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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