What are the diagnostic criteria and treatment options for temporal arteritis?

Diagnostic Criteria and Treatment Options for Temporal Arteritis

Temporal arteritis requires immediate high-dose glucocorticoid therapy upon clinical suspicion, even before biopsy confirmation, to prevent permanent vision loss. 1

Diagnostic Criteria

Clinical Presentation

• New-onset persistent localized headache, often in the temporal area, with scalp tenderness and constitutional symptoms 1
• Jaw claudication is highly specific with a positive likelihood ratio (LR) of 4.90 2, 1
• Limb claudication has a positive LR of 6.01, making it the most specific clinical feature 2
• Temporal artery abnormalities including:
  • Temporal artery thickening (positive LR 4.70) 2
  • Loss of pulse (positive LR 3.25) 2
  • Temporal tenderness (positive LR 3.14) 2, 1

Laboratory Findings

• Elevated inflammatory markers are crucial for diagnosis:
  • ESR >100 mm/h has a positive LR of 3.11 2, 3
  • Absence of ESR >40 mm/h has a negative LR of 0.18, making it an excellent screening tool 2, 3
  • CRP ≥2.5 mg/dL is important (absence has negative LR of 0.38) 2, 1
  • Platelet count >400 × 10³/μL has a positive LR of 3.75 2, 1

Diagnostic Confirmation

• Temporal artery biopsy with specimen length >1 cm is the gold standard for diagnosis 1, 4
• Biopsy should be performed within 2 weeks of starting treatment 4
• Vascular imaging (ultrasound, MRI, PET, CT) can identify large vessel involvement and may be useful when biopsy is negative but clinical suspicion remains high 1, 4

Treatment Options

Initial Management

• Start high-dose glucocorticoids immediately upon clinical suspicion:
  • Oral prednisone 1 mg/kg/day (maximum 60 mg/day) for patients without visual symptoms 1, 4
  • Intravenous pulse methylprednisolone (500-1000 mg/day for 3 days) for patients with threatened vision loss, followed by high-dose oral prednisone 4

Glucocorticoid Tapering

• Begin gradual taper after 1 month of high-dose therapy 4
• Target dose of 10-15 mg/day by 3 months 4
• Aim for ≤5 mg/day after 1 year 1, 4
• Guide tapering by clinical symptoms and normalization of inflammatory markers 4

Steroid-Sparing Agents

• Tocilizumab is recommended as first-line adjunctive therapy with glucocorticoids, especially for patients at high risk of steroid-related complications 1, 4
• Methotrexate can be considered as an alternative if tocilizumab is contraindicated 4

Management of Relapses

• For disease relapse with cranial ischemic symptoms:
  • Add a non-glucocorticoid immunosuppressive agent (preferably tocilizumab) 4
  • Increase glucocorticoid dose 4

Monitoring

• Regular assessment for clinical signs and symptoms of active disease 1, 4
• Monitor inflammatory markers (ESR, CRP) 1, 4
• Assess for glucocorticoid-related adverse effects and provide appropriate prophylaxis 4

Clinical Pitfalls and Caveats

• No single clinical or laboratory feature is sufficient to rule in or rule out the disease; combinations of features should guide clinical suspicion 2, 1
• Fast-track referral within 24 hours is recommended to reduce the risk of permanent visual impairment 1
• Without treatment, the risk of vision loss in the second eye is as high as 50% if one eye is already affected 4
• Visual loss occurs in 15-35% of patients, primarily before initiation of therapy 4
• Glucocorticoid-related adverse events are common (86% of patients) with long-term therapy 4
• Normal inflammatory markers should raise suspicion for alternative diagnoses 3