- Low probability → consider alternative diagnoses.
- Medium probability → do ultrasound first and biopsy if unclear.
- High probability → positive ultrasound alone can confirm diagnosis, though biopsy may still be done for confirmation.
Giant Cell Arteritis (GCA)
NICE CKS Giant cell arteritis. Last revised: Jul 2024.
British Society for Rheumatology guideline on diagnosis and treatment of giant cell arteritis. Published: Jan 2020.
Background Information
Clinical Features
Suspect GCA if >50 y/o with at least one of the following:
- New-onset headache (usually temporal but may be more generalised, occipital or parietal) – most common symptoms
- Temporal artery abnormality
- Tenderness / thickening / nodularity (present up to 30%)
- Red overlying skin
- Reduced / absent pulsation
Other suggestive features:
- Visual disturbances – loss of vision / diplopia / change to colour vision
- Scalp tenderness
- Intermittent jaw claudication
- Neurological features
- Mononeuropathy / polyneuropathy
- Upper cranial nerve palsies
- TIA / stroke (less common)
- Systemic features – fatigue, fever, anorexia, weight loss, depression
- PMR features seen in ~40% (e.g. proximal muscle pain, stiffness, and tenderness)
None of the GCA signs or symptoms is pathognomic, they are all very non-specific.
Guidelines
Investigation and Diagnosis
Diagnostic Tests
Bloods to be taken before or immediately after starting steroids
- FBC, CRP, ESR (raised ESR supports the diagnosis)
Diagnostic tests:
- Initial: temporal artery ultrasound
- Halo sign (hypoechoic thickening around vessels) – suggests vessel wall inflammation
- Compression sign (non-compressible artery)
- Stenosis & occlusion
- Definitive: temporal artery biopsy
- -ve biopsy does not exclude diagnosis if there is strong clinical suspicion and supportive investigations
- Segmental/skip lesions can produce false-negatives
The results of these tests should NEVER delay the initiation of glucocorticoid therapy if the disease is strongly suspected!
Extra (beyond expected knowledge for medical school exams): The British Society of Rheumatology suggests tailoring the diagnostic approach based on the pretest probability (based on clinical suspicion) of GCA.
Other Tests
Other investigations to exclude alternative diagnoses or identify increased risk of glucocorticoid-related adverse effects:
- Baseline U&E, HbA1c, calcium, LFT
- Screening tests for risk of serious infection (e.g. urine dipstick, chest X-ray, latent tuberculosis screening)
- Screening test for osteoporosis risk (e.g. TSH, vitamin D, bone density test, DEXA)
Management
Initial Management
Management is guided by whether there are visual changes or not.
YES Visual Changes
Visual changes include: new visual loss (transient or permanent) OR double vision
Urgent same-day referral to ophthalmology
- 1st line: IV methylprednisolone 0.5-1g up to 3 consecutive days before commencing oral prednisolone
- Alternative: oral prednisolone 60-100mg per day
NO Visual Changes
Refer all suspected GCA cases to a specialist (ASAP but within 3 days):
- Do not delay referral while ordering and waiting for results in primary care
If GCA is strongly suspected, treatment can be started immediately:
1st line: oral prednisolone 40-60 mg per day
- Most patients respond clinically within 1 week
- Failure to respond should prompt re-evaluation of diagnosis
Steroids should be started without awaiting laboratory results / confirmatory diagnotic tests if GCA is strongly suspected clinically.
Ongoing Management
Maintain the initial steroid dose until symptoms and inflammatory markers (CRP, ESR) resolve
- Once in remission, steroid dose should be tapered to zero over 12–18 months, provided there is no return of GCA symptoms, signs or laboratory markers of inflammation
- Some patients may require low doses of corticosteroids for several further years
For those at high risk of steroid toxicity or relapse while tapering, consider adding the following with the steroid tapering:
- Methotrexate, or
- Tocilizumab (strong recommendation)
References