Giant cell / Temporal arteritis
STEP1: Calculate GCA Pre-Test Probability
CRP: Use greatest value after onset of symptoms but before steroids started.
Constitutional: One or more of; fever, night sweats, weight loss
PMR: Symptoms of >30 minutes morning stiffness shoulder/hip girdle muscles, or any past use of steroids for PMR diagnosis.
Ischaemic: Acute blurring of vision confined to one eye only, diplopia, amaurosis fugax, jaw/tongue pain when chewing.
Ophthalmology findings: Acute ischaemic optic neuritis, central retinal artery occlusion, visual field defect, relative afferent pupillary defect. This section can be omitted in a primary care setting and scored as 0.
Likely alternative diagnosis or non-white ethnic group: Score yes if non-white, or any of the following are more likely, or as likely, as GCA to account for current symptoms and signs; active infection, active cancer, other rheumatological condition, other head or neck pathology
STEP2: Use total score to guide next management step
STEP3: Use above scoring to navigate referral pathway
Additional Information/Further Reading
(1) For the vast majority of patients the above steroid starting doses should suffice, for those at extremes of BMI (e.g. >100kg or <50kg), a weight based dosing of 0.7mg/kg in place of 60mg prednisolone and 0.5mg/kg in place of 40mg prednisolone can be employed.
(2) Rheumatology on call is from 9am-5pm weekdays. Out of hours, or in the event we are unable to answer immediately voicemails can be left to give details to call back but responsibility to discuss remains with the referrer.
There have been no confirmed cases to date of GCA in patients with PTPS<9
Almost all GCA patients with cranial disease are over 60
GCA is very rare in non-white patients
Only 4% GCA patients have normal CRP and Plasma Viscosity (most of these will have focal ischaemic symptoms)
Once referred to rheumatology we will normally arrange an urgent temporal artery biopsy procedure through vascular surgery or ophthalmology and review in clinic 3-4 weeks later. Some cases may be discharged back to GP at this point if we feel GCA has been ruled out.
If GCA is diagnosed/not ruled out then we will normally follow the steroid reduction regime as detailed below and consider if long term bone protection is necessary.
In cases who relapse during prednisolone reduction, particularly if >10mg prednisolone, we will consider adding steroid sparing agents such as methotrexate or leflunomide to augment the next attempt at steroid dose reduction. In severe cases a biologic agent called ‘Tocilizumab’ is sometimes used (pending regional approval.)
In patients with significant steroid toxicity a faster steroid reduction regime and earlier use of steroid sparing agents may be required.
If headache or PMR symptoms recur on dose reduction, then return to previously effective dose of prednisolone and inform rheumatology.
If ischaemic symptoms develop (either new or recurrent) then commence high dose prednisolone and manage as per a new case.
Versus Arthritis, GCA patient information.
Mackie S, Dejaco S, Appenzeller Set al. British Society for Rheumatology guideline on diagnosis and treatment of giant cell arteritis, Rheumatology, Volume 59, Issue 3, March 2020, Pages e1–e23, https://doi.org/10.1093/rheumatology/kez672
Sebastian A, Tomelleri A, Kayani A, et al. Probability-based algorithm using ultrasound and additional tests for suspected GCA in a fast-track clinic. RMD Open. 2020 Sep;6(3):e001297. doi: 10.1136/rmdopen-2020-001297
Quick V, Hughes M, Mothojakan N, Fishman D. P180 External validation of the Southend GCA Probability Score (GCAPS) as a screening tool for referrals with possible GCA, Rheumatology, Volume 59, Issue Supplement_2, April 2020, keaa111.175, https://doi.org/10.1093/rheumatology/keaa111.175
Dr Laura McArthur, GPST3
Dr Mark Hughes, Consultant Rheumatologist, RCHT
Dr Bridgitte Wesson, GP & Kernow RMS Rheumatology guideline lead
Guidelines reviewed: September 2021
Next review due: September 2022