DISEASE
Arteritic Anterior Ischemic Optic Neuropathy (AAION) is an acute, often painful optic neuropathy that occurs predominantly in elderly patients over age 50 but with increasing incidence each decade thereafter and can cause permanent loss of vision. Ischemia occurs at the head of the optic nerve in relation to structural crowding of the nerve fibers, impairing perfusion and leading to optic disc edema.
There is thought to be a genetic component to the disease, as evidence shows Caucasians are affected at a higher rate, but it has been reported in many different races and ethnicities.
Patients on the exam can often show many different signs to lead to the right diagnosis. Some important signs on the exam include seeing the optic nerve swollen and pale (chalky color of the optic disc seen) upon ophthalmoscope, retinal cotton wool spots located at the posterior pole, and sometimes central retinal artery occlusion due to this artery and the SPCA both deriving from the ophthalmic artery.
Physical exam may also reveal diplopia, ptosis, nystagmus, or pain or nodularity upon palpitation of the temporal artery.
An elevated erythrocyte sedimentation rate (ESR) (up to 70-120mm/min) and/or serum C reactive protein (CRP) may aid in diagnosis.
A 97% specificity for temporal arteritis has been reported in cases of AAION in which both ESR and CRP were elevated.
Patients with NA-AION do not show these types of abnormalities. Other tests in GCA include: platelet count for possible thrombocytosis, leukocyte count, and hemoglobin levels.
Platelet count is often elevated acutely in cases of Arteritic Anterior Ischemic Optic Neuropathy (AAION) and can be used in conjunction with elevated ESR and CRP levels to make a preliminary diagnosis.
Confirmation of the diagnosis of temporal arteritis by superficial temporal artery biopsy is recommended in cases of AION with clinical suspicion of arteritis.
Positive biopsy findings (intimal thickening, internal limiting lamina fragmentation, and chronic inflammatory infiltrate with giant cells) are confirmatory for GCA.
A negative biopsy doesn’t rule out arteritis (both discontinuous arterial involvement (‘skip lesions’) and solely contralateral temporal artery inflammation may result in false-negative results) with recent reports showing a 3-5% false-negative error rate.
If an initial biopsy is found to be negative and suspicion for GCA is high, a biopsy of the contralateral temporal artery should be considered.
Magnetic Resonance Imaging has recently provided evidence that it may be able to distinguish between Arteritic Anterior Ischemic Optic Neuropathy (AAION) and NA-AION.
The imaging scores identified the acute stage of giant cell arteritis-related anterior ischemic neuropathy with a statistically significant relationship between the side of the AION and the side of the “central bright spot” i.e. optic nerve head enhancement.
Ultrasound(US) of the temporal artery can provide some insight as well. It reveals characteristic dark wall swelling (halo) and acute occlusions in active Arteritic Anterior Ischemic Optic Neuropathy (AAION).
The temporal artery duplex ultrasound has demonstrated a sensitivity and specificity of 87% and 96% respectively with regard to clinical diagnosis.
US provides a noninvasive technique that can be used after seeing a patient with elevated ESR, CRP, and platelet levels.
It remains to be proven if ultrasound will one day be able to obviate the temporal artery biopsy which remains the current gold standard.
MANAGEMENT
Fundus Explorer Pro
Photograph the retinal findings described here with the phone already in your pocket — 22 D optics and built-in illumination in one handheld unit.
From Choroida — the team behind this siteSteroids
Early steroid treatment is essential. High-dose systemic corticosteroids are standard. Intravenous methylprednisolone at 1g/day for the first three days has been recommended for severe cases but has not been subjected to a head-to-head trial against oral steroids in GCA.
Oral prednisone in the range of 60-100mg/day may be used initially and for follow-up to intravenous pulse therapy.
Treatment is usually continued at a high dose for several months before beginning taper but may be required for several years in severe cases to avoid permanent vision loss.
Tocilizumab is a monoclonal antibody humanized for the treatment of AAION. It works by binding to the alpha chain on the human interleukin 6 (IL-6) receptor.
Through binding, tocilizumab blocks signaling and downregulates the acute phase reactions. This monoclonal antibody has demonstrated effectiveness as a non-corticosteroid therapy for those dealing with Arteritic Anterior Ischemic Optic Neuropathy (AAION).
In some of the most recent literature, tocilizumab was very effective against corticosteroid-resistant AAION, causing symptoms to halt immediately upon the first dose.
However, more research into its ability to serve a protective role against bilateral blindness must be conducted to rule out any confounding variables. Tocilizumab received FDA approval in 2017 for the treatment of giant cell arteritis.
Other Treatment
Methotrexate is one of the most widely studied “steroid-sparing” agents. Also known as a chemotherapy agent, methotrexate has demonstrated some great benefits to those patients dealing with Arteritic Anterior Ischemic Optic Neuropathy (AAION).
A recent study indicated that the drug was able to significantly increase the probability of achieving a sustained discontinuation of using corticosteroids as well as decreasing the risks of relapses with the disease.
Corticosteroid therapy while effective, can be very toxic leading to almost 60% of individuals getting major side effects such as diabetes or cataracts.
At this time, methotrexate looks to serve best as a way to reduce exposure to corticosteroids and their adverse effects.
The best therapeutic option may be conjunction therapy, in order to decrease exposure and possible relapse for those patients with AAION.
Without treatment, visual loss occurs in 54-95% of GCA patients), typically within four months. With corticosteroid therapy, the rate of such decline is reduced to an estimated 13%.
Visual recovery of the affected eye that has treatment is poor with a 15-34% improvement rate, which is higher with intravenous therapy.
Worsening visual acuity has been reported in 9-17% despite therapy. Vision loss in both eyes is possible; however, most cases have indicated it to be frequent when one patient is unaware of vision loss in the first eye.
The incidence of having this bilateral involvement involves timing heavily as well as how aggressively corticosteroid therapy is utilized.
However, if left untreated, bilateral vision loss can proceed quickly from either optic nerve, retinal, or choroidal ischemia in up to 50% of cases.
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From Choroida — the team behind this siteREFERENCES
- Sohan Singh Hayreh, Ischemic optic neuropathy, In Progress in Retinal and Eye Research 2009; Volume 28, Issue 1, pp. 34-62,
- Arnold AC: Ischemic optic neuropathies. Ophthalmol Clin North Am 2001; 14: pp. 83-98
- Balducci, N., Morara, M., Veronese, C. et al. Graefes Arch., Optical Coherence Tomography, Clin Exp Ophthalmol, 2017; 255: 2255.
- Vionnet, Julien, et al. “Tocilizumab for giant cell arteritis with corticosteroid-resistant progressive anterior ischemic optic neuropathy.” Joint Bone Spine 2017.
- Beck RW, Servais GE, and Hayreh SS: Anterior ischemic optic neuropathy. IX. Cup-to-disc ratio and its role in pathogenesis. Ophthalmology 1987; 94: pp. 1503-1508
- Minagar, Alireza, et al. “Neurologic presentations of systemic vasculitides.” Neurologic clinics 28.1 2010: 171-184.
Test yourself
A few questions straight from this article.
-
Arteritic anterior ischaemic optic neuropathy occurs predominantly in which age group?
AAION is an acute, often painful optic neuropathy of elderly patients over 50, and its incidence climbs with each decade thereafter. -
What does the optic disc look like in arteritic anterior ischaemic optic neuropathy?
On ophthalmoscopy the disc is swollen and pale, the classic chalky colour, often with cotton wool spots at the posterior pole. -
Why can a central retinal artery occlusion accompany arteritic anterior ischaemic optic neuropathy?
Because the central retinal artery and the short posterior ciliary arteries both derive from the ophthalmic artery, arteritic disease can occlude both and produce a central retinal artery occlusion alongside the optic neuropathy. -
When both ESR and CRP are elevated in AION, what specificity for temporal arteritis has been reported?
Elevation of both ESR and CRP carries a reported 97% specificity for temporal arteritis, and patients with non-arteritic AION do not show these inflammatory abnormalities. -
Why can a temporal artery biopsy be falsely negative in giant cell arteritis?
Discontinuous arterial involvement (skip lesions) or inflammation only in the contralateral artery give a 3-5% false-negative rate, so a contralateral biopsy should be considered when suspicion remains high. -
What does duplex ultrasound of the temporal artery show in active arteritic AION?
Temporal artery ultrasound reveals the characteristic dark wall swelling or halo with acute occlusions, achieving 87% sensitivity and 96% specificity, although biopsy remains the gold standard. -
Which corticosteroid regimen is recommended for severe arteritic anterior ischaemic optic neuropathy?
Early high-dose systemic steroid is essential: intravenous methylprednisolone 1 g/day for the first three days is recommended in severe cases, with oral prednisone 60-100 mg/day used initially or as follow-on. -
How does tocilizumab act in giant cell arteritis?
Tocilizumab is a humanised monoclonal antibody that binds the alpha chain of the human interleukin-6 receptor, blocking signalling and downregulating the acute phase response; it gained FDA approval for giant cell arteritis in 2017. -
What role does methotrexate play in arteritic anterior ischaemic optic neuropathy?
Methotrexate is the most widely studied steroid-sparing agent here, raising the chance of sustained corticosteroid discontinuation and lowering relapse risk, which matters because almost 60% of patients on steroids develop major side effects such as diabetes or cataract. -
How does corticosteroid treatment change the rate of visual loss in giant cell arteritis?
Untreated, visual loss affects 54-95% of patients, typically within four months; corticosteroid therapy cuts that to an estimated 13%, though recovery in an already affected eye remains poor.
Writes and reviews the clinical articles on Educate. Every post is checked against peer-reviewed sources before it goes live.
