Giant Cell Arteritis (GCA): Symptoms, Diagnosis and Treatment
Giant cell arteritis (GCA), also known as temporal arteritis, is a serious inflammatory condition that affects medium and large arteries, particularly those supplying the head, eyes and brain. It is a medical emergency because untreated disease can lead to permanent vision loss, stroke and other life-threatening complications.
Although GCA is highly treatable, early recognition and prompt treatment are critical. Delay in diagnosis can result in irreversible damage within hours or days.
What Is Giant Cell Arteritis?
Giant cell arteritis is a form of large vessel vasculitis, meaning inflammation of blood vessels.
It primarily affects:
the temporal arteries
arteries supplying the eyes
arteries supplying the brain
the aorta and its major branches
Inflammation causes:
thickening of artery walls
narrowing of the vessel lumen
reduced blood flow to vital tissues
This reduced blood flow is what leads to visual loss, stroke and tissue damage.
Why Is It Called Giant Cell Arteritis or Temporal Arteritis?
The name giant cell arteritis comes from what pathologists see under the microscope when a sample of an affected artery is examined.
In some patients, the inflamed artery wall contains large immune cells called giant cells. These are formed when multiple inflammatory cells fuse together as part of the immune response.
Not every biopsy shows giant cells, but the name has remained because it reflects a typical microscopic feature of the disease.
What Does “Arteritis” Mean?
The word arteritis simply means inflammation of arteries:
artery = a blood vessel that carries blood from the heart
-itis = inflammation
So arteritis = inflammation of an artery.
Why Is It Also Called Temporal Arteritis?
The term temporal arteritis is an older name for GCA. It comes from the fact that the temporal arteries — which run along the sides of the head — are often involved and may become tender, thickened or painful.
However, GCA frequently affects other arteries as well, including:
arteries supplying the eyes
arteries supplying the brain
the aorta and its major branches
For this reason, giant cell arteritis is now the preferred and more accurate term.
Who Gets GCA?
GCA almost exclusively affects people over the age of 50, with peak incidence between 70 and 80 years.
It is more common in women than men
It is more common in people of Northern European ancestry
It is one of the most common forms of vasculitis in older adults
The Link Between GCA and Polymyalgia Rheumatica (PMR)
GCA and polymyalgia rheumatica (PMR) are closely related conditions on the same disease spectrum.
Around 15–20% of people with PMR will develop GCA
Up to 50% of people with GCA have symptoms of PMR
PMR causes:
shoulder and hip pain
morning stiffness
difficulty lifting the arms
difficulty getting out of chairs or bed
Because of this close link, anyone with PMR must be monitored carefully for symptoms of GCA.
What Causes GCA?
The exact cause of GCA is not fully understood.
It is believed to involve:
immune system dysregulation
abnormal activation of inflammatory cells in artery walls
excessive cytokine signalling (including interleukin-6)
genetic susceptibility
possible environmental triggers
This immune-driven inflammation damages the arterial wall and disrupts blood flow.
Common Symptoms of GCA
Symptoms can develop suddenly or over a period of several weeks.
Head and Scalp Symptoms
new-onset headache
scalp tenderness
pain when brushing hair
temple pain
thickened or tender temporal arteries
Jaw Symptoms
jaw pain or fatigue when chewing (jaw claudication)
pain that improves with rest
Jaw claudication is highly specific for GCA.
Visual Symptoms
blurred vision
double vision
visual shadows
partial vision loss
complete sudden blindness
Systemic Symptoms
fatigue
fever
weight loss
night sweats
loss of appetite
Symptoms of Large-Vessel GCA
When the aorta or its major branches are involved:
arm or leg claudication
asymmetric blood pressures
chest or back pain
aortic aneurysm (often silent initially)
Why GCA Is a Medical Emergency
GCA can cause:
permanent vision loss
stroke
aortic aneurysm
aortic dissection
Once vision is lost, it is usually irreversible.
For this reason:
Steroid treatment must be started immediately when GCA is suspected — even before the diagnosis is fully confirmed.
(Related reading: Steroids Explained: Benefits, Risks and How They Are Used Safely in Rheumatology)
How Is GCA Diagnosed?
There is no single perfect diagnostic test.
Diagnosis relies on a combination of:
Clinical Assessment
age over 50
new-onset headache
jaw claudication
scalp tenderness
temporal artery thickening, loss of pulsation
visual symptoms
symptoms of PMR
Blood Tests
Most patients have raised:
ESR
CRP
However:
inflammatory markers can occasionally be normal
normal blood tests do not exclude GCA
(Related reading: Blood Tests in Rheumatology – What Do CRP, ESR and Autoantibodies Really Mean?)
Ophthalmic Assessment
Urgent ophthalmic assessment is essential in anyone with:
visual symptoms
suspected optic nerve involvement
transient visual loss
An ophthalmologist may assess:
visual acuity
visual fields
colour vision
optic disc appearance
retinal circulation
This helps identify:
anterior ischaemic optic neuropathy
retinal artery occlusion
Imaging
Doppler Ultrasound
vessel wall thickening
“halo sign”
PET-CT
aortic inflammation and large-vessel involvement
Temporal Artery Biopsy
Shows:
arterial wall inflammation
sometimes giant cells
Biopsies may be falsely negative.
Treatment should never be delayed.
Treatment of GCA
Immediate Steroid Therapy
prednisolone 40–60 mg daily
IV steroids for visual symptoms
(Related reading: Steroids Explained)
Steroid Tapering
12–24 months
slow reduction
relapses common
Steroid-Sparing Treatment: Tocilizumab
Tocilizumab is a biologic medication that blocks interleukin-6.
It:
reduces relapse
allows faster tapering
reduces steroid toxicity
Tocilizumab is usually prescribed through specialist GCA centres such as the Royal Free Hospital.
Monitoring and Long-Term Risks
relapse
steroid toxicity
infection
osteoporosis
diabetes
hypertension
aortic aneurysm
(Related reading: DEXA Scans Explained and Osteoporosis Explained)
Why Early Specialist Care Matters
urgent diagnosis
immediate steroids
safe tapering
biologic access
complication monitoring
In Summary
GCA is a medical emergency
“arteritis” means inflammation of arteries
“giant cells” are inflammatory cells seen on biopsy
Immediate steroids prevent blindness
Ophthalmic assessment is crucial
Imaging and biopsy support diagnosis
Tocilizumab reduces steroid exposure
Long-term monitoring is essential
Trusted Patient Information Resources
NHS — Giant cell arteritis
Arthritis UK — Giant cell arteritis
Vasculitis UK — Giant cell arteritis
https://www.vasculitis.org.uk/about-vasculitis/giant-cell-arteritis
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.
If you are concerned that you or a relative has GCA, please seek emergency medical attention through A&E or your GP for assessment.