Giant Cell Arteritis - Temporal Arteritis

Diagnosis

Indications for Testing

• Patient >50 years with visual changes or new onset headache

Criteria for Diagnosis

• American College of Rheumatology (1990); 3 of 5 required
  • Age – >50 years
  • New localized headache
  • Temporal artery tenderness or decreased pulsation
  • ESR – >50 mm/hr
  • Abnormal arterial artery biopsy

Laboratory Testing

• Nonspecific testing
  • CBC –  may have platelet count >375,000 (L.R. 6.0); normochromic normocytic anemia
  • ESR/CRP – elevated; if both are elevated, sensitivity of diagnosis increased to 99%
    • ESR usually exceeds 50 mm/hr and may exceed 100 mm/hr (L.R. 2.5)
  • Liver function studies – often abnormal
•  Testing for vasculitis
  • ANCA – 75% have pANCA with MPO+
    • PR3 rarely positive

Histology

• Temporal artery biopsy – medium- and large-vessel vasculitis with giant cell infiltration
  • May have skin lesions; therefore, 2 cm long biopsy is recommended
• Biopsy should be performed before day 4 of steroid therapy
• If initial biopsy is negative, perform biopsy on other side

Imaging Studies

• Duplex ultrasonography
  • Halo sign is often present – defined as hypoechoic region around the lumen of the artery
  • Sensitivity <70%

Differential Diagnosis 

• Infectious
  • Viral infections
  • Endocarditis
  • Hepatitis A, B, C
  • HIV
• Malignancy
• Multiple myeloma
• Connective tissue
  • Systemic lupus erythematosus
  • Rheumatoid arthritis
  • Polymyositis
• Fibromyalgia
• Myalgias from statin therapy
• Osteoarthritis
• Other vasculitis
  • Wegener granulomatosis
  • Churg-Strauss syndrome
  • Microscopic polyangiitis
  • Polyarteritis nodosa

Clinical Background

Giant cell arteritis, also known as temporal arteritis, is a systemic vasculitis that can produce permanent blindness if not treated in a timely manner.

Epidemiology

• Incidence – 18-22/1,000,000 in U.S.; most common primary vasculitis in older patients
• Age – almost exclusively >50 years; peak age 70-80 years
• Sex – M<F, 1:2-6
• Ethnicity – more common in Caucasians than African Americans; rare in Hispanic population

Pathophysiology

• Medium- and large-vessel vasculitis – tends to affect aorta and extracranial branches of the carotid artery
• Causes ischemic disease – most common in the optic nerve
  • Can lead to vision loss, caused primarily by occlusive vasculopathy
• Granulomas form in arterial media
• Often associated with polymyalgia rheumatica

Clinical Presentation

• Constitutional – fever, fatigue, malaise, weight loss
• Otorhinologic – jaw claudication (L.R. 4.0)
• Ophthalmologic – transient visual changes, diplopia (L.R. 3.4), visual field cuts, permanent vision loss
• Cardiovascular – arm claudication, thoracic artery aneurysm
• Neurologic – headache, temporal artery pain (L.R. 2.0), mononeuropathy
• Polymyalgia rheumatica – symptoms occur in up to 50% of patients
  • Manifests with severe stiffness and pain in shoulders, thighs, and buttocks

Treatment

• Steroids – first-line therapy
• May require addition of other immunosuppressives in order to taper steroids

Indications for Laboratory Testing

• Tests generally appear in the order most useful for common clinical situations
• Click on number for test-specific information in the ARUP Laboratory Test Directory