Clinical Challenges
A Typical Friday Afternoon
Diagnosing and treating arteritic ischemic optic neuropathy -- fast.
Clinical Challenges with Eric Schmidt, O.D.

There's something marvelous about Fridays. The prospect of 2 days off always makes me happy. But there's another thing about Fridays . . . .

It seems that the toughest, most serious clinical challenges present themselves then, usually close to closing time. I know this phenomenon isn't unique to me; it comes with the territory. But nonetheless, when this type of challenge arises, it sets all of us up for an uneasy weekend. Here, I'll present an example from my practice that might help you in your own.

The "Vida Blues"

When I walked into the exam room to greet Vida, she made no bones about three things:

• She was confused as to why she had to be here.
• She was irritated about being sent to my office and wasting her Friday afternoon.
• Her eyes were fine.

As I talked with this 83-year-old lady, I tried to explain that her doctor was quite concerned about her left eye and was worried about the potential for very serious damage if it was left unattended for much longer. Despite my best efforts, this didn't pacify her well at all.

Looking into it

I'd received a call earlier that day from Vida's long-time optometrist, who explained that Vida had come in for a comprehensive exam, complaining only that her "eyeglasses no longer worked." She didn't mention redness, discharge or pain and felt overall that she wasn't having much trouble with her eyes.

Vida had lost the vision in her right eye 4 years earlier due to a "stroke" in that eye. Her optometrist had documented a decrease in vision OS from 20/40 2 years earlier to 20/80 today. He referred her to me because of a flame hemorrhage and possible disk swelling in the OS.

Vida told me that she used to see well in her right eye until 4 years ago, when she suddenly lost that vision. She said her left eye seemed fine and reiterated her need for new glasses.

Vida was taking celecoxib (Celebrex) for arthritis and acetaminophen (Tylenol) p.r.n. for pain. She stated that her health otherwise was fine. I measured her visual acuity (VA) to be light perception OD and 20/200 OS with her glasses. The OS improved with the pinhole occluder to 20/60.

I found a big change in her refraction OS. It had gone from pl-400 x 170, which is what her glasses were, to +0.50 -1.00 x 180. This improved her VA to 20/60 OS. The OD showed no improvement with refraction or pinhole.

Vida had a 6-mm, horizontally oval pupil OD (secondary to a cataract extraction) that exhibited a 3+ afferent pupillary defect (APD). The pupil OS was 4 mm, round and reactive with no APD. Extraocular muscles showed no restrictions or pain on movement.

Looking deeper

Examination of the anterior segments showed a well-positioned posterior chamber intraocular lens with no posterior capsule opacification OD. I saw mild stromal haze but no signs of active inflammation or infection. The OS showed a well-centered posterior chamber intraocular lens with no posterior capsule opacification.

The cornea OS was hazier than on the right, with limbal vascular encroachment 360 degrees. I noted 3+ endothelial pigment deposition OS. The anterior chamber was deep, with no cell or flare. Vida's intraocular pressure measured 24 mm Hg OD and 15 mm Hg OS. My technician dilated Vida's eyes and checked her blood pressure. It was 162/84.

When I examined Vida's fundus, I found a very pale, atrophic optic nerve head OD. I saw marked attenuation and sheathing of the arterioles but no active hemorrhages or disk swelling. Vida had obviously suffered an ischemic optic neuropathy (ION) in that eye, which left her with light-perception vision only.

When I examined Vida's OS, I understood why her doctor arranged for such an urgent referral. The optic nerve head was mildly edematous throughout all 360 degrees. In addition, I saw one large, flame-shaped hemorrhage just off the disk margin at 1:00 (see above). A very prominent 4+ spontaneous venous pulse was evident as well.

A process of elimination

The most pressing chore now was to determine the etiology of the unilateral disk edema. The differential diagnosis list was short but full of potentially serious conditions, especially these:

• ischemic optic neuropathy (ION)
• optic neuritis
• impending central retinal vein occlusion
• central retinal artery occlusion
• open-angle glaucoma
• compressive optic neuropathy
• Foster Kennedy syndrome.  In Foster Kennedy syndrome, the patient has optic atrophy in one eye and disk edema in the other, secondary to an intracranial tumor of long duration. Although this was a possibility, it seemed unlikely that the syndrome would have presented the way it did in Vida's case. I reserved it as my third choice.

That left an impending central retinal vein occlusion or ION as the most likely etiologies. ION is the more sight-threatening, so I needed to rule it out first. I ordered an erythrocyte sedimentation rate (ESR) from the hospital lab and told Vida to wait there until I received the results (about an hour). I also asked her specifically about symptoms related to giant cell arteritis (GCA). She admitted to malaise and weight loss, plus frequent headaches.

The final piece of the puzzle

Vida's ESR result came back as 76 mm/hr, which was elevated. This was all the evidence I needed to diagnose her problem as arteritic ION. Now it was imperative to minimize the damage to her only remaining good eye.

Typically, I'd procure a temporal artery biopsy to rule out GCA before placing a patient on steroids, but now it was after 6:00 p.m. on a Friday. I reached a vascular surgeon, who said he'd wait until Monday morning to perform the biopsy.

But I couldn't take the chance of Vida's remaining vision being lost between now and then. Arteritic ION can rapidly cause an ischemic event to choke the optic nerve, leaving it permanently and profoundly damaged. I surmised that that is what happened to Vida's right eye, and I didn't want to give it more opportunity to further damage the left.

GCA waits for no one

I placed Vida on 80 mg oral prednisone. I saw her the next afternoon, and her VA was 20/60 OS. The temporal artery biopsy was performed on Monday; the pathology report came back positive for GCA. Vida definitely had an arteritic ION and needed to stay on oral prednisone.

I took repeat ESRs every week and kept her on 80 mg until the findings normalized. I very slowly tapered the prednisone, ordering an ESR each time I changed her dosage.

Fortunately, Vida's VA has remained 20/60 OS. It took more than 4 months of steroid use before her ESR remained normal. I'll continue to monitor her every 6 months. Both her internist and I will order regular ESRs for her.

When GCA pops up in a patient with only one sighted eye, it raises our level of worry. We must understand the beneficial role of prednisone in treating this disease and also understand that a prompt ESR is key to diagnosing it (even if it is a Friday afternoon)! 

Contributing Editor Eric Schmidt, O.D., is director of the Bladen Eye Center in Elizabethtown, N.C. He can be reached at KENZIEKATE@aol.com.