Here we present a patient of Arab ethnicity who developed bilateral blindness after suffering from a simultaneous onset bilateral PION and a biopsy proven GCA. GCA is a granulomatous, medium to large vessel, inflammatory disease that can have devastating ischemic consequences to the eye [
5,
6]. It is considered a relatively unusual occurrence in Arabs [
7] and is more commonly encountered in Caucasian ethnicity [
8]. Its incidence is most marked among white individuals of Scandinavian descent [
9,
10], with one large Norwegian study finding an increasing incidence between 1972 and 1992 that subsequently plateaued. Women are more likely to be affected than men and the typical patient is in the 8th decade of life [
5,
9]. The typical symptoms of GCA include headache, scalp tenderness, jaw claudication, and loss of vision [
3]. Headache is a common symptom in GCA and occurs in more than two-thirds of patients [
11]. Visual impairments of varying degrees occur in one or both eyes in about 25 to 50% of GCA patients [
4,
12,
13]. PION from GCA is uncommon (Table
1), the visual loss is most frequently the result of anterior ischemic optic neuropathies (AION), followed by central or branch retinal arterial occlusions [
4,
8,
14]. In a prospective series of 170 patients with GCA, AION occurred in 81.2% of ocular ischemic cases, while PION occurred unilaterally in 5.9% and bilaterally in one patient [
4]. Approximately 10% of visual impairment was from CRAO [
4]. PION results from ischemia involving the retrobulbar part of the optic nerve [
4], and is classified by etiology as non-arteritic, arteritic or surgical (perioperative) [
4]. Typically, PION presents with monocular visual loss when non-arteritic and sequential visual loss when arteritic. Simultaneous bilateral visual loss is usually encountered in the perioperative type of PION [
15] where perfusion abnormalities to the eyes occur [
16]. In contrast to AION, the optic disc examination is normal in the acute setting of PION, with the development of optic atrophy on follow up assessments appearing about 6 weeks after the event [
17]. Findings on MRI are either normal or show hyper-intense signals on diffusion restricted images, while enhancement of the optic nerve with contrast can be seen in arteritic ischemic optic neuropathies [
18].
Table 1
Reports of posterior ischemic optic neuropathy secondary to giant cell arteritis
| 174 GCA 147 Biopsy proven GCA 48 Ophthalmic GCA | 2 (PION) | Both described as bilateral and recovered |
| 170 Biopsy proven GCA 85 Ophthalmic GCA | 6 (PION) | One described as Bilateral |
| 32 Biopsy proven ophthalmic GCA | 2 (PION) | African American cohort |
Danesh-Meyer et al. 2005 [ 21] | 34 Biopsy proven ophthalmic GCA | 2 (PION) | One had PION on one side and AION on the other side that was described as bilateral at presentation |
| 45 biopsy proven ophthalmic GCA | 2 (PION) | One had PION on one side and AION on the other side that was simultaneous onset |
| 327 GCA 245 Ophthalmic diagnosis 204 biopsy proven | 1 (PION) | |
| 102 Suspected ophthalmic GCA 7 biopsy proven | 1 (PION) | |
| 72 PION patients | 6 (Arteritic) | None simultaneous due to arteritis |
| 43 PION patients | 12 (Arteritic) | |
The current patient presented with a history of headache for one year that culminated in bilateral visual loss from optic nerve ischemia. The differential diagnosis for a presentation of acute optic neuropathy with headache includes arteritic ischemic optic neuropathy, infections (cat-scratch, syphilis), inflammatory (para-infectious, multiple sclerosis, systemic autoimmune, paraneoplastic, and sarcoidosis). GCA in the current scenario presented fairly typically, readily distinguishing it from other conditions. The ESR and CRP were high which suggested an inflammatory process and abnormal signals were seen on the MRI suggesting infarction.
Simultaneous and sudden complete blindness of both eyes due to PION is an unusual presentation in GCA. Bilateral visual loss is usually due to the sequential onset of AION, CRAO, or PION in any combination [
4,
15]. One cohort that looked at a small subgroup of simultaneous onset bilateral ischemic optic neuropathies found examination findings of different ages in each eye, raising the possibility that patients may not become aware of visual loss until it involves the other eye [
4]. Thus, an important consideration in the current case is defining how simultaneous was the onset. Our patient witnessed the visual loss occur while he was awake, and was found to have symmetrical exam findings when assessed at the referring center on the day of onset, and again at our center 5 days later with no clear disc abnormalities. There was diffusion restriction involving the right optic nerve with absence of both ophthalmic arteries by MRA. It was not surprising to find asymmetrical findings on MRI as PION changes may not always seen on MRI [
19], and our patient did not have imaging done until one week after the event reducing the possibility of witnessing acute changes. Asymmetry in the observed MRI signals of bilateral simultaneous onset post surgical PION have also been described [
20].