What is the work‑up for suspected giant‑cell arteritis in a patient over 50?

Temporal Arteritis Work-Up

Immediate Clinical Assessment

In any patient over 50 years old with suspected giant cell arteritis (GCA), immediately obtain ESR, CRP, and complete blood count, then start high-dose corticosteroids without waiting for biopsy confirmation. 1, 2

Key Clinical Features to Assess

• New-onset headache is present in two-thirds of patients and up to 90% of biopsy-confirmed cases—this is the most common presenting symptom 2
• Jaw claudication (pain with chewing that resolves with rest) is the most specific symptom with a positive likelihood ratio of 4.90, occurring in approximately 50% of patients 2
• Visual disturbances including transient vision loss (amaurosis fugax), diplopia, or blurred vision occur in 20% of patients before permanent blindness develops 2
• Scalp tenderness has a positive likelihood ratio of 3.14 and is highly suggestive when present 2
• Temporal artery abnormalities on palpation—look for thickening (LR+ 4.70), loss of pulse (LR+ 3.25), or tenderness 2
• Constitutional symptoms including weight loss, low-grade fever, fatigue, and night sweats support the diagnosis 1

Laboratory Work-Up

• ESR and CRP are elevated in more than 95% of cases at diagnosis—ESR >100 mm/h has a positive likelihood ratio of 3.11 2
• Normal ESR (<40 mm/h) or normal CRP (<2.5 mg/dL) make GCA unlikely, with negative likelihood ratios of 0.18 and 0.38 respectively, and should prompt consideration of alternative diagnoses 3, 2
• Platelet count >400 × 10³/μL has a positive likelihood ratio of 3.75 and supports the diagnosis 2
• Complete blood count and comprehensive metabolic panel provide additional diagnostic information 1

Diagnostic Confirmation

Temporal Artery Biopsy

• Arrange temporal artery biopsy within 2 weeks of starting corticosteroids—this remains the gold standard for diagnosis 3, 1
• Obtain a long-segment biopsy (≥1 cm) to improve diagnostic yield, as skip lesions can cause false negatives 3, 2
• Do not delay treatment while awaiting biopsy, as histopathological findings remain detectable for 1-2 weeks after starting steroids 3
• Contralateral biopsy is not routinely indicated unless the first biopsy is negative and clinical suspicion remains high 3

Vascular Imaging

• If temporal artery biopsy is negative but clinical suspicion remains high, obtain noninvasive vascular imaging (MRI or CT angiography) of the thoracic aorta and branch vessels to evaluate for large vessel involvement 1
• Temporal artery ultrasound showing the "halo sign" (circumferential wall thickening) has 88% sensitivity and 97% specificity when performed by experienced operators 3, 1
• Baseline imaging of neck/chest/abdomen/pelvis should be obtained to document extent of large vessel involvement 1

Critical Pitfalls to Avoid

• Never delay corticosteroid treatment while awaiting biopsy confirmation—vision loss is often irreversible and can occur rapidly 3, 1
• Consider dental evaluation if ESR is elevated but CRP is normal, as tooth infections can elevate ESR while CRP remains normal, and dental pain can mimic jaw claudication 1
• Do not rely solely on inflammatory markers for diagnosis—clinical assessment takes priority, and isolated elevation of ESR/CRP without symptoms warrants observation rather than treatment escalation 1
• Recognize that without treatment, the risk of vision loss in the second eye approaches 50% if one eye is already affected 1

Initial Treatment Protocol

• For patients without visual symptoms: Start oral prednisone 40-60 mg daily (or 1 mg/kg/day, maximum 60 mg) immediately upon clinical suspicion 1, 2
• For patients with visual symptoms or threatened vision loss: Administer IV methylprednisolone 500-1000 mg daily for 3 consecutive days, then transition to high-dose oral prednisone 3, 1
• Add low-dose aspirin (75-150 mg daily) for all patients to protect against cardiovascular and cerebrovascular events 2