9 - arteritic AION (AAION)

What is the most common cause of acute optic neuropathy on the elderly?

AION

What is AAION associated with?

giant cell arteritis

What is the pathogenesis of AAION?

occlusion or infarction of the blood supply at the lamina cribrosa

what are other associated systemic diseases with AAION?

1. SLE

2. polyarteritis nodosa

3. RA

4. Behcet's disease

What is giant cell arteritis (GCA)?

inflammatory vasculitis → auto-immune response to arterial elastic tissue causes vessel narrowing and occlusion

What arteries does GCA affect?

medium and large arteries → especially temporal artery and posterior ciliary arteries

What is the most common vasculitis in the elderly?

giant cell arteritis aka temporal arteritis

What are the risk factors of GCA?

1. older age (>60)

2. female

3. Caucasian

4. FHx

5. low BMI

6. smoking

What condition is GCA associated with?

polymyalgia rheumatica

When do the systemic symptoms of GCA occur?

several weeks to months before ocular symptoms

What are the systemic symptoms of GCA?

1. new onset headaches

2. jaw claudication

3. scalp tenderness

4. muscle aches/stiffness in neck or shoulders

5. weight loss

6. low grade fever

7. fatigue

What are the systemic signs of GCA?

1. elevated ESR (>40mm/hr)

2. elevated CRP (>2.5mg/dl)

3. anemia

4. tortuous, swollen, tender temporal artery without palpable pulse

5. positive imaging or biopsy

How do you calculate normal ESR?

men: age/2

women: (age+10)/2

What are the two imaging scans for GCA that are not really used?

1. MRI angiography → invasive, risks with contrast dye, false negs

2. PET scan

What are the two imaging/tests for GCA that are used to diagnose GCA?

1. ultrasonography

2. temporal artery biopsy

What should you look for on ultrasonography when determining GCA?

halo sign → vessel inflammation d/t obstruction of lumen

What may you find on temporal artery biopsy that indicates GCA?

1. disruption of internal elastic lamina d/t persistent inflammation

2. granulomatous inflammation with infiltration of giant cells

3. degeneration of smooth muscle cells

4. swollen endothelium

5. fibrosis, hyaline thickening, thrombosis

Why is GCA a medical and ocular emergency?

if treated → no increased mortality

if untreated → can cause stroke, aortic aneurysm, MI, and blindness (in one or both eyes)

When does GCA resolve?

self limiting within 1-2 years → BUT we treat because of risk of death and blindness

In those with GCA, who loses their vision?

those who have AAION → rarely with CRAO or ischemic retinopathy

In people who have had vision loss in one eye due to GCA, when is the risk for blindness in the other eye (binocular vision loss) reduced?

with treatment or after 6 months

What are the ocular symptoms of GCA?

1. amaurosis fugax → days or months before AAION occurs

2. blurred vision

3. diplopia

What are the ocular signs of GCA?

1. AAION

2. vision loss

3. ptosis

4. CRAO

5. ophthalmoparesis - weakness or paresis of one of EOMs

What are the rare ocular signs that can be seen with GCA?

1. anterior segment ischemia

2. marginal corneal ulceration

3. bilateral uveitic glaucoma

4. hallucination

5. conjunctivitis

What are the symptoms of AAION?

1. sudden, painless vision loss

2. may have GCA symptoms

What are the signs of AAION?

1. decreased VAs → majority 20/200 or worse

2. APD

3. decreased CV/red desaturation

4. pale, swollen ONH → may have peripapillary hemes

5. constricted retinal arterioles

6. NF bundle defects → majority inferior altitudinal

What are the treated vs untreated outcomes of AAION?

vision loss is generally irreversible → unless pulse of steroid given within 36 hours of acute vision loss

if untreated → 65% risk of attack in other eye within hours/days

What are the differentials to consider with AAION?

1. NAAION

2. CRVO

3. papilledema

4. compressive optic neuropathy

5. buried ONH drusen

6. optic neuritis

What is the immediate management of AAION?

refer to ER and ophthalmologist

1. give high dose systemic steroids

2. get CBC, ESR, CRP

3. get temporal artery biopsy

4. 75 mg of Aspirin (not proven to help)

Why do we give high dose systemic steroids to AAION patients?

to decrease chance of vision loss in other eye and relieve symptoms → does not improve vision, caution in diabetics

What is the long term treatment for AAION?

1. maintain normal symptoms and ESR/CRP for 6-12 months

2. look out for steroid complications

3. methotrexate +/or abatacept as maintenance meds

what is the taper schedule for steroids in tx for AION?

decrease by 10 mg every 2 wks to 20 mg

decreased by 2.5 mg every 2-4 wks to 10 mg

decrease by 1 mg every 1-2 months

what is the treatment for GCA?

1. Tocilizumab (Actemra) → IL-6 receptor agonist

2. Upadacitinib (RINVOQ) → janus kinase inhibitor

what are potential systemic complications for GCA?

1. myocardial infarction

2. aortic dissections