Giant-cell arteritis

01OverviewDefinition, clinical context and the essential points that orientate the chapter.

GCA is granulomatous vasculitis of medium and large arteries in adults over fifty. Cranial branches of the carotid create the classic headache, scalp tenderness and jaw claudication pattern, but ophthalmic, vertebral, subclavian and aortic disease determine much of the serious harm. Some patients present mainly with PMR, fever, anaemia, weight loss, limb claudication or aortic inflammation. Examine temporal arteries, scalp, vision, ocular movements, pulses, bruits, blood pressure in both arms and aortic signs.

Treatment and confirmation run in parallel because preventable blindness can occur during diagnostic delay. For a strong uncomplicated suspicion, start oral prednisolone 40–60 mg daily. Visual symptoms require same-day ophthalmology and high-dose intravenous or oral rescue. Ultrasound performed by trained operators identifies a non-compressible halo and axillary involvement; biopsy shows transmural inflammation and can remain positive after treatment but sensitivity falls with time and skip lesions occur.

A negative cranial test does not end assessment when pre-test probability is high. Review imaging quality, biopsy length and timing and consider contralateral biopsy or extracranial imaging. Conversely, steroid response is not diagnostic because many painful and malignant conditions improve temporarily. Record the diagnostic probability and evidence before prolonged treatment. Large-vessel imaging is important for arm claudication, pulse disparity, persistent systemic inflammation or suspected aortic disease.

Glucocorticoid taper is deliberate, with disease and toxicity checks at each step. Tocilizumab reduces relapse and steroid exposure in eligible relapsing or refractory disease, but CRP and fever may be suppressed during both relapse and infection. Bone protection, vaccination, glucose, pressure, eye and infection care begin with the first high dose. Long-term surveillance includes aortic symptoms and a risk-based imaging plan rather than discharge when headache resolves.

Key points

Suspect GCA in anyone over fifty with new headache, scalp tenderness, jaw or tongue claudication, visual symptoms, abnormal temporal artery, PMR symptoms or unexplained inflammatory illness.
Ask every suspected patient explicitly about transient visual loss, diplopia and permanent change; visual symptoms move care to an immediate same-day pathway.
Give prednisolone 40–60 mg orally immediately for strongly suspected uncomplicated cranial GCA; do not wait for ESR, CRP, ultrasound or biopsy.
For acute or intermittent visual loss, give intravenous methylprednisolone 500 mg–1 g daily for up to three days under same-day specialist care, or oral prednisolone 60–100 mg if IV treatment would cause delay.
Obtain FBC, CRP, ESR, renal, liver, glucose and bone-risk baseline, but normal inflammatory markers do not safely override a convincing ischaemic phenotype.
Temporal and axillary artery ultrasound is the preferred rapid first diagnostic test in an experienced pathway; temporal-artery biopsy remains valuable when imaging is unavailable, discordant or diagnostic certainty remains important.
Ultrasound and biopsy sensitivity decline after glucocorticoid, so arrange within days, ideally within one week, without withholding treatment.
Use PET-CT, CTA or MRA for suspected extracranial large-vessel disease, unexplained systemic features or discordant cranial tests; each modality answers a different inflammation and anatomy question.
Taper glucocorticoid only after symptoms and markers respond, usually over at least one year; relapse requires reassessment for infection and confirmation of active vascular disease.
Consider tocilizumab with a planned steroid taper for relapsing, refractory or high-toxicity-risk disease under NICE and specialist criteria; IL-6 blockade suppresses CRP, so clinical monitoring changes.

02AetiologyUnderlying causes, associations and risk factors, with why each one matters.

Age-related immune susceptibility

GCA almost exclusively affects people older than fifty, with HLA and immune-ageing factors permitting granulomatous inflammation in medium and large arteries.

Environmental and geographic modifiers

Seasonal and northern-European patterns suggest environmental triggers in susceptible hosts, but no infection has been established as a routine treatable cause.

Shared PMR spectrum

Polymyalgia rheumatica and GCA frequently coexist through overlapping immune pathways; each patient must be screened for features of the other.

03PathophysiologyThe causal sequence from the underlying abnormality to symptoms and harm.

1
Arterial wall immune activation
Dendritic-cell activation recruits CD4 T cells and macrophages into the arterial media and adventitia, forming granulomatous inflammation and sometimes giant cells.
2
Intimal hyperplasia and stenosis
Cytokines and growth factors drive intimal proliferation, luminal narrowing and thrombosis, reducing flow to optic nerve, jaw, brain, limbs and aorta.
3
Ophthalmic ischaemia
Posterior ciliary artery occlusion causes arteritic anterior ischaemic optic neuropathy, often sudden and irreversible, with the untreated fellow eye at immediate risk.
4
Aortic remodelling
Persistent large-vessel inflammation weakens and scars the aortic wall, causing stenosis, aneurysm or dissection years after cranial symptoms resolve.

04Clinical features and red flagsSymptoms, examination findings, patterns of presentation and time-critical warnings.

Cranial artery pattern

New localised headache, scalp tenderness, thickened or reduced-pulse temporal artery and jaw claudication in an older adult strongly supports cranial GCA.

Visual ischaemiaRed flag

Amaurosis fugax, diplopia, field or colour loss and sudden permanent visual change requires immediate glucocorticoid and ophthalmic care.

Large-vessel phenotype

Arm claudication, pulse or pressure asymmetry, bruits, refractory systemic inflammation and aortic pain suggest extracranial arterial involvement.

PMR association

Bilateral shoulder and hip girdle stiffness may precede or accompany GCA; any new cranial or visual feature changes treatment urgency.

Occult systemic GCA

Fever, anaemia, weight loss and high markers without headache can represent aortic or large-vessel disease after infection and cancer are assessed.

Red flags requiring action

Amaurosis fugax, diplopia, colour or field loss and new visual impairment require immediate treatment and same-day ophthalmic assessment.
Jaw or tongue claudication, tongue infarction, scalp necrosis or an abnormal temporal artery indicates high cranial-ischaemic risk.
Stroke, limb claudication, pulse asymmetry, aortic pain or a new regurgitant murmur suggests large-vessel ischaemia or aortic complication.
Fever, weight loss or high inflammatory markers can reflect infection or malignancy; investigate alternatives while protecting vision when GCA is credible.
Normal ESR or CRP is uncommon but does not exclude a convincing visual or cranial presentation.

05InvestigationsWhat to request, why it matters and how to interpret it.

Investigation order

Read from the initial assessment onwards. Tests may run in parallel in urgent care; first-line, preferred, confirmatory, definitive and gold-standard labels appear only when the chapter explicitly states them.

01
Immediate visual and vascular examinationFirst step
Why
Identify threatened sight, cranial arterial abnormality and large-vessel asymmetry before treatment or transfer.
Interpretation and limitations
Record acuity, fields, pupils, fundi, diplopia, temporal pulse and tenderness, bruits, limb pulses and bilateral pressures; normal fundus does not exclude transient ischaemia.
02
FBC, CRP, ESR, renal, liver and glucose
Why
Support inflammatory probability, identify mimics and establish high-dose glucocorticoid safety baseline.
Interpretation and limitations
Thrombocytosis and anaemia support inflammation; normal CRP and ESR reduce but do not eliminate probability in a classic ischaemic presentation.
03
Temporal and axillary artery ultrasound
Why
Provide rapid non-invasive confirmation in a trained fast-track service.
Interpretation and limitations
A non-compressible halo supports arteritis; operator expertise, atherosclerosis and glucocorticoid timing affect sensitivity and specificity.
04
Temporal artery biopsy
Why
Obtain histological evidence when imaging is unavailable, negative despite suspicion or long-term diagnostic certainty matters.
Interpretation and limitations
Granulomatous transmural inflammation supports GCA, but skip lesions and treatment reduce sensitivity; request an adequate arterial length.
05
PET-CT, CTA or MRA
Why
Evaluate aortic and branch-vessel inflammation, stenosis, aneurysm and alternative disease.
Interpretation and limitations
PET reflects metabolic activity, while CTA and MRA define wall and lumen anatomy; glucocorticoid lowers inflammatory signal and atherosclerosis can confound.
06
Aortic surveillance imaging
Why
Detect delayed aneurysm or dissection in patients with large-vessel involvement or relevant symptoms.
Interpretation and limitations
Interval and modality are individualised because evidence does not support one universal schedule for every cranial-only case.

06Differential diagnosisRealistic alternatives and the features that help distinguish them.

Non-arteritic optic ischaemia

Sudden monocular visual loss with vascular risk and no inflammatory cranial phenotype may be non-arteritic AION, but urgent specialist distinction is essential.

Migraine and primary headache

Longstanding stereotyped episodes, aura and normal vascular examination favour migraine, while new headache after fifty requires secondary-cause evaluation.

Dental, TMJ and cervical disease

Pain with chewing can reflect temporomandibular or dental disease, but true jaw claudication is exertional fatigue or pain that settles with rest.

Infection and malignancy

Endocarditis, osteomyelitis, lymphoma and other cancer can cause fever, anaemia, weight loss and high markers and may worsen with empirical steroid.

07ManagementImmediate care, first-line treatment, alternatives and escalation.

01Immediate first-line treatmentProtect sight before confirmationFirst stepFirst lineClinical suspicion of GCA is strong, with no current visual symptom.

1Draw baseline bloods and assess visual, neurological and vascular status without delaying the first glucocorticoid dose.
2Start prednisolone 40–60 mg orally once daily and arrange fast-track rheumatology review and ultrasound within days.
3Use biopsy or extracranial imaging when ultrasound is negative or discordant and probability remains clinically important.

02Visual emergencyTreat and assess the fellow eyeTransient or permanent visual loss or diplopia occurs with suspected GCA.

1Give intravenous methylprednisolone 500 mg–1 g immediately and daily for up to three days; if IV access would delay care, give oral prednisolone 60–100 mg.
2Arrange same-day ophthalmology and acute rheumatology assessment, documenting both eyes and excluding retinal, embolic and neurological alternatives.
3Continue high-dose oral therapy after pulses and secure ultrasound or biopsy promptly without assuming established visual loss will reverse.

03Taper and relapseReduce exposure without losing controlSymptoms and inflammatory markers respond, or new compatible symptoms occur during taper.

1Maintain the initial dose until symptoms and markers resolve, then use the specialist taper with clinical and laboratory review at each major step.
2At suspected relapse reassess vision, vascular symptoms, infection, PMR, adrenal and steroid-withdrawal symptoms before raising treatment.
3Return to the last effective dose for confirmed relapse and consider tocilizumab or another steroid-sparing plan for repeated relapse or toxicity.

04Large-vessel follow-upProtect the aorta beyond headacheImaging shows aortic or branch-vessel disease, or new claudication and aortic symptoms develop.

1Define active wall inflammation and fixed structural damage with the appropriate PET, CTA, MRA and vascular examination.
2Control inflammation and ordinary cardiovascular risks and involve vascular or cardiothoracic teams for critical stenosis, aneurysm or dissection.
3Agree long-term imaging and symptom surveillance, including emergency advice for sudden chest, back or abdominal pain.

Key medicines and prescribing safety4 treatments · regimens, roles and cautions

First-line treatment that prevents further cranial ischaemia while diagnostic confirmation proceeds.

Prednisolone for uncomplicated GCA

Start 40–60 mg orally once daily immediately, maintain until symptoms and inflammatory markers resolve, then taper over at least twelve months using the specialist schedule.

Do not delay for testing. Check infection, glucose, pressure, mood, eyes and bone, provide gastric and Pneumocystis protection when total risk indicates, and never stop prolonged therapy abruptly.

Emergency treatment for acute or intermittent visual loss and other immediately organ-threatening cranial ischaemia.

Intravenous methylprednisolone for visual ischaemia

Give 500 mg–1 g intravenously once daily for up to three consecutive days, followed by high-dose oral prednisolone under same-day specialist care.

Monitor rhythm, pressure, glucose, electrolytes, psychiatric and infection effects. If IV treatment would delay care, give oral prednisolone 60–100 mg immediately.

IL-6 receptor blockade reduces relapse and cumulative glucocorticoid exposure in selected relapsing or refractory disease.

Tocilizumab

For eligible adult GCA, use 162 mg subcutaneously once weekly with a defined glucocorticoid taper under specialist prescribing; NICE-funded treatment is limited to a maximum of one year.

Screen TB, hepatitis and infection, check neutrophils, platelets, liver tests and lipids, and avoid live vaccines. CRP and fever may be suppressed during infection or relapse; review gastrointestinal perforation risk.

Prevents glucocorticoid-related fragility fracture when high-dose prolonged treatment creates sufficient risk.

Alendronic acid with calcium and vitamin D

When fracture risk and renal or oesophageal suitability support treatment, use alendronic acid 70 mg orally once weekly plus calcium and vitamin D sufficient for the individual diet and deficiency status.

Take fasting with plain water and remain upright for at least thirty minutes; avoid oesophageal emptying disorders and severe renal impairment, check calcium and vitamin D and provide dental risk advice. The 70 mg weekly regimen is off-label for some male or glucocorticoid-induced-osteoporosis product indications, so check the selected SmPC and formulary.

08ComplicationsImportant consequences, why they occur and why they matter clinically.

Permanent visual loss

Arteritic optic neuropathy, retinal artery occlusion and posterior circulation ischaemia can cause irreversible unilateral then bilateral blindness.

Stroke and peripheral ischaemia

Vertebrobasilar stroke, tongue infarction, upper-limb stenosis and limb claudication arise from cranial or extracranial arterial narrowing.

Aortic aneurysm and dissection

Large-vessel involvement increases delayed thoracic and abdominal aneurysm, aortic regurgitation and dissection risk, requiring long-term symptom and imaging strategy.

Glucocorticoid toxicity

Diabetes, infection, osteoporosis, cataract, glaucoma, mood change, myopathy and adrenal suppression accumulate during prolonged treatment and repeated relapse courses.

09Monitoring and follow-upTreatment response, safety checks and longer-term review.

Review within days after diagnosis and at each taper step for headache, jaw, scalp, vision, neurological, limb and PMR symptoms and glucocorticoid toxicity.
Trend CRP, ESR, FBC, glucose and organ safety, but recognise IL-6 blockade makes inflammatory markers unreliable for relapse and infection.
Measure pressure, weight, HbA1c or glucose, bone risk, eye health, mood, muscle strength and infection throughout prolonged glucocorticoid exposure.
Confirm ultrasound, biopsy and imaging ownership and revisit diagnosis when all tests are negative or the response trajectory is atypical.
Ask about arm claudication, pulse changes and chest, back or abdominal pain long term and follow the agreed aortic imaging plan.
Provide a steroid card and explicit emergency route for any new visual symptom, stroke feature or aortic pain.

10Special situationsVariants, exceptions and circumstances that change the usual approach.

Treatment precedes proof

The consequence of a short diagnostic delay is irreversible bilateral blindness, while ultrasound and biopsy can still be arranged after immediate steroid.

Jaw claudication is exertional

Ischaemic jaw discomfort builds during chewing and settles with rest, unlike constant dental or temporomandibular pain.

One eye warns the other

Established visual loss often does not recover, but immediate treatment protects the fellow eye and prevents further vascular events.

CRP can be pharmacologically silent

Tocilizumab blocks IL-6 signalling, so infection and vascular relapse require clinical assessment even when CRP remains low.

GCA extends beyond temples

Aortic and subclavian disease can dominate or emerge later, requiring pulse, pressure and structural surveillance after cranial symptoms settle.

11Common pitfallsFrequent interpretation and management errors.

01
Waiting for ESR, CRP, ultrasound or biopsy before giving glucocorticoid in a strong clinical presentation.
02
Treating transient visual loss as routine migraine in an older patient with new cranial symptoms.
03
Using steroid response as proof of GCA and overlooking infection or malignancy.
04
Abandoning diagnosis after one negative temporal biopsy despite high pre-test probability and possible large-vessel disease.
05
Monitoring tocilizumab-treated disease with CRP alone.
06
Stopping follow-up when headache resolves and missing aortic aneurysm or dissection risk.