Giant Cell Arteritis (Temporal Arteritis, Horton Disease, Cranial Arteritis)

Epidemiology

  • Sex: F>M ratio is 3 to 1
  • Peak age: >55 y/o (mean age on onset: 72 y/o)
  • Prevalence: 150-350 cases per million persons over age 50
  • More common in patients of Northern European descent
  • Associated with: polymyalgia rheumatica (50% of cases)

Physiology

  • arteritis of medium and large-sized arteries

Arterial Involvement:
a) Carotid artery
b) Carotid branches
c) Opthlamic or posterior ciliary arteries: involvement may cause anterior ischemic optic neuropathy


Diagnosis

  • CBC: anemia (normochromic/ normocytic)
  • LFT’s: elevated alkaline phosphatase
  • ABG: elevated A-a gradient
  • ESR: elevated (<50 in only 10% of cases)
  • Immune complexes: positive
  • PFT’s: decreased DLCO/elevated Vd/Vt ratio
  • Temporal artery Doppler U/S: may be useful, but does not substitute for bx
  • Angiogram: may be useful
  • Temporal artery Bx (or other cranial arteries at autopsy): diagnostic (lymphocytic and giant cell infiltrate/ destruction of elastic membranes)
    • Negative biopsy specimen of >1 cm rules out diagnosis with 90% certainty

Clinical

Ocular Involvement

  • Headache
  • Temporal artery tenderness
  • Visual symptoms: amaurosis fugax, diplopia
  • Blindness (15% of cases): usually irreversible/rarely occurs after treatment has started

Pulmonary Involvement

  • Pulmonary HTN: PA may sometimes be involved
  • ILD: few case reports
  • Lung Nodules: few reported cases

Neuro Involvement

  • Vertigo
  • Dementia: may occur acutely
  • CVA

Rheum Involvement

  • Arthralgias

Cardiovascular Involvement

  • Aorta: may sometimes be involved
  • MI

Constitutional

  • Myalgias
  • Fever
  • Jaw claudication

Treatment

  • Corticosteroids: useful
  • May need to start therapy prior to temporal artery bx
  • Data regarding methotrexate as a steroid-sparing agent are equivocal

References

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