What is the treatment for Arteritic Anterior Ischemic Optic Neuropathy (AAION)?

Treatment of Arteritic Anterior Ischemic Optic Neuropathy (AAION)

Immediate high-dose systemic corticosteroid therapy is the definitive treatment for Arteritic Anterior Ischemic Optic Neuropathy (AAION) to prevent vision loss in the contralateral eye and must be initiated as soon as the diagnosis is suspected, without waiting for confirmatory tests.

Diagnosis and Initial Management

Clinical Presentation

• Sudden, painless monocular vision loss
• Optic disc swelling
• Visual field defects (typically altitudinal)
• Symptoms of giant cell arteritis (GCA):
  • Temporal headache
  • Scalp tenderness
  • Jaw claudication
  • Constitutional symptoms (weight loss, fatigue, fever)
  • Myalgia, especially of upper limbs 1

Diagnostic Evaluation

1. Laboratory tests (order immediately):

   • Erythrocyte sedimentation rate (ESR)
   • C-reactive protein (CRP)
   • Complete blood count (look for anemia, thrombocytosis) 1

2. Imaging (perform urgently):

   • Ultrasound of temporal arteries
   • MRI of brain and orbits to rule out other causes 1

3. Temporal artery biopsy:

   • Should be performed within 1-2 weeks of starting treatment
   • Note: Normal inflammatory markers do not rule out GCA (proceed with treatment if clinical suspicion is high) 2

Treatment Algorithm

Immediate Treatment

1. High-dose systemic corticosteroids (start immediately upon suspicion):

   • Initial dose: Intravenous methylprednisolone 250mg three times daily for 3 days 1, 2
   • Alternative: Oral prednisone 60mg daily if IV treatment not available 1

2. Monitor for response:

   • Assess symptoms (headache, jaw claudication should improve within 24-48 hours)
   • Check ESR/CRP within 1-2 weeks (should show significant reduction) 3

Maintenance Therapy

1. Transition to oral prednisone:

   • After IV therapy, switch to oral prednisone 60mg daily 1
   • Taper gradually over 12+ months:
     • Target dose of 15-20mg/day within 2-3 months
     • Target dose of ≤5mg/day after 1 year 1

2. Monitor for relapse:

   • Regular ESR/CRP testing
   • Watch for recurrence of GCA symptoms
   • Adjust steroid dose accordingly 1

Adjunctive Treatments

Potential Adjuncts to Consider

• Prostaglandin E1 (PGE1):
  • May be considered as an adjunctive vasodilator therapy to improve ocular blood flow
  • Limited evidence suggests possible visual acuity improvement when combined with steroids 4

Prevention of Complications

1. Bone protection:

   • Calcium and vitamin D supplementation
   • Consider bisphosphonates for long-term steroid use

2. Gastric protection:

   • Proton pump inhibitor or H2 blocker

3. Blood glucose monitoring:

   • Regular checks for steroid-induced hyperglycemia

Prognosis and Follow-up

Visual Outcome

• Vision lost due to AAION is usually permanent
• Primary goal of treatment is to prevent involvement of the contralateral eye 5

Follow-up Schedule

• Ophthalmologic examination: Weekly for first month, then monthly
• ESR/CRP: Every 2-4 weeks initially, then every 1-3 months
• Temporal artery biopsy results review

Important Caveats

1. Do not delay treatment while awaiting biopsy or other test results if clinical suspicion is high 1

2. Normal inflammatory markers do not rule out GCA - approximately 5-10% of patients with biopsy-proven GCA may have normal ESR and CRP 2

3. Bilateral involvement can occur rapidly if treatment is delayed - consider AAION an ophthalmologic emergency 1, 3

4. Differentiate from non-arteritic AION which has different management (AAION requires higher steroid doses and longer treatment) 5

5. Monitor for steroid side effects throughout the treatment course