From the Guidelines
Diagnosing temporal arteritis requires a combination of clinical evaluation, laboratory tests, and biopsy confirmation, with temporal artery biopsy being the definitive diagnostic test, as recommended by the 2021 American College of Rheumatology/Vasculitis Foundation guideline 1. To diagnose temporal arteritis, also known as giant cell arteritis, a doctor will first assess symptoms such as new-onset headache, scalp tenderness, jaw claudication, vision changes, fever, fatigue, and weight loss in patients typically over 50 years old.
- Blood tests are essential, particularly erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP), which are usually markedly elevated, as noted in a systematic review and meta-analysis of 68 unique diagnostic cohort studies 1.
- A complete blood count may show anemia. The definitive diagnostic test is a temporal artery biopsy, where a segment of the artery is removed and examined for inflammatory cells and giant cells.
- This should be performed within 1-2 weeks of starting treatment, as recommended by the guideline 1.
- Imaging studies like ultrasound, MRI, or PET scans may support diagnosis by showing arterial wall inflammation, but temporal artery biopsy is preferred over these imaging studies for establishing a diagnosis of GCA, according to the guideline 1. Early diagnosis is critical as temporal arteritis can cause permanent blindness if untreated.
- Treatment should not be delayed while awaiting biopsy results if clinical suspicion is high, as emphasized by the guideline 1. The condition predominantly affects older adults, particularly women, and is related to an abnormal immune response that causes blood vessel inflammation.
- A long-segment temporal artery biopsy specimen (>1 cm) is preferred over a short-segment temporal artery biopsy specimen (<1 cm), as recommended by the guideline 1.
From the Research
Diagnostic Criteria for Temporal Arteritis
The diagnosis of temporal arteritis, also known as giant cell arteritis, is primarily clinical and not solely dependent on a positive temporal artery biopsy (TABx) [ 2 ]. The following criteria are used to diagnose temporal arteritis:
- Clinical suspicion based on symptoms such as polymyalgia rheumatica, new-onset headache, jaw claudication, and visual symptoms like diplopia and amaurosis fugax [ 3 ]
- Laboratory testing, including erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP) [ 3 ]
- Temporal artery biopsy, which is the gold standard for diagnosis but can be negative in some cases [ 2 ]
Clinical Features and Diagnostic Value
Certain clinical features can increase or decrease the likelihood of temporal arteritis:
- Jaw claudication and diplopia substantially increase the likelihood of temporal arteritis [ 4 ]
- Temporal artery beading, prominence, and tenderness are predictive physical findings [ 4 ]
- A normal ESR value indicates a much lower likelihood of disease [ 4 ]
- The absence of any temporal artery abnormality modestly reduces the likelihood of disease [ 4 ]
Importance of Early Diagnosis and Treatment
Early diagnosis and treatment of temporal arteritis are crucial to prevent permanent vision loss and other complications [ 3 ]. Primary care physicians and health practitioners should be aware of the clinical presentation, key investigations, and time-sensitive management of this disease [ 5 ]. A clinical guide to the evaluation of temporal arteritis can assist clinicians in the care of patients with this condition [ 6 ].