In Japan, giant Cell Arteritis is managed by rheumatologists. Giant cell arteritis is a large- and medium-vessel vasculitis affecting adults aged 50 and older, characterized by granulomatous inflammation of the aorta and its major branches, particularly the extracranial branches of the external carotid artery. Annual incidence is roughly 17-29 per 100,000 in Scandinavian populations aged 50 and older and lower in southern Europe, Asia, and Africa, with female-to-male ratio approximately 3:1.
Giant cell arteritis (GCA, ICD-10: M31.5 GCA without polymyalgia rheumatica, M31.6 GCA with polymyalgia rheumatica, M31.7 anterior ischemic optic neuropathy associated) is a chronic granulomatous large- and medium-vessel vasculitis of adults aged 50 and older. The 2012 Chapel Hill Consensus Conference and 2022 ACR/EULAR classification criteria describe two overlapping phenotypes: cranial GCA, with predominant involvement of the extracranial branches of the external carotid artery (especially the superficial temporal, occipital, and posterior ciliary arteries), and large-vessel GCA, which involves the aorta and its major branches with axillary, subclavian, and aortic involvement detectable by imaging in 30-80% of patients. Polymyalgia rheumatica is a closely related condition affecting proximal muscle groups, with shared epidemiology and overlap in 40-60% of GCA patients. The pathological hallmark is transmural inflammation with mononuclear infiltrate, fragmentation of the internal elastic lamina, and granulomas often containing multinucleated giant cells.
The key symptoms of Giant Cell Arteritis are: New-onset, persistent headache, often unilateral and located over the temporal region, sometimes described as throbbing or boring; present in 70-80% of patients at diagnosis., Scalp tenderness — discomfort when combing hair or wearing glasses — reflecting inflammation of branches of the external carotid artery., Jaw claudication: pain or fatigue in the masseter muscle while chewing, relieved by rest. The most specific symptom for GCA, present in approximately 30-50% of cases., Visual symptoms: amaurosis fugax (transient monocular vision loss lasting seconds to minutes), diplopia, partial or complete vision loss, often described as 'a curtain coming down' over the eye., Anterior ischemic optic neuropathy producing sudden permanent unilateral blindness or severe visual loss; occurs in 15-20% of untreated cases., Polymyalgic shoulder and hip-girdle pain with morning stiffness lasting more than 30 minutes, present in 40-60% of patients., Constitutional symptoms: low-grade fever, fatigue, malaise, anorexia, and unexplained weight loss of 5-10% over weeks to months..
Diagnosis combines clinical features, inflammatory markers, imaging, and biopsy according to the 2022 ACR/EULAR classification criteria. The clinical assessment focuses on the symptoms and signs of cranial and large-vessel disease, polymyalgic features, and constitutional symptoms. Laboratory testing nearly always shows elevated ESR (typically >50 mm/h, often 80-100+) and CRP (often >25 mg/L), with normocytic anemia, mild thrombocytosis, and modest liver enzyme elevation. ESR and CRP are normal in fewer than 5% of cases. The American College of Rheumatology and EULAR recommend imaging-first diagnostic strategies where expertise is available: temporal artery ultrasound demonstrating a non-compressible 'halo' sign (hypoechoic vessel wall thickening) is highly specific and increasingly used as a first-line confirmatory test. MR angiography of head, neck, and chest and FDG-PET-CT identify large-vessel involvement. Temporal artery biopsy remains the gold standard when imaging is unavailable or inconclusive, ideally performed within 14 days of starting corticosteroids and on a 1-2 cm segment of the symptomatic side. False negatives occur because of skip lesions; contralateral biopsy may be considered in suspicious cases with a negative first biopsy. The 2022 ACR/EULAR criteria require age ≥50, biopsy or imaging showing GCA, and the presence of additional clinical, laboratory, or imaging features summing to ≥6 points. Once diagnosis is made, baseline imaging from neck through chest is increasingly recommended to map large-vessel involvement and guide surveillance for aortic aneurysm, which develops in up to 18% of patients over 10 years.
GCA mortality is generally similar to the age-matched general population when properly treated, but cardiovascular and cerebrovascular events are increased and aortic aneurysm and dissection are leading late causes of disease-related death. Visual loss occurs in 15-20% of untreated patients and falls to under 5% with prompt high-dose corticosteroid therapy; recovery of established vision loss is rare. Relapse occurs in 50-70% of patients during corticosteroid taper without steroid-sparing therapy and approximately 40% with tocilizumab co-therapy. Cumulative glucocorticoid-related morbidity (osteoporosis with fractures, infections, diabetes, hypertension, cataracts, weight gain, mood changes) is substantial and is the dominant long-term issue when GCA itself is controlled. Approximately 70% of patients ultimately achieve sustained remission off corticosteroids. Tocilizumab and other steroid-sparing strategies are extending steroid-free remission rates and reducing cumulative steroid exposure. Aortic aneurysm develops in up to 18% over 10 years; structured surveillance with annual imaging improves detection.
Rheumatologists with experience in vasculitis diagnose and manage GCA, individualize corticosteroid tapering, supervise steroid-sparing biologics, and surveil for large-vessel complications. Ophthalmology involvement is essential for any visual symptoms. Vascular surgery and cardiology contribute when aortic or limb arterial involvement is significant.
Find specialists →Symptomatic improvement (headache, jaw pain, polymyalgia) within 24-72 hours of starting corticosteroids; inflammatory markers normalize over 2-6 weeks. Induction dose for 2-4 weeks; tapered to 10-20 mg by 3 months, 7.5-10 mg by 6 months, 5 mg or off by 12-24 months. Tocilizumab continues for 12-24 months in most protocols. Aortic surveillance imaging recommended annually for at least 5 years.
Maintain regular weight-bearing exercise (walking, light resistance training, balance exercises) throughout treatment. Avoid high-impact activities during prolonged high-dose corticosteroid therapy because of fracture risk. Physical therapy referral is reasonable for patients with polymyalgic shoulder and hip-girdle pain and for fall-prevention training.
Choose a rheumatologist with vasculitis experience at a center with temporal artery ultrasound, biopsy capability, MR or CT angiography, and access to tocilizumab. For visual symptoms, prefer immediate ophthalmology evaluation alongside rheumatology. Academic vasculitis centers offer trials and complex care for refractory disease.
Medically reviewed by AIHealz Medical Editorial Board · May 13, 2026
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