What is the appropriate workup for suspected temporal arteritis?

From the Guidelines

The appropriate workup for suspected temporal arteritis should begin with a thorough clinical evaluation, including a detailed history and physical examination, followed by laboratory tests such as erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP), and temporal artery biopsy remains the gold standard diagnostic test. The clinical evaluation should focus on symptoms like new-onset headache, scalp tenderness, jaw claudication, and visual disturbances. Laboratory tests are essential, particularly ESR and CRP, which are typically markedly elevated 1. Complete blood count often shows normocytic anemia.

Diagnostic Testing

• Temporal artery biopsy should be performed within 1-2 weeks of starting treatment, as it remains positive for 2-6 weeks after steroid initiation 1.
• The biopsy should be at least 1-2 cm in length due to the skip lesions characteristic of the disease 1.
• Color duplex ultrasonography of the temporal arteries is increasingly used as a non-invasive alternative 1.
• If cranial symptoms are absent but large-vessel involvement is suspected, CT angiography, MR angiography, or PET scanning may be appropriate 1.

Treatment

• Treatment should not be delayed while awaiting diagnostic confirmation; high-dose corticosteroids (prednisone 40-60 mg daily) should be initiated immediately if clinical suspicion is high, especially if vision is threatened, as permanent blindness can occur rapidly without treatment 1.
• The use of high-dose steroids should be initiated quickly within the first 24 hours after symptoms onset to reduce the risk of permanent blindness and to increase the chance of visual recovery 1.

Key Considerations

• A suspected diagnosis of large vessel vasculitis should be confirmed by imaging (ultrasound or MRI for temporal or other cranial arteries, ultrasound, CT, positron-emission-tomography (PET)-CT or MRI for the aorta/extracranial arteries) or histology (temporal artery biopsy) 1.
• Every effort should be made to confirm a suspected diagnosis of large vessel vasculitis, and if the clinical probability is high, a provisional diagnosis of GCA may be made, which needs to be confirmed or revised during follow-up 1.

From the Research

Temporal Arteritis Workup

The workup for suspected temporal arteritis includes several key components:

• Erythrocyte sedimentation rate (ESR) test: an elevated ESR is a common finding in temporal arteritis 2, 3, 4, 5
• Temporal artery biopsy: considered the gold standard for diagnosis, although its positivity can be affected by the timing of corticosteroid treatment 2, 6
• Clinical evaluation: including assessment of symptoms such as temporal headache, jaw claudication, scalp tenderness, and visual disturbances 2, 3, 4, 5
• Laboratory tests: including complete blood count, blood chemistry tests, and inflammatory markers such as C-reactive protein (CRP) 3, 5

Diagnostic Criteria

The American College of Rheumatology (ACR) criteria for giant cell arteritis (GCA) can be used to guide the diagnosis of temporal arteritis 5

• The presence of temporal headache, jaw claudication, and abnormal temporal artery exploration are significant predictors of GCA 5
• A normal ESR makes temporal arteritis unlikely, while an elevated ESR increases the likelihood of disease 4

Timing of Temporal Artery Biopsy

The timing of temporal artery biopsy in relation to corticosteroid treatment is important:

• Biopsy should be performed within 2 weeks of initiating corticosteroids to maximize the chances of a positive result 6
• Delaying biopsy beyond 7 days of corticosteroid treatment may decrease the likelihood of a positive result 6