Giant Cell Arteritis
Introduction
Giant cell arteritis is a chronic systemic vasculitis involving medium and large arteries. It is a disease of older adults with the greatest incidence occurring in patients older than 70 and is almost never seen in people under 50 (1). Cranial branches of the carotid artery are commonly affected. Due to the superficial location of the superficial temporal artery it is the most common site for vascular biopsy to confirm the diagnosis (2). This is probably why it is often referred to as temporal arteritis. If left untreated over one third of patients experience permanent visual loss, hence the importance of timely recognition, diagnosis and management.
Clinical Features
Risk Factors
Age
Northern European ancestry
Female gender (F:M = 3:1)
Family history
Polymyalgia rheumatica (PMR)
Signs
Clinical examination may be completely normal however the presence of the following findings increases the chances of having a positive temporal artery biopsy.
Tenderness over the temporal arteries (+ve LR 2.6)
Loss of pulsation of the temporal artery (+ve LR 2.7)
Prominent / enlarged temporal artery (+ve LR4.3)
Other large and medium size arteries other than the cranial arteries can be affected leading to the below findings
Aortic regurgitation – suggests development of aortic artery aneurysm and significant aortitis
Abnormal pulses
Symptoms
Headache (80%)
New headache
Often unilateral but can be sometimes be generalized
Can be progressively worsening, waxing and waning or constant
Jaw claudication (50% of patients)
Fatigue
Fever
Weight loss
Night sweats
Diplopia
Amaurosis fugax
Complications
Permanent vision loss
Can be unilateral or bilateral
May be preceded by transient visual loss
Once established is rarely reversible and the second unaffected eye often is involved within a week of initial visual loss
High dose glucocorticoids almost completely remove the risk of visual loss while vision is still in tact
Other complications
Dependent on what other vessels are involved
Differential Diagnosis
Headache
Primary headache disorder
Tension / migraine
Symptomatic severe hypertension
Intracranial bleed
Acute angle closure glaucoma
Space occupying lesion
Meningitis / encephalitis
Eye Symptoms
Stroke / TIA
Ischaemic optic neuropathies
Clinical Investigations
Bedside & Laboratory
BM – should check baseline in case steroids treatment is required. Steroids can cause significant changes in blood sugar
ESR
usually but not always significantly raised, one study found 5% of patients with biopsy proven GCA had an ESR of less than 40 (3)
FBC / U&E / Coag useful in the management of other differentials
Other
Temporal artery biopsy is the gold standard diagnostic test
Initially a unilateral temporal artery biopsy is performed
Due to ‘skip lesions’ a negative biopsy does not rule out the diagnosis if there is a very high clinical suspicion
If clinical suspicion is very high and initial biopsy is negative a contralateral biopsy may be performed
Radiologic
Colour doppler ultrasound (CDUS) has been proposed as an alternative to the traditional temporal artery biopsy
Studies have shown consistently high specificity when compared with temporal artery biopsy however the sensitivities have been widely variable (4)
This would suggest that CDUS may be a useful rule in test however due to inter-operator variability is unlikely to be useful in ruling out the diagnosis of GCA
If other large vessel involvement is suspected (for example the aortic arch) then CT angiography is necessary
Central CT or MR imaging is not useful in diagnosing GCA however, depending on the clinical situation may be required to rule out other differentials
Treatment & Disposition
Symptomatic treatment
Simple analgesia can be given for headache symptoms
Paracetamol 1g po
Ibuprofen 400mg po
Specific Treatment
High dose steroids – prednisolone 1mg/kg to a max of 60mg
They should be started as soon as the diagnosis is strongly suspected but most importantly should not be delayed in patients with threatened or recent vision loss
While high dose steroids can have significant side effects particularly in older adults if the diagnosis is highly suspected they should be initiated immediately while awaiting confirmatory temporal artery biopsy
Histopathologic evidence of GCA will be present for at least a month after starting steroid treatment
In patients with severe adverse reactions to steroids alternative agents such as methotrexate or tocilizumab may be used (5)
Disposition
If timely follow-up with temporal artery biopsy to confirm the diagnosis can be confirmed patients can be discharged on high dose prednisolone
If timely follow-up cannot be arranged or life-threatening differentials cannot be ruled out patients may require admission for diagnostic work up
References
Mann CJ. RCEM Learning; Secondary Headahce. [Online].; 2015 [cited 2020 October. Available from: https://www.rcemlearning.co.uk/modules/secondary-headache/.
Docken WP, Rosenbaum JT. Clinical manifestations of giant cell arteritis. In UptoDate.: https://www.uptodate.com/contents/clinical-manifestations-of-giant-cell-arteritis?search=temporal%20arteritis&source=search_result&selectedTitle=3~133&usage_type=default&display_rank=3; 2019.
Salvarani C, Hunder GG. Giant cell arteritis with low erythrocyte sedimentation rate: frequency of occurence in a population-based study. Arthritis & Rheumatology. 2001 April; 45(2).
Arida A, Kyprianou M, Kanakis M, Sfikakis PP. The diagnostic value of ultrasonography-derived oedema of the temporal artery wall in giant cell arteritis: a second meta-analysis. BMC Musculoskeletal Disorders. 2010 March; 11(44).
Docken WP, Trobe J, Matteson EL, Curtis MR. Treatment of giant cell arteritis. [Online].; 2020 [cited 2021 February 13. Available from: https://www.uptodate.com/contents/treatment-of-giant-cell-arteritis?search=giant%20cell%20arteritis&source=search_result&selectedTitle=2~138&usage_type=default&display_rank=2#H4271942575.
This blog was written by Dr. Emer Kidney and was last updated in February 2021