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Show Journal of Neuro- Ophthalmology 20( 4): 273- 275, 2000. © 2000 Lippincott Williams & Wilkins, Inc., Philadelphia Ophthalmic Artery Microembolism in Giant Cell Arteritis Barbara Schauble, MD, Christine A. C. Wijman, MD, Behrooz Koleini, MD, and Viken L. Babikian, MD A 70- year- old man presented with a history of headache and sudden loss of vision of the left eye. Funduscopic examination showed sector retinal edema and hemorrhage as well as optic disc swelling consistent with anterior ischemic optic neuropathy. The Westergren sedimentation rate was 66 mrn/ h. Temporal artery biopsy was consistent with giant cell arteritis. Routine transcranial Doppler testing performed on a Pioneer 2020 instrument ( Nicolet Vascular, Inc., Golden, CO) equipped with special software for microembolus detection showed a micro-embolic signal in the left ophthalmic artery. During a subsequent monitoring study, microembolia signals were detected in the anterior and middle cerebral arteries, bilaterally. Microembolism can occur in giant cell arteritis. Ophthalmic artery microembolism can be detected in vivo by transcranial Doppler ultrasonography. This new imaging capability can potentially be useful when evaluating patients with vascular disorders of the eye. Key words: Ophthalmic artery embolism- Retinal ischemia. Giant cell arteritis ( GCA) is a generalized, necrotizing arteritis characterized by inflammation of the cranial branches of the aortic arch as well as the coronary arteries. Ophthalmologic and neurologic manifestations occur in more than 30% of patients. Although retinal ischemic events are considered the result of inflammatory obstruction of vessels with or without distal embolism ( 1), the exact mechanism of ischemia in this context is not well understood. The " gold standard" to diagnose GCA is histopathologic confirmation of the clinical impression. Supportive evidence can be obtained by contrast angiography and color duplex imaging. These modalities rarely provide information regarding the mechanism of disease. In patients with atherosclerotic cerebrovascular disease, microembolic signals ( MES) detected by transcranial Doppler ultrasonography correspond to platelet-fibrinogen microemboli ( 2). MES are predictors of re- Manuscript received January 3, 2000; accepted July 17, 2000. From the Departments of Neurology and Ophthalmology, Boston University School of Medicine, Boston, Massachusetts. Address correspondence and reprint requests to Viken L. Babikian, MD, Department of Neurology, Boston University School of Medicine, Boston VA Medical Center, 150 South Huntington Avenue, Boston, MA 02130. current retinal and hemispheric ischemic events and are associated with symptoms of retinal ischemia ( 3). The presence of MES in patients with GCA has not been studied. In this report, we present transcranial Doppler findings in a man with biopsy- proven GCA. CASE REPORT A 70- year- old man had a 3- day history of sudden loss of vision OS. He volunteered a 1- week history of jaw pain when chewing, bifrontal headaches, and fatigue. He denied muscle aches and weight loss. The medical history and general examination were nonrevealing. There were no cardiac murmurs. Examination of the forehead showed a firm and tender left temporal artery. Ophthalmologic examination showed a best visual acuity of 20/ 30 OD and counting fingers at 3 feet OS. A left afferent pupillary defect was present. A sector of retinal edema and hemorrhage was seen temporal to the optic disc OS, and was suspicious for an occluded cilioretinal artery. In addition, diffuse swelling of the left optic disc was consistent with anterior ischemic optic neuropathy. GCA was suspected clinically, and intravenous methylprednis-olone was administered. Westergren sedimentation rate was 66 mm/ h, and the hemogram was normal. A duplex study showed less than 30% stenosis of the extracranial carotid arteries. The patient refused echocardiographic studies. Results of the electrocardiogram were normal. Biopsy of the left temporal artery confirmed the diagnosis of GCA ( Fig. 1). Transcranial Doppler examination 5 days after presentation on a Pioneer 2020 instrument ( Nicolet Vascular Inc., Golden, CO) showed no evidence of internal carotid artery siphon stenosis. A MES was detected in the left ophthalmic artery ( Fig. 2) during the regular examination. Subsequent MES monitoring studies indicated multiple MES in the middle and anterior cerebral arteries, bilaterally. During a 10- month follow- up period, the visual acuity of the OS remained the same, and there were no retinal, hemispheric, or systemic ischemic events. The dose of prednisone was tapered, and the Westergren sedimentation rate normalized. 273 2 74 B. SCHA UBLE ET AL. FIG. 1. Biopsy of the left temporal artery. Intimal hyperplasia and focal inflammatory infiltration of the intima and adventitia ( left panel; H& E stain; low magnification). A multinucleated giant cell is seen in the adventitia ( right panel). DISCUSSION Our findings show that microembolism can occur in GCA. Whether it contributes to ocular or cerebral ischemic symptoms in this disease remains unknown. Although MES can be detected in approximately 5% to 10% of controls without symptoms of retinal or brain ischemia, their frequency is low and their arterial distribution is limited in that setting. The finding of multiple MES in both anterior and middle cerebral arteries and the left ophthalmic artery of our patient suggests the presence of an active source of emboli, possibly located in the aortic arch or cardiac chambers. The coronary arteries and aortic arch can be affected by the arteritic process in GCA. However, the source of microemboli could not be determined. Retinal emboli are often detected clinically, but the true prevalence of retinal embolism remains unknown for lack of a technology that permits to reliably detect these particles. Our observation suggests that it is possible to detect ophthalmic artery microemboli with transcranial Doppler. However, several technical limitations, including the development of a device to immobilize the probe over the orbit, need to be resolved. In addition, the issue of safety needs to be addressed. This is a critical limitation because prolonged exposure to ultrasound can cause cataract formation. Although insonation of the ophthalmic artery and internal carotid artery siphon at FIG. 2. Insonation of the ophthalmic artery through the orbital window at a depth of 46 mm. Flow is antegrade. The peak systolic flow velocity of 80 cm/ s is mildly elevated. A microembolic signal is seen during the first heartbeat ( arrow). lJkW_. ff J Neuro- Ophthalmol, Vol. 20, No. 4, 2000 OPHTHALMIC ARTERY MICROEMBOLISM IN GIANT CELL ARTERITIS 2 75 reduced ultrasound power is now considered an integral part of routine transcranial Doppler testing, the safety of prolonged exposure associated with MES monitoring is not established. Further research should help clarify this point. Acknowledgement: The authors thank Dr. Flaviu Romanul for reviewing the biopsy slides and Val Pochay for his technical assistance in preparing the graphic material. REFERENCES 1. Cullen JF, Coleiro JA. Ophthalmic complications of giant cell arteritis. Surv Ophthalmol 1976; 20: 247- 60. 2. Sitzer M, Muller, W, Siebler M, et al. Plaque ulceration and lumen thrombus are the main sources of cerebral microemboli in high grade internal carotid artery stenosis. Stroke 1995; 26: 1231- 3. 3. Wijman CA, Babikian VL, Matjucha IC, et al. Cerebral microem-bolism in patients with retinal ischemia. Stroke 1998; 29: 1139- 43. J Neuro- Ophthalmol, Vol. 20, No. 4, 2000 |
