Classic Features of Temporal Arteritis (Giant Cell Arteritis)
The classic clinical features of temporal arteritis include new-onset headache, temporal artery abnormalities (thickening, tenderness, or loss of pulse), jaw claudication, visual symptoms (particularly sudden vision loss or amaurosis fugax), and markedly elevated inflammatory markers (ESR >50 mm/hr or CRP >10 mg/L), typically occurring in patients over 50 years of age. 1, 2, 3
Cranial Manifestations
The most characteristic cranial features include:
New-onset headache - Present in the majority of patients, though it has limited diagnostic specificity as it occurs commonly in both GCA-positive and negative patients 2
Temporal artery abnormalities - These are highly specific findings:
Jaw claudication - A highly characteristic feature that significantly increases diagnostic probability 2, 4
Scalp tenderness - Another statistically significant clinical feature 4
Visual Manifestations
Visual symptoms represent the most feared complications and include:
- Sudden vision loss - Carries significant diagnostic weight (+3 points in classification criteria) 3
- Amaurosis fugax (transient vision loss) - A warning sign of impending permanent vision loss 5, 6
- Anterior ischemic optic neuropathy (AION) - Sensitivity 24%, specificity 89% 2
- Diplopia - Results from ischemia of ocular muscles 5, 7
- Optic nerve pallor - A statistically significant finding in biopsy-proven cases 4
Systemic and Constitutional Features
- Polymyalgia rheumatica (PMR) - Present in approximately 33% of cases, with positive LR of 1.45 2
- Constitutional symptoms including:
Large Vessel Involvement
Extracranial manifestations include:
- Limb claudication - Highly specific (specificity 97%) with positive LR of 7.23, though less sensitive (20%) 2
- Absent pulses 1
- Blood pressure inequality between limbs 6
- Bilateral axillary involvement on imaging 3
Laboratory Findings
- Markedly elevated ESR - ESR >50 mm/hr has sensitivity of 79% and is weighted +3 points in classification criteria 2, 3
- Elevated CRP (>10 mg/L) - Sensitivity 79%, specificity 54%, weighted +3 points 2, 3
- Anemia - Present in 87% of cases but with low specificity (31%) 2
Critical Clinical Caveats
Important pitfall: Classic symptoms like headache, scalp tenderness, and constitutional symptoms have limited diagnostic specificity because they occur frequently in both GCA-positive and negative patients 2. Their high prevalence should not be mistaken for high diagnostic value.
Age requirement: Patients must be ≥50 years old, as this is an absolute requirement for classification 3. The disease peaks in the seventh decade 9.
Seronegative disease exists: Normal ESR and CRP do not exclude the diagnosis in patients with classic clinical features 9. The diagnosis remains fundamentally clinical 9.
Temporal artery biopsy: While showing transmural inflammation is the gold standard, a negative biopsy does not rule out GCA 4, 9. Only 23% of biopsies may be positive even in suspected cases 4.
The 2022 ACR/EULAR classification criteria require a cumulative score of ≥6 points from weighted clinical features, with positive temporal artery biopsy or halo sign on ultrasound carrying the highest weight (+5 points), followed by inflammatory markers and sudden visual loss (+3 points each) 3.