Top Causes of Arteritic Ischemic Optic Neuropathy
Giant cell arteritis (GCA) is overwhelmingly the predominant cause of arteritic anterior ischemic optic neuropathy (A-AION), accounting for the vast majority of cases, with other vasculitides being exceedingly rare. 1, 2, 3
Primary Cause
1. Giant Cell Arteritis (Temporal Arteritis)
- This is the cause in nearly all cases of arteritic AION, particularly in Caucasians over age 50 1, 2
- Clinical indicators include temporal tenderness, jaw claudication, weight loss, proximal myalgia (polymyalgia rheumatica), and fever 1, 4
- Elevated ESR and CRP are typically present, though normal values do not exclude the diagnosis 1, 2
- This represents a true ophthalmologic emergency requiring immediate high-dose corticosteroids to prevent bilateral blindness 4, 2
Rare Alternative Vasculitic Causes
2. Eosinophilic Granulomatosis with Polyangiitis (EGPA/Churg-Strauss)
- Rare multisystem inflammatory disease with asthma, eosinophilia, and vasculitic involvement 5
- Can present with A-AION in the context of systemic disease with marked eosinophilia 5
- Requires prompt glucocorticoid therapy similar to GCA 5
3. Polyarteritis Nodosa
- Systemic necrotizing vasculitis that can rarely affect the optic nerve head circulation 3
- Typically presents with other systemic manifestations of medium-vessel vasculitis 3
4. Systemic Lupus Erythematosus (SLE)
- Can cause vasculitic complications including arteritic optic neuropathy 1
- Patients with SLE have 3.5 times higher incidence of vascular occlusive events 1
5. Takayasu Arteritis
- Large-vessel vasculitis that can affect ophthalmic circulation 3
- More common in younger patients, particularly Asian women 3
6. Behçet's Disease
- Can cause vasculitis affecting the optic nerve, though posterior segment involvement is more typical 3
7. Wegener's Granulomatosis (Granulomatosis with Polyangiitis)
- Rare cause of arteritic optic neuropathy in the context of systemic ANCA-associated vasculitis 3
8. Microscopic Polyangiitis
- Small-vessel vasculitis that can rarely involve optic nerve head circulation 3
9. Cogan's Syndrome
- Rare inflammatory condition with ocular and audiovestibular manifestations that can include vasculitic optic neuropathy 3
10. Syphilitic Arteritis
- Infectious vasculitis from tertiary syphilis can rarely cause arteritic-pattern optic neuropathy 3
Critical Clinical Distinction
The distinction between arteritic and non-arteritic AION is paramount because:
- A-AION requires immediate systemic corticosteroids to prevent irreversible bilateral blindness 4, 2
- Non-arteritic AION (NA-AION) has no proven acute treatment and different risk factors (hypertension, diabetes, nocturnal hypotension, small optic disc) 4, 6
- Missing GCA diagnosis leads to devastating bilateral visual loss that is entirely preventable 3, 4
Key Diagnostic Features of A-AION
- Optic disc swelling with absence of emboli (unlike retinal artery occlusion) 1
- Typically affects patients over 50, more commonly over 70 years 2, 7
- Pale disc edema rather than hyperemic edema 6
- Associated systemic symptoms in most cases (though can be occult) 1, 2
- Requires temporal artery biopsy if ESR/CRP suggest GCA 1