Case of the Month

Edited by Robert N. Johnson, MD

Figure 1A and B: Color photograph of the right disc and macula. Note the pallid edema of the optic nerve. Scattered drusen are present in the macula

Case History

An 82-year-old Caucasian man presented with the complaint of sudden onset vision loss in the right eye of 2 days duration. On examination, visual acuity was hand motions in the right eye and 20/25 in the left eye. There was an afferent pupillary defect in the right eye. The anterior segment examination was unremarkable. Dilated examination of the right eye revealed pallid disc edema (Figures 1A and B), while the left eye showed a normal optic nerve. Fluorescein angiography revealed markedly delayed choroidal filling in the right eye and normal circulation in the left eye (Figures 2A-D).

Figures 2A-D: Fluorescein angiogram of the right (A, B and D) and left (C) eye. Note the choroidal nonperfusion in the early phases of the angiogram of the right eye. The choroid did show filling in the late phases of the angiogram (D). The left eye showed only hyperflourescent changes due to the drusen.

Differential Diagnosis

Non-arteritic anterior ischemic optic neuropathy,  giant cell arteritis, polyarteritis nodosa, Churg-Strauss syndrome, granulomatosis with polyangiitis, systemic lupus erythematosis, rheumatoid arthritis, relapsing polychodritis, syphilis, herpes zoster.

Additional History and Diagnosis

The patient denied headache, neck pain, tenderness of the scalp, jaw or tongue claudication, and fever. Given his age, the pallid disc edema, and choroidal ischemia, there was high suspicion for giant cell arteritis, and he was immediately started on high-dose systemic corticosteroids. Laboratory testing revealed an erythrocyte sedimentation rate of 96 mm/hr and a C-reactive protein of 83.5 mg/L. A temporal artery biopsy was performed, which revealed chronic inflammation, marked intimal thickening, and disruption of the elastic lamina, confirming the diagnosis of giant cell arteritis.

Discussion

Giant cell arteritis (GCA), also referred to as temporal arteritis, is a systemic large vessel vasculitis that can cause ischemic optic neuropathy, headaches, jaw claudication, and stroke.¹

GCA is a disease of the elderly, rarely affecting individuals less than 50 years, with a mean age of presentation of 70-75 years.¹ The vasculitis typically affects branches of the external carotid artery, resulting in headaches, scalp tenderness, and jaw and/or tongue claudication. Patients may present with systemic symptoms such as malaise, fever, and fatigue. Stroke may occur if the vertebral and basiliar arteries become involved. Involvement of the subclavian and brachial arteries may result in upper limb claudication. Aortitis has been reported in 10-20% of patients and may lead to aortic aneurysm.¹

The classic ocular finding of GCA is arteritic anterior ischemic optic neuropathy (AAION), which occurs due to vasculitis and subsequent infarction of the posterior ciliary arteries.² As in the case presented here, AAION in the absence of other GCA-related signs and symptoms may be the presenting feature of the disease.³ Patients with AAION typically report acute onset vision loss and are found to have pallid disc edema on clinical exam. On occasion GCA may cause posterior ischemic optic neuropathy, in which case the disc appears normal in the acute presentation.¹

As is shown in the case presented here, fluorescein angiography may reveal delayed choroidal perfusion, which again is attributed to vasculitic involvement of posterior ciliary arteries leading to choroidal infarction.² Patients with GCA may present with a triangular shaped area of choroidal non-perfusion in the temporal macula, known as the Amalric triangular syndrome (see: Sept-2010, West Coast Retina Case of the Month).⁴

Other ocular findings in GCA include cotton wool spots and retinal hemorrhages (which may precede ischemic optic neuropathy), cilioretinal artery occlusion (given its derivation from the posterior ciliary circulation), and ocular ischemic syndrome.² Patients may also present with diplopia due to ischemia of the extraocular muscles.1

The diagnosis of GCA relies on suggestive symptoms and clinical findings and is supported by laboratory studies showing elevated erythrocyte sedimentation rate, C-reactive protein, and platelets. Definitive diagnosis is made with temporal artery biopsy.²

Treatment with high dose systemic corticosteroids should be started promptly if GCA is suspected, with the goal of preventing loss of vision in the fellow eye or involvement of other systems. Left untreated, fellow eye involvement occurs in up to 95% of cases.¹ Temporal artery biopsy should be performed within 1-2 weeks of starting steroids. Prolonged steroid therapy is often required, and relapses are common. Recently, tocilizumab, an interleukin-6 inhibitor, has shown promise in preventing disease relapses.⁵

Other less common causes of arteritic anterior ischemic optic neuropathy aside from GCA include polyarteritis nodosa, Churg-Strauss syndrome, granulomatosis with polyangiitis, systemic lupus erythematosis, rheumatoid arthritis, relapsing polychodritis, syphilis, and herpes zoster and should be considered in the appropriate clinical context.^2,6

References

1. Denniston AK, Gayed M, Carruthers D, et al. Rheumatic Disease. In: Ryan SJ, Schachat AP, Sadda SR, eds. Retina. Fifth ed. Elsevier:1415-1440.
2. Agarwal A. Arteritic Anterior Ischemic Optic Neuropathy (a-AION). In: Agarwal, A. Gass’ Atlas of Macular Diseases. Fifth ed. Elsevier:1288-1290.
3. Hayreh SS, Podhajsky PA, Zimmerman B. Ocular manifestations of giant cell arteritis. Am J Ophthalmol 1998;125:509-520.
4. Nemiroff J, Phasukkijwatana N, Vaclavik V, et al. The spectrum of Amalric triangular choroidal infarction. Retin Cases and Brief Rep 2017;11:S113-S120.
5. Stone JH, Tuckwell K, Dimonaco S, et al. Trial of Tocilizumab in Giant-Cell Arteritis. N Engl J Med 2017;377:317-328.
6. Kline LB. The Swollen Optic Disc. In: Kline LB, Foroozan R. Neuro-Ophthalmology Review Manual. Seventh ed. Slack:139-156