What is the recommended treatment and diagnosis approach for temporal arteritis, specifically giant cell arteritis?

Diagnosis and Treatment of Temporal Arteritis (Giant Cell Arteritis)

Immediate high-dose glucocorticoid therapy should be initiated as soon as GCA is clinically suspected, without waiting for biopsy results, to prevent irreversible vision loss. 1

Diagnostic Approach

Initial Evaluation

• Laboratory Tests:
  • Order immediate ESR and CRP (elevated in >95% of cases)
  • ESR typically >50 mm/h
  • CRP is more sensitive than ESR for acute inflammation
  • Check for normocytic normochromic anemia (sensitivity 87.4%)

Diagnostic Criteria

• American College of Rheumatology criteria (requires 3 of 5):
  1. Age ≥50 years at disease onset
  2. New-onset headache or change in headache pattern
  3. Temporal artery abnormalities (tenderness, reduced pulse)
  4. Elevated ESR (≥50 mm/h)
  5. Abnormal temporal artery biopsy

Confirmatory Testing

• Temporal Artery Biopsy (gold standard):

  • Schedule within 1-2 weeks of starting glucocorticoids
  • Specimen length should be ≥1 cm
  • Unilateral biopsy is usually sufficient
  • Biopsy remains reliable for up to 7-10 days after starting steroids 2
  • Biopsy positivity decreases significantly after 7 days of steroid treatment 3

• Imaging Options:

  • Ultrasound with "halo" sign (88% sensitivity, 97% specificity)
  • Doppler ultrasound of temporal arteries (77% sensitivity, 96% specificity)
  • MRI/CT angiography for large vessel involvement
  • PET-CT with 18F-FDG for detecting large vessel vasculitis

Treatment Protocol

Initial Treatment

• For Uncomplicated GCA:

  • Prednisone 40-60 mg/day orally 1

• For GCA with Visual Symptoms (neuro-ophthalmic emergency):

  • IV methylprednisolone 500-1000 mg/day for 3 days 1, 4
  • Then transition to oral prednisone 80 mg/day (or 1 mg/kg) 4

Maintenance and Tapering

• Maintain high-dose glucocorticoids for one month
• Then begin gradual tapering:
  • Reduce by approximately 10 mg/day every month 4
  • Avoid alternate-day dosing (increases relapse risk)
  • Monitor ESR and CRP during tapering
  • Most patients require approximately 1 year of therapy 4
  • Some may require up to 6 years of treatment 5

Adjunctive Therapy

• Tocilizumab (FDA-approved for GCA):
  • 162 mg subcutaneously weekly 1, 6
  • Reduces glucocorticoid requirements
  • Prevents relapses
  • Particularly valuable for disease relapse with cranial ischemic symptoms

Prevention of Glucocorticoid-Induced Side Effects

• Bone Protection:
  • Calcium and vitamin D supplementation
  • Bisphosphonates for osteoporosis prevention
• Monitoring:
  • Regular blood pressure checks
  • Blood glucose monitoring
  • Consider peptic ulcer prophylaxis

Special Considerations

Visual Symptoms

• Visual loss occurs in approximately 18% of patients at diagnosis
• Usually irreversible once established
• Delayed treatment can result in permanent vision loss in 15-35% of untreated patients
• Visual symptoms may be preceded by amaurosis fugax (temporary vision loss) 2

Disease Relapse

• For relapse with cranial ischemic symptoms:
  • Add tocilizumab (preferred) or other immunosuppressive agent
  • Increase glucocorticoid dose

Severe Disease

• For severe GCA with worsening signs of limb/organ ischemia:
  • Escalate immunosuppressive therapy rather than proceeding directly to surgical intervention

Common Pitfalls to Avoid

• Delaying treatment while awaiting biopsy results - this can lead to irreversible vision loss 2
• Discontinuing steroids prematurely - can result in disease recurrence and complications 2
• Performing biopsy too late after starting steroids - biopsy positivity decreases significantly after 7 days of treatment 3
• Missing atypical presentations - maintain high index of suspicion, especially in older patients 7
• Inadequate monitoring during steroid tapering - can miss early signs of relapse