
When the clinical suspicion is sufficiently high, glucocorticoid treatment is usually started immediately. Blood tests and diagnostic investigations should be organised urgently, but treatment should not be delayed while waiting for them if vision is at risk.
The clinical history remains central
Modern imaging has transformed GCA assessment, but the history still comes first.
A careful assessment looks for more than headache alone. Important symptoms include:
a new or changed headache in someone over 50
scalp tenderness, including discomfort when brushing the hair
jaw claudication, particularly aching or fatigue when chewing
tongue pain or claudication
visual disturbance
constitutional symptoms such as fever, night sweats, weight loss or profound fatigue
symptoms of polymyalgia rheumatica, including pain and stiffness around the shoulders and hips
arm pain or fatigue with use, which may suggest large-vessel involvement
neurological symptoms or previous vascular events
Not everyone has the classic presentation. Some patients have little or no headache. Others present predominantly with visual symptoms, polymyalgia, unexplained systemic inflammation or features of large-vessel disease.
Conversely, headache and raised inflammatory markers are both common and have many possible causes. The challenge is to judge how well the complete pattern fits GCA.
What does the examination add?
Examination may identify supportive features and help assess the risk of immediate complications.
This can include:
tenderness, thickening or reduced pulsation of the temporal arteries
visual and neurological assessment
listening for vascular bruits
checking pulses in both arms
comparing blood pressure between the arms
examining for features of polymyalgia rheumatica
looking for another explanation for the symptoms
A normal temporal artery examination does not exclude GCA. Large-vessel inflammation may occur without obvious abnormalities over the temples, and arterial inflammation can be patchy.
Which blood tests are useful?
The main inflammatory markers are C-reactive protein and the erythrocyte sedimentation rate. A full blood count may show anaemia or a raised platelet count, and liver tests may show an elevated alkaline phosphatase.
Blood tests are useful because they help support the clinical assessment and provide a baseline from which to monitor response. Where practical, they should be taken before glucocorticoids are started, but obtaining blood must not delay urgent treatment.
Blood tests do not diagnose GCA on their own.
Very high inflammatory markers may strengthen suspicion, but infection, malignancy and other inflammatory diseases can produce similar results. Normal inflammatory markers make GCA less likely, but exceptionally they do not completely exclude it when the clinical presentation is otherwise convincing.
Temporal and axillary artery ultrasound
Vascular ultrasound has become a central part of modern GCA assessment.
An expert ultrasound examination can identify characteristic inflammation and thickening in the arterial wall, often referred to as a halo. Modern assessment should generally include the axillary arteries as well as the temporal arteries because GCA may extend beyond the vessels of the head.
Ultrasound has several advantages:
it is non-invasive
it can usually be performed quickly
several arteries can be assessed during the same examination
it can provide immediate evidence to support or weaken the diagnosis
it avoids the need for an invasive procedure in some patients
However, access to an ultrasound machine is not enough. The examination is technically demanding and is only as useful as the expertise of the person performing and interpreting it.
Timing also matters. Glucocorticoid treatment gradually reduces the inflammatory changes visible on imaging. Ultrasound should therefore be arranged promptly, but treatment should not be withheld in a high-risk patient simply to preserve the scan result.
When is temporal artery biopsy still needed?
Temporal artery biopsy remains useful in selected cases.
A small section of the artery is removed and examined under a microscope for evidence of arteritis. Biopsy may be particularly helpful when:
ultrasound is unavailable
ultrasound findings are inconclusive
the scan and clinical assessment do not agree
histological confirmation would materially influence long-term treatment
an alternative diagnosis remains possible
A positive biopsy can provide strong diagnostic confirmation. However, a negative biopsy does not always exclude GCA. Arterial inflammation can be segmental, meaning that the sampled part of the artery may be unaffected even when disease is present elsewhere.
Biopsy should therefore be interpreted alongside the history, examination, blood tests and imaging rather than treated as an isolated final answer.
Looking beyond the temporal arteries
GCA is a large-vessel vasculitis and is not always confined to the arteries around the temples.
When extracranial or aortic involvement is suspected, further imaging may include:
axillary and other large-artery ultrasound
FDG PET-CT
MR angiography
CT angiography
specialist vascular MRI
These tests may be considered when there are symptoms such as arm claudication, unequal pulses, vascular bruits, marked constitutional illness or unexplained inflammation without typical cranial symptoms.
PET-CT can identify metabolically active inflammation in larger arteries. CT and MR angiography can provide more detailed information about the arterial lumen and complications such as narrowing, occlusion, dilatation or aneurysm.
The appropriate test depends on the clinical question. More imaging is not automatically better; the investigation should be selected because it is likely to affect diagnosis, monitoring or management.
Why treatment cannot always wait for confirmation
The immediate balance in suspected GCA is between two competing risks.
On one side is the danger of untreated arteritis, including permanent visual loss. On the other is the harm that can result from prolonged high-dose glucocorticoid treatment if the diagnosis is incorrect.
This is why rapid specialist assessment matters so much.
Where the clinical probability is high, particularly when visual symptoms are present, treatment should begin immediately. Investigation should then proceed urgently and in parallel.
Where the probability is lower or the presentation is atypical, prompt expert review and vascular imaging may prevent unnecessary months of steroid exposure.
The goal is neither to undertreat dangerous disease nor to prescribe high-dose steroids indiscriminately. It is to make a timely, proportionate decision based on the entire clinical picture.
What happens after the diagnosis?
Glucocorticoids remain the main immediate treatment for GCA. Once the disease is controlled, the dose is usually reduced gradually over time.
Modern management does not stop at prescribing steroids. It also involves:
monitoring symptoms and inflammatory markers
looking for relapse
reducing cumulative steroid exposure
protecting bone and metabolic health
assessing cardiovascular risk
considering large-vessel involvement
deciding whether steroid-sparing treatment is appropriate
Relapse is not uncommon, and prolonged glucocorticoid treatment can contribute to osteoporosis, diabetes, weight gain, hypertension, infection and other complications.
A structured follow-up plan is therefore essential.
What is the role of biologic treatment?
In selected patients, biologic treatment can form an important part of modern GCA care.
Tocilizumab targets the interleukin-6 pathway and can help maintain remission while reducing cumulative exposure to glucocorticoids. It may be particularly relevant in relapsing or refractory disease, or where the risks of prolonged steroid treatment are substantial.
It is not required for every patient. The decision depends on the disease course, previous relapse, comorbidities, steroid toxicity, infection risk and the applicable access or funding criteria.
Specialist access matters because biologic treatment requires:
a clear diagnosis
careful patient selection
appropriate infection screening
blood-test monitoring
a planned glucocorticoid reduction strategy
and ongoing assessment for relapse or treatment complications
The availability of biologic treatment also reinforces why GCA should not be viewed simply as a condition treated with a course of steroids and then forgotten. For some patients, it requires longer-term specialist management.
Why experience with GCA pathways matters
GCA assessment works best when the pathway is designed around speed.
Patients need rapid triage, expert clinical assessment, prompt blood tests and timely access to vascular imaging or biopsy. At the same time, treatment must not be delayed in patients at immediate risk of visual complications.
I have helped design and run GCA services within the NHS, bringing together urgent clinical review, laboratory assessment, imaging and treatment decisions. This pathway experience is valuable because the difficulty is not simply obtaining an ultrasound or ordering blood tests. It is coordinating the entire assessment quickly and interpreting the results as a whole.
It is particularly helpful when:
symptoms are atypical
inflammatory markers are only mildly abnormal or normal
ultrasound findings are uncertain
the clinical history and imaging appear to conflict
large-vessel disease is suspected
or there is uncertainty about continuing glucocorticoids or introducing steroid-sparing treatment
My dual training in rheumatology and general internal medicine also supports a broader assessment. Headache, visual symptoms, fever, weight loss and raised inflammatory markers can have several medical causes, and it is important to consider infection, malignancy, neurological disease and other vascular or inflammatory conditions where appropriate.
Working within a tertiary-centre environment also provides regular exposure to complex, multisystem and diagnostically uncertain inflammatory disease.
Can private assessment help?
For patients without acute visual symptoms, rapid private rheumatology assessment may sometimes help clarify whether the history is genuinely suggestive of GCA, arrange appropriate blood tests and imaging, and coordinate the next steps.
The value is not simply in doing more tests. It lies in:
estimating the clinical probability
arranging the right investigation quickly
interpreting the history, blood tests and imaging together
deciding whether treatment is needed immediately
and developing a safe longer-term plan if GCA is confirmed
However, private assessment should never delay emergency care.
New visual loss, transient visual loss, double vision or other sight-threatening symptoms require immediate emergency assessment.
The bottom line
Giant cell arteritis is a medical and rheumatological emergency because delayed treatment can result in irreversible visual loss and other vascular complications.
Modern assessment combines:
a detailed clinical history
careful examination
urgent blood tests
expert temporal and axillary artery ultrasound
biopsy where needed
and wider vascular imaging in selected cases
No single test should be interpreted in isolation.
The most important elements are speed, expertise and coordination. Treatment may need to begin before every investigation is complete, while rapid specialist assessment helps distinguish genuine GCA from its mimics and reduces the risk of both undertreatment and unnecessary prolonged glucocorticoid exposure.
When GCA is confirmed, modern care also includes structured follow-up, steroid-risk management and specialist access to biologic treatment where appropriate.
Related reading
Giant Cell Arteritis (GCA): Symptoms, Diagnosis and Treatment
Polymyalgia Rheumatica (PMR) Explained: Symptoms, Diagnosis and Treatment
Steroids Explained: Benefits, Risks and How They Are Used Safely in Rheumatology
Please note, these posts are for general information only and do not constitute medical advice. Dr Singh would encourage you to speak to your healthcare professional to be assessed and managed for your specific symptoms.