REVIEW ARTICLE
Three common ophthalmic emergencies Kristine Wyatt, PA-C
ABSTRACT Vision changes and ophthalmic complaints may represent potentially serious, sometimes fatal, systemic illnesses. This article summarizes the presenting signs and symptoms of retinal artery occlusion, giant cell arteritis, and oculomotor nerve palsy. Keywords: retinal artery occlusion, giant cell arteritis, amaurosis fugax, oculomotor nerve palsy, communicating artery aneurysm, ophthalmic emergencies
ARTERIAL OCCLUSIVE DISEASE A 66-year-old man presents with a complaint of a change in vision in his right eye. He describes a “blank spot” in his peripheral vision, which he first noted upon waking this morning. His past medical history is significant for mild hypertension and hypercholesterolemia. He has been diagnosed with bilateral mild cataracts. His prescribed medications are 81-mg aspirin, hydrochlorothiazide, pravastatin, and vitamins. He denies trauma, pain, flashes, floaters, headaches, jaw claudication, scalp tenderness, weight loss, and loss of appetite. On examination, he has corrected vision of 20/25 in each eye, and his pupils are equally round and reactive to light. Confrontation field testing shows a scotoma infero-temporally in the right eye, but intact peripheral vision in the left eye. Direct ophthalmoscopy is unremarkable. Pathophysiology The blood supply to the inner layers of the retina is derived entirely from the central retinal artery, unless a cilioretinal artery is present (Figure 1). (Cilioretinal arteries are found in about 35% of all eyes.) Retinal ischemia results from disease processes affecting the afferent vessels anywhere from the common carotid to the intraretinal arterioles. Signs and symptoms of arterial obstruction depend on the vessel involved. Occlusion of a peripheral extramacular arteriole may be asymptomatic, but ophthalmic artery occlusion can cause total blindness. Cholesterol emboli (Hollenhorst plaque) (Figure 2) from atherosclerotic disease is the leading cause of central retinal artery occlusion in patients over age 40 years. Emboli from the heart are the most common cause of central Kristine Wyatt practices at the Eye Institute in Tulsa, Okla. The author has disclosed no potential conflicts of interest, financial or otherwise. DOI: 10.1097/01.JAA.0000447004.96714.34 Copyright © 2014 American Academy of Physician Assistants
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retinal artery occlusion in patients under age 40 years. Rare causes include cardiac myxoma, fat emboli, septic emboli from infective endocarditis, talc emboli, migraine, trauma, coagulation disorders, sickle cell disease, oral contraceptive use, pregnancy, mitral valve prolapse, inflammations, infections, and connective tissue disorders.1 Morbidity and mortality Patients with visualized retinal artery emboli have 56% mortality over 9 years, compared with 27% for an age-matched population without retinal artery emboli. Life expectancy of patients with central retinal artery occlusion is 5.5 years compared with 15.4 years for an age-matched population without central retinal artery occlusion.2 Clinical presentation and examination findings Patients present with a sudden painless loss of unilateral vision. Occlusion of the central retinal artery will cause nearcomplete vision loss, but a branch arterial occlusion will cause a scotoma in the corresponding visual field.
Management of central retinal artery occlusion also is aimed at risk factors that may lead to other vascular conditions. In the first few hours after the occlusion, the fundus may appear normal, and visualizing the actual point of occlusion within the vessel may be difficult. Later, however, ischemia to the retinal tissue causes it to whiten. The classic “cherry red spot” is seen in occlusion of the central retinal artery because the macula receives its blood supply from the choroid, supplied by the posterior ciliary arteries, and the surrounding retina is pale. IV fluorescein angiography may reveal a delay in retinal arterial filling. The most commonly observed fluorescein angiographic sign, however, is an arteriovenous transit time greater than 11 seconds (Figures 3 and 4).3 Arteriovenous transit time is defined as the time from the appearance of contrast media within the temporal retinal arteries until the major veins in the temporal retinal vascular arcade are completely filled. Volume 27 • Number 6 • June 2014
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Three common ophthalmic emergencies
Key points Vision changes and ophthalmic complaints may represent potentially serious, sometimes fatal, systemic illnesses. Central retinal artery occlusion carries the same atherosclerotic risk factors as stroke and cardiac disease. Giant cell arteritis, a systemic inflammatory condition, can lead to blindness if not treated promptly. Oculomotor nerve palsy can be caused by an intracranial aneurysm or tumor.
Diagnostic evaluation A systemic workup should include: • complete blood cell (CBC) count to evaluate anemia, polycythemia, and platelet disorders • erythrocyte sedimentation rate (ESR) and C-reactive protein to evaluate for giant cell arteritis • fibrinogen, antiphospholipid antibodies, prothrombin time (PT), activated partial thromboplastin time (aPTT), and serum protein electrophoresis to evaluate for coagulopathies • fasting blood glucose, cholesterol, triglycerides, and lipid panel to evaluate for atherosclerotic disease
• blood cultures to evaluate for bacterial endocarditis and septic emboli.2 Treatment Studies in nonhuman primates have suggested that irreversible damage to the sensory retina occurs after 90 minutes of central retinal artery obstruction. Nevertheless, clinical return of vision can be seen in some instances even if the obstruction has persisted for many hours.4 Therapies that have been used to treat central retinal artery occlusion include carbogen inhalation, acetazolamide infusion, ocular massage, paracentesis, and IV vasodilators. None of these “standard agents” have been shown to definitively alter the natural history of disease.5 Because the risk factors for retinal artery occlusion are the same atherosclerotic risk factors as for stroke and heart disease, patients may be at risk for ischemic end-organ damage such as stroke. Therefore, management of central retinal artery occlusion is aimed not only at restoring vision, but at managing risk factors that may lead to other vascular conditions. GIANT CELL ARTERITIS A 73-year-old woman presents with a complaint of transient loss of vision in her right eye. She has noted similar
FIGURE 1. Ocular blood supply
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symptoms over the past 2 months, with resolution of symptoms after a few minutes. Her past medical history is significant for osteoarthritis, occasional headache, and mild gastroesophageal reflux disease. She has not had an eye examination for several years, but says that her last one was normal. She is a nonsmoker. She takes no prescribed medications, but does take a daily multivitamin and occasional ibuprofen and antacids. She denies trauma, flashes, or floaters. She states she had two episodes in the last 3 weeks of temporary loss of vision in the right eye, noting that each episode resolved completely after a minute or so. On further questioning, she complains of decreased appetite, occasional jaw claudication, and occasional scalp tenderness and pain around the right eye. On examination, her vision with correction is 20/25 in the right eye and 20/30 in the left. Pupils are equally round and reactive to light. Direct ophthalmoscopy reveals mild macular drusen. Pathophysiology Giant cell arteritis, also called temporal arteritis and cranial arteritis, is a systemic, inflammatory, vascular syndrome that predominantly affects the temporal arteries.6 In the late 19th century, Jonathan Hutchinson described a man who had difficulty wearing a hat because of his tender temporal arteries.7 In 1957, Barber described polymyalgia rheumatica (a condition that can overlap giant cell arteritis) as an aching syndrome that was not associated with other defined rheumatic, infectious, or neoplastic disorders and that usually occurred in older adults with constitutional symptoms and an elevated ESR.8 Although the cause of giant cell arteritis is unknown, the pathogenesis is a chronic inflammatory process involving predominantly large arteries and resulting in the elevation of various cytokines. Systemic manifestation is likely related to the inflammatory process and cytokine elevation; endorgan involvement is related to vascular occlusion.9
Morbidity and mortality Polymyalgia rheumatica affects about 1 per 1,000 persons older than age 50 years. The true incidence of giant cell arteritis is unknown, but researchers suggest that the rate in the United States ranges from 0.49 to 27.3 cases per 100,000 population among persons older than age 50 years.10 Clinical presentation Patients with three or more of the following criteria may have giant cell arteritis:11 • age 50 years or older • new-onset localized headache • temporal artery tenderness or decreased temporal artery pulse • ESR of at least 50 mm/hour • abnormal artery biopsy specimen characterized by mononuclear infiltration or granulomatous inflammation. The most commonly reported symptoms are headache (initial symptom in 33% of patients and present in 72%); neck, torso, shoulder, and pelvic girdle pain that is consis-
FIGURE 3. Central retinal artery occlusion
FIGURE 2. Hollenhorst plaque
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FIGURE 4. Central retinal artery occlusion on fluorescein
angiography Volume 27 • Number 6 • June 2014
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Three common ophthalmic emergencies
tent with polymyalgia rheumatica (initial symptom in 25% with signs and symptoms of giant cell arteritis, with or of patients and present in 58%); fatigue and malaise (ini- without amaurosis fugax. In patients with vision loss, IV tial symptom in 20% of patients and present in 56%); jaw methylprednisolone is preferred. claudication (initial symptom in 4% of patients and presSymptoms usually resolve quickly, often within 2 to 3 ent in 40%); and fever (initial symptom in 11% of patients days of starting corticosteroids. Most authorities recomand present in 35%).12 mend continuing the high dosage of prednisone until the Amaurosis fugax (“fleeting vision loss”) occurs in 10% ESR has declined to a normal level.16 This usually occurs to 12% of patients with giant cell arteritis. Permanent loss within 4 to 6 weeks. of vision due to anterior ischemic optic neuropathy occurs A retrospective analysis of patients (n=175) diagnosed in 8% to 23%. Before 1960, most studies reported that with giant cell arteritis between 1980 and 2000 showed patients with transient loss of vision went on to develop that the addition of daily low-dose aspirin decreased the permanent, bilateral loss of vision due to anterior ischemic incidence of cerebrovascular accidents and visual loss.17 optic neuropathy. Following monocular onset, the second eye became affected within days.12 OCULOMOTOR NERVE PALSY Diagnostic evaluation Laboratory studies are helpful in A 53-year-old woman presents with a complaint of a “lazy determining the cause of central retinal artery occlusion. eye” since yesterday. She says that her right eye is “hard • CBC count to evaluate anemia, polycythemia, and plateto open,” but otherwise has no vision complaints. Her let disorders past medical history is significant for hypothyroidism and • ESR and C-reactive protein evaluation for giant cell type 2 diabetes. She is a nonsmoker. She underwent sucarteritis. C-reactive protein was more sensitive (100%) cessful bilateral laser-assisted in situ keratomileusis (LASIK) than ESR (92%) for detecting giant cell arteritis, and ESR at age 41, and has had annual eye examinations with no plus C-reactive protein gave the best specificity (97%).13 abnormal findings since. Her daily medications include • Fibrinogen, antiphospholipid antibodies, PT/aPTT, and levothyroxine, metformin, and multivitamins. She denies serum protein electrophoresis to evaluate for coagulopathies eye or head trauma, eye pain, and vision changes. She • fasting blood glucose, cholesterol, triglycerides, and lipid notes a headache, described as constant and worsening panel to evaluate for atherosclerotic disease over the past 3 days. On examination, she has a full pto• blood cultures to evaluate for bacterial endocarditis and sis of the right eye. Lifting her lid reveals misalignment of septic emboli.2 the right globe. She has 20/20 vision, uncorrected, in each A superficial temporal artery biopsy will show focal eye. The right pupil is larger than the left and reacts poorly granulomatous arteritis, often with giant cells and patch to direct light. Pathophysiology The oculomotor nerve (the third cranial (“skip areas”) of normal arterial wall. Because of the nerve) supplies the levator muscle of the eyelid and four patchy involvement of the arteries, biopsies may be extraocular muscles: the medial rectus, superior rectus, nondiagnostic in many patients, and nondiagnostic inferior rectus, and inferior oblique. These muscles adduct, biopsy specimens do not exclude the diagnosis of giant cell arteritis. Some experts even suggest that biopsy may not be necessary.14 Color duplex ultrasonography of the temporal arteries is being investigated as a diagnostic tool for giant cell arteritis. The sensitivity and specificity of this technique may prove to be sufficiently high to obviate the need for biopsy in some patients.15 Treatment In patients with acute vision loss and a high suspicion of giant cell arteritis, begin corticosteroid therapy promptly; waiting for the results of a temporal artery biopsy puts the patient at risk for irreversible vision loss. Prednisone, usually starting at 40 to 60 mg/day, is the preferred therapy for patients FIGURE 5. Oculomotor nerve anatomy JAAPA Journal of the American Academy of Physician Assistants
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FIGURE 6. Full ptosis and dysmotility in oculomotor nerve palsy
COURTESY OF THE JOURNAL OF EMERGENCY MEDICINE 2008
depress, and elevate the eye. In addition, the third cranial nerve constricts the pupil through its parasympathetic fibers that supply the smooth muscle of the ciliary body and the sphincter of the iris. Oculomotor nerve palsies can cause dysfunction of the somatic and autonomic muscles. Patients with a complete oculomotor nerve palsy present with ptosis and an inability to adduct, supraduct, or infraduct the involved eye. The pupil is dilated and responds poorly to light (Figure 5). Partial oculomotor nerve palsies present with variable ptosis, movement limitation, and pupillary involvement.18 Most isolated unilateral oculomotor nerve palsies result from presumed microvascular injury in the subarachnoid space or cavernous sinus. Isolated oculomotor nerve palsies may also occur due to brainstem lesions, such as microvascular infarct. Less common causes include aneurysmal compression, tumor, inflammation, vasculitis (sarcoidosis), infection (meningitis), infiltration (lymphoma, carcinoma), and trauma. Children may develop transient ophthalmoplegias following a viral illness or vaccination. A discussion of pediatric oculomotor nerve palsy is beyond the scope of this article.
FIGURE 7. Posterior communicating artery and cranial nerve III
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Clinical presentation The presentation of oculomotor nerve palsy is extremely varied, so the clinician must think of this possibility when patients have complaints relating to the eye. Patients may have diplopia, ptosis, eye pain, headache, pupillary dilatation, monocular blurry vision, or any combination of these signs and symptoms. Oculomotor nerve palsies can be classified as pupil-involving or pupilsparing as well as by the degree of extraocular muscle dysfunction (partial or complete). The pupillary distinction is important because the pupil is almost always involved when an aneurysm or other compressive lesion is the cause of oculomotor nerve palsy; this has become known as “the rule of the pupil.”19,20 In pupil-sparing oculomotor nerve palsy, the patient has normal pupillary function, but complete loss of somatic (lid and oculomotor) function. This is the typical finding of an ischemic cranial neuropathy, which is often painful, and is usually fully resolved within 3 months.21 This disorder is almost always benign and secondary to microvascular disease, often associated with diabetes, hypertension, or hyperlipidema. A partial oculomotor nerve palsy presents with a normally reacting pupil and only minimal impairment of somatic function. However, although the pupil is normal in this scenario, it should not be considered in the same category as pupil-sparing with complete oculomotor paresis, given that many other fibers within the third cranial nerve were also spared. A pupil-involving oculomotor nerve palsy results from a loss of parasympathetic input. The pupil responds poorly to light, and the patient has a wide range of dysfunction in the levator palpebrae and extraocular muscle (Figure 6). Aneurysms arising from the junction of the posterior communicating and internal carotid arteries are juxtaposed to the third cranial nerve and are, therefore, in a position to produce an oculomotor nerve palsy with pupillary involvement as the initial manifestation of an aneurysm expansion or rupture (Figure 7).22 The flowsheet (Figure 8) outlines the steps involved in identifying the cause of an oculomotor nerve palsy. Management The location of the causative lesion and the underlying cause guide management of oculomotor nerve palsy. • Medical management for a patient with a pupil-sparing complete oculomotor palsy is actually watchful waiting because no direct medical treatment can alter the course of the Volume 27 • Number 6 • June 2014
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disease. Fortunately, nearly all patients ISOLATED 3RD NERVE PARALYSIS undergo spontaneous remission within 6 to 8 weeks. Pupil spared Pupil involved • Management of a pupil-sparing partial oculomotor nerve palsy must be individualized based on the demographics, history, Pupil involved Trauma Aneurysm days later and availability of noninvasive imaging modalities. Some clinicians favor noninTumor MRI vasive imaging; others advocate daily Arteriogram Tumor Progressive signs observation for 7 to 10 days. Suspect an aneurysm even with a seemingly benign Cavernous sinus If negative pupil-sparing oculomotor nerve palsy if (less often Cavernous sinus Diabetes Subdural orbit) orbit with and the patient is within the high-risk age range HVD Meningitis without orbital Stroke for developing an aneurysm (ages 20 to Brain abscess signs Tolosa-Hum 50 years) and does not have diabetes or Vasculopathy Herpes zoster other vascular risk factors.18 Migraine Temporal arteritis • A nontraumatic pupil-involving ocuAmyloidosis lomotor nerve palsy (or one with eviDiabetes Multiple sclerosis AIDS dence of progression to pupillary involvement) must be assumed to be caused by an aneurysm until proven FIGURE 8. Determining the cause of oculomotor nerve palsy otherwise. Obtain a prompt neuroophthalmologic consultation and angiography. Despite 11. Hunder GG, Bloch DA, Michel BA, et al. The American College of Rheumatology 1990 criteria for the classification of giant cell advances in noninvasive neuroimaging techniques, arteritis. Arthritis Rheum. 1990;33(8):1122-1128. catheter angiography remains the gold standard in 12. Ramachandran T. Temporal/giant cell arteritis. http://emedicine. detecting intracranial aneurysms. medscape.com/article/1147184-overview. Accessed November Vision symptoms can be indicators of serious, potentially 24, 2013. fatal, systemic conditions. By understanding these three 13. Hayreh SS, Podhajsky PA, Raman R, Zimmerman B. Giant cell ophthalmic emergencies and their links to potentially seriarteritis: validity and reliability of various diagnostic criteria. Am J Ophthamoll. 1997;123(3):285-296. ous underlying causes, you can provide your patient with 14. Pountain G, Hazleman B. ABC of rheumatology. Polymyalgia prompt, appropriate care. JAAPA rheumatica and giant cell arteritis. BMJ. 1995;310(6986):10571059.
REFERENCES 1. Arruga J, Sanders MD. Ophthalmologic findings in 70 patients with evidence of retinal embolism. Ophthalmology. 1982;89 (12):1336-1347. 2. Graham R. Central retinal artery occlusion. http://emedicine. medscape.com/article/1223625-overview. Accessed November 1, 2013. 3. Williamson Eye Institute. Retinal artery occlusions. http://www. williamsoneyeinstitute.com. Accessed November 1, 2013. 4. Hayreh SS, Kolder HE, Weingeist TA. Central retinal artery occlusion and retinal tolerance time. Ophthalmology. 1980;87 (1):75-78. 5. Atebara NH, Brown GC, Cater J. Efficacy of anterior chamber paracentesis and carbogen in treating acute nonarteritic central retinal artery occlusion. Ophthalmology. 1995;102(12):2029-2034. 6. Hunder GG. The early history of giant cell arteritis and polymyalgia rheumatica: first descriptions to 1970. Mayo Clin Proc. 2006;81(8):1071-1083. 7. Online Mendelian Inheritance in Man. Temporal arteritis. http:// omim.org/entry/187360. Accessed November 1, 2013. 8. Barber HS. Myalgic syndrome with constitutional effects; polymyalgia rheumatica. Ann Rheum Dis. 1957;16(2):230-237. 9. Mythili S. Giant cell arteritis. http://emedicine.medscape.com/ article/332483-overview. Accessed November 1, 2013. 10. Goodwin JS. Progress in gerontology: polymyalgia rheumatica and temporal arteritis. J Am Geriatr Soc. 1992;40(5):515-525.
15. Schmidt WA, Kraft HE, Vorpahl K, et al. Color duplex ultrasonography in the diagnosis of temporal arteritis. N Engl J Med. 1997;337(19):1336-1342. 16. Hellmann DB. Giant cell arteritis and polymyalgia rheumatic. In Firestein GS, Budd RC, Harris ED Jr, et al. Kelley’s Textbook of Rheumatology. 8th ed. Philadelphia, PA: W.B. Saunders, Inc.; 2008. 17. Nesher G, Berkun Y, Mates M, et al. Low-dose aspirin and prevention of cranial ischemic complications in giant cell arteritis. Arthritis Rheum. 2004;50(4):1332-1337. 18. American Academy of Ophthalmology. Neuro-ophthalmology. In: Basic and Clinical Science Course. The Foundation of the American Academy of Ophthalmology; 2009-2010:228-230. 19. Green WR, Hackett ER, Schlezinger NS. Neuro-ophthalmologic evaluation of oculomotor nerve paralysis. Arch Ophthalmol. 1964;72:154-167. 20. Kerr FW, Hollowell OW. Location of pupillomotor and accommodation fibres in the oculomotor nerve: experimental observations on paralytic mydriasis. J Neurol Neurosurg Psychiatry. 1964;27:473-481. 21. Cranial nerve III palsy. In: Sowka JW, Gurwood AS, Kabat AG, eds. Handbook of Ocular Disease Management. http://cms. revoptom.com/handbook/sect6c.htm. Jobson Publishing; 2001. 22. Jacobson DM. Relative pupil-sparing third nerve palsy: etiology and clinical variables predictive of a mass. Neurology. 2001;56 (6):797-798.
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Three common ophthalmic emergencies
Three common ophthalmic emergencies Kristine Wyatt, PA-C
ABSTRACT Vision changes and ophthalmic complaints may represent potentially serious, sometimes fatal, systemic illnesses. This article summarizes the presenting signs and symptoms of retinal artery occlusion, giant cell arteritis, and oculomotor nerve palsy. Keywords: retinal artery occlusion, giant cell arteritis, amaurosis fugax, oculomotor nerve palsy, communicating artery aneurysm, ophthalmic emergencies
ARTERIAL OCCLUSIVE DISEASE A 66-year-old man presents with a complaint of a change in vision in his right eye. He describes a “blank spot” in his peripheral vision, which he first noted upon waking this morning. His past medical history is significant for mild hypertension and hypercholesterolemia. He has been diagnosed with bilateral mild cataracts. His prescribed medications are 81-mg aspirin, hydrochlorothiazide, pravastatin, and vitamins. He denies trauma, pain, flashes, floaters, headaches, jaw claudication, scalp tenderness, weight loss, and loss of appetite. On examination, he has corrected vision of 20/25 in each eye, and his pupils are equally round and reactive to light. Confrontation field testing shows a scotoma infero-temporally in the right eye, but intact peripheral vision in the left eye. Direct ophthalmoscopy is unremarkable. Pathophysiology The blood supply to the inner layers of the retina is derived entirely from the central retinal artery, unless a cilioretinal artery is present (Figure 1). (Cilioretinal arteries are found in about 35% of all eyes.) Retinal ischemia results from disease processes affecting the afferent vessels anywhere from the common carotid to the intraretinal arterioles. Signs and symptoms of arterial obstruction depend on the vessel involved. Occlusion of a peripheral extramacular arteriole may be asymptomatic, but ophthalmic artery occlusion can cause total blindness. Cholesterol emboli (Hollenhorst plaque) (Figure 2) from atherosclerotic disease is the leading cause of central retinal artery occlusion in patients over age 40 years. Emboli from the heart are the most common cause of central Kristine Wyatt practices at the Eye Institute in Tulsa, Okla. The author has disclosed no potential conflicts of interest, financial or otherwise. DOI: 10.1097/01.JAA.0000447004.96714.34 Copyright © 2014 American Academy of Physician Assistants
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retinal artery occlusion in patients under age 40 years. Rare causes include cardiac myxoma, fat emboli, septic emboli from infective endocarditis, talc emboli, migraine, trauma, coagulation disorders, sickle cell disease, oral contraceptive use, pregnancy, mitral valve prolapse, inflammations, infections, and connective tissue disorders.1 Morbidity and mortality Patients with visualized retinal artery emboli have 56% mortality over 9 years, compared with 27% for an age-matched population without retinal artery emboli. Life expectancy of patients with central retinal artery occlusion is 5.5 years compared with 15.4 years for an age-matched population without central retinal artery occlusion.2 Clinical presentation and examination findings Patients present with a sudden painless loss of unilateral vision. Occlusion of the central retinal artery will cause nearcomplete vision loss, but a branch arterial occlusion will cause a scotoma in the corresponding visual field.
Management of central retinal artery occlusion also is aimed at risk factors that may lead to other vascular conditions. In the first few hours after the occlusion, the fundus may appear normal, and visualizing the actual point of occlusion within the vessel may be difficult. Later, however, ischemia to the retinal tissue causes it to whiten. The classic “cherry red spot” is seen in occlusion of the central retinal artery because the macula receives its blood supply from the choroid, supplied by the posterior ciliary arteries, and the surrounding retina is pale. IV fluorescein angiography may reveal a delay in retinal arterial filling. The most commonly observed fluorescein angiographic sign, however, is an arteriovenous transit time greater than 11 seconds (Figures 3 and 4).3 Arteriovenous transit time is defined as the time from the appearance of contrast media within the temporal retinal arteries until the major veins in the temporal retinal vascular arcade are completely filled. Volume 27 • Number 6 • June 2014
Copyright © 2014 Lippincott Williams & Wilkins. Unauthorized reproduction of this article is prohibited.
Three common ophthalmic emergencies
Key points Vision changes and ophthalmic complaints may represent potentially serious, sometimes fatal, systemic illnesses. Central retinal artery occlusion carries the same atherosclerotic risk factors as stroke and cardiac disease. Giant cell arteritis, a systemic inflammatory condition, can lead to blindness if not treated promptly. Oculomotor nerve palsy can be caused by an intracranial aneurysm or tumor.
Diagnostic evaluation A systemic workup should include: • complete blood cell (CBC) count to evaluate anemia, polycythemia, and platelet disorders • erythrocyte sedimentation rate (ESR) and C-reactive protein to evaluate for giant cell arteritis • fibrinogen, antiphospholipid antibodies, prothrombin time (PT), activated partial thromboplastin time (aPTT), and serum protein electrophoresis to evaluate for coagulopathies • fasting blood glucose, cholesterol, triglycerides, and lipid panel to evaluate for atherosclerotic disease
• blood cultures to evaluate for bacterial endocarditis and septic emboli.2 Treatment Studies in nonhuman primates have suggested that irreversible damage to the sensory retina occurs after 90 minutes of central retinal artery obstruction. Nevertheless, clinical return of vision can be seen in some instances even if the obstruction has persisted for many hours.4 Therapies that have been used to treat central retinal artery occlusion include carbogen inhalation, acetazolamide infusion, ocular massage, paracentesis, and IV vasodilators. None of these “standard agents” have been shown to definitively alter the natural history of disease.5 Because the risk factors for retinal artery occlusion are the same atherosclerotic risk factors as for stroke and heart disease, patients may be at risk for ischemic end-organ damage such as stroke. Therefore, management of central retinal artery occlusion is aimed not only at restoring vision, but at managing risk factors that may lead to other vascular conditions. GIANT CELL ARTERITIS A 73-year-old woman presents with a complaint of transient loss of vision in her right eye. She has noted similar
FIGURE 1. Ocular blood supply
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symptoms over the past 2 months, with resolution of symptoms after a few minutes. Her past medical history is significant for osteoarthritis, occasional headache, and mild gastroesophageal reflux disease. She has not had an eye examination for several years, but says that her last one was normal. She is a nonsmoker. She takes no prescribed medications, but does take a daily multivitamin and occasional ibuprofen and antacids. She denies trauma, flashes, or floaters. She states she had two episodes in the last 3 weeks of temporary loss of vision in the right eye, noting that each episode resolved completely after a minute or so. On further questioning, she complains of decreased appetite, occasional jaw claudication, and occasional scalp tenderness and pain around the right eye. On examination, her vision with correction is 20/25 in the right eye and 20/30 in the left. Pupils are equally round and reactive to light. Direct ophthalmoscopy reveals mild macular drusen. Pathophysiology Giant cell arteritis, also called temporal arteritis and cranial arteritis, is a systemic, inflammatory, vascular syndrome that predominantly affects the temporal arteries.6 In the late 19th century, Jonathan Hutchinson described a man who had difficulty wearing a hat because of his tender temporal arteries.7 In 1957, Barber described polymyalgia rheumatica (a condition that can overlap giant cell arteritis) as an aching syndrome that was not associated with other defined rheumatic, infectious, or neoplastic disorders and that usually occurred in older adults with constitutional symptoms and an elevated ESR.8 Although the cause of giant cell arteritis is unknown, the pathogenesis is a chronic inflammatory process involving predominantly large arteries and resulting in the elevation of various cytokines. Systemic manifestation is likely related to the inflammatory process and cytokine elevation; endorgan involvement is related to vascular occlusion.9
Morbidity and mortality Polymyalgia rheumatica affects about 1 per 1,000 persons older than age 50 years. The true incidence of giant cell arteritis is unknown, but researchers suggest that the rate in the United States ranges from 0.49 to 27.3 cases per 100,000 population among persons older than age 50 years.10 Clinical presentation Patients with three or more of the following criteria may have giant cell arteritis:11 • age 50 years or older • new-onset localized headache • temporal artery tenderness or decreased temporal artery pulse • ESR of at least 50 mm/hour • abnormal artery biopsy specimen characterized by mononuclear infiltration or granulomatous inflammation. The most commonly reported symptoms are headache (initial symptom in 33% of patients and present in 72%); neck, torso, shoulder, and pelvic girdle pain that is consis-
FIGURE 3. Central retinal artery occlusion
FIGURE 2. Hollenhorst plaque
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FIGURE 4. Central retinal artery occlusion on fluorescein
angiography Volume 27 • Number 6 • June 2014
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Three common ophthalmic emergencies
tent with polymyalgia rheumatica (initial symptom in 25% with signs and symptoms of giant cell arteritis, with or of patients and present in 58%); fatigue and malaise (ini- without amaurosis fugax. In patients with vision loss, IV tial symptom in 20% of patients and present in 56%); jaw methylprednisolone is preferred. claudication (initial symptom in 4% of patients and presSymptoms usually resolve quickly, often within 2 to 3 ent in 40%); and fever (initial symptom in 11% of patients days of starting corticosteroids. Most authorities recomand present in 35%).12 mend continuing the high dosage of prednisone until the Amaurosis fugax (“fleeting vision loss”) occurs in 10% ESR has declined to a normal level.16 This usually occurs to 12% of patients with giant cell arteritis. Permanent loss within 4 to 6 weeks. of vision due to anterior ischemic optic neuropathy occurs A retrospective analysis of patients (n=175) diagnosed in 8% to 23%. Before 1960, most studies reported that with giant cell arteritis between 1980 and 2000 showed patients with transient loss of vision went on to develop that the addition of daily low-dose aspirin decreased the permanent, bilateral loss of vision due to anterior ischemic incidence of cerebrovascular accidents and visual loss.17 optic neuropathy. Following monocular onset, the second eye became affected within days.12 OCULOMOTOR NERVE PALSY Diagnostic evaluation Laboratory studies are helpful in A 53-year-old woman presents with a complaint of a “lazy determining the cause of central retinal artery occlusion. eye” since yesterday. She says that her right eye is “hard • CBC count to evaluate anemia, polycythemia, and plateto open,” but otherwise has no vision complaints. Her let disorders past medical history is significant for hypothyroidism and • ESR and C-reactive protein evaluation for giant cell type 2 diabetes. She is a nonsmoker. She underwent sucarteritis. C-reactive protein was more sensitive (100%) cessful bilateral laser-assisted in situ keratomileusis (LASIK) than ESR (92%) for detecting giant cell arteritis, and ESR at age 41, and has had annual eye examinations with no plus C-reactive protein gave the best specificity (97%).13 abnormal findings since. Her daily medications include • Fibrinogen, antiphospholipid antibodies, PT/aPTT, and levothyroxine, metformin, and multivitamins. She denies serum protein electrophoresis to evaluate for coagulopathies eye or head trauma, eye pain, and vision changes. She • fasting blood glucose, cholesterol, triglycerides, and lipid notes a headache, described as constant and worsening panel to evaluate for atherosclerotic disease over the past 3 days. On examination, she has a full pto• blood cultures to evaluate for bacterial endocarditis and sis of the right eye. Lifting her lid reveals misalignment of septic emboli.2 the right globe. She has 20/20 vision, uncorrected, in each A superficial temporal artery biopsy will show focal eye. The right pupil is larger than the left and reacts poorly granulomatous arteritis, often with giant cells and patch to direct light. Pathophysiology The oculomotor nerve (the third cranial (“skip areas”) of normal arterial wall. Because of the nerve) supplies the levator muscle of the eyelid and four patchy involvement of the arteries, biopsies may be extraocular muscles: the medial rectus, superior rectus, nondiagnostic in many patients, and nondiagnostic inferior rectus, and inferior oblique. These muscles adduct, biopsy specimens do not exclude the diagnosis of giant cell arteritis. Some experts even suggest that biopsy may not be necessary.14 Color duplex ultrasonography of the temporal arteries is being investigated as a diagnostic tool for giant cell arteritis. The sensitivity and specificity of this technique may prove to be sufficiently high to obviate the need for biopsy in some patients.15 Treatment In patients with acute vision loss and a high suspicion of giant cell arteritis, begin corticosteroid therapy promptly; waiting for the results of a temporal artery biopsy puts the patient at risk for irreversible vision loss. Prednisone, usually starting at 40 to 60 mg/day, is the preferred therapy for patients FIGURE 5. Oculomotor nerve anatomy JAAPA Journal of the American Academy of Physician Assistants
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FIGURE 6. Full ptosis and dysmotility in oculomotor nerve palsy
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depress, and elevate the eye. In addition, the third cranial nerve constricts the pupil through its parasympathetic fibers that supply the smooth muscle of the ciliary body and the sphincter of the iris. Oculomotor nerve palsies can cause dysfunction of the somatic and autonomic muscles. Patients with a complete oculomotor nerve palsy present with ptosis and an inability to adduct, supraduct, or infraduct the involved eye. The pupil is dilated and responds poorly to light (Figure 5). Partial oculomotor nerve palsies present with variable ptosis, movement limitation, and pupillary involvement.18 Most isolated unilateral oculomotor nerve palsies result from presumed microvascular injury in the subarachnoid space or cavernous sinus. Isolated oculomotor nerve palsies may also occur due to brainstem lesions, such as microvascular infarct. Less common causes include aneurysmal compression, tumor, inflammation, vasculitis (sarcoidosis), infection (meningitis), infiltration (lymphoma, carcinoma), and trauma. Children may develop transient ophthalmoplegias following a viral illness or vaccination. A discussion of pediatric oculomotor nerve palsy is beyond the scope of this article.
FIGURE 7. Posterior communicating artery and cranial nerve III
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Clinical presentation The presentation of oculomotor nerve palsy is extremely varied, so the clinician must think of this possibility when patients have complaints relating to the eye. Patients may have diplopia, ptosis, eye pain, headache, pupillary dilatation, monocular blurry vision, or any combination of these signs and symptoms. Oculomotor nerve palsies can be classified as pupil-involving or pupilsparing as well as by the degree of extraocular muscle dysfunction (partial or complete). The pupillary distinction is important because the pupil is almost always involved when an aneurysm or other compressive lesion is the cause of oculomotor nerve palsy; this has become known as “the rule of the pupil.”19,20 In pupil-sparing oculomotor nerve palsy, the patient has normal pupillary function, but complete loss of somatic (lid and oculomotor) function. This is the typical finding of an ischemic cranial neuropathy, which is often painful, and is usually fully resolved within 3 months.21 This disorder is almost always benign and secondary to microvascular disease, often associated with diabetes, hypertension, or hyperlipidema. A partial oculomotor nerve palsy presents with a normally reacting pupil and only minimal impairment of somatic function. However, although the pupil is normal in this scenario, it should not be considered in the same category as pupil-sparing with complete oculomotor paresis, given that many other fibers within the third cranial nerve were also spared. A pupil-involving oculomotor nerve palsy results from a loss of parasympathetic input. The pupil responds poorly to light, and the patient has a wide range of dysfunction in the levator palpebrae and extraocular muscle (Figure 6). Aneurysms arising from the junction of the posterior communicating and internal carotid arteries are juxtaposed to the third cranial nerve and are, therefore, in a position to produce an oculomotor nerve palsy with pupillary involvement as the initial manifestation of an aneurysm expansion or rupture (Figure 7).22 The flowsheet (Figure 8) outlines the steps involved in identifying the cause of an oculomotor nerve palsy. Management The location of the causative lesion and the underlying cause guide management of oculomotor nerve palsy. • Medical management for a patient with a pupil-sparing complete oculomotor palsy is actually watchful waiting because no direct medical treatment can alter the course of the Volume 27 • Number 6 • June 2014
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disease. Fortunately, nearly all patients ISOLATED 3RD NERVE PARALYSIS undergo spontaneous remission within 6 to 8 weeks. Pupil spared Pupil involved • Management of a pupil-sparing partial oculomotor nerve palsy must be individualized based on the demographics, history, Pupil involved Trauma Aneurysm days later and availability of noninvasive imaging modalities. Some clinicians favor noninTumor MRI vasive imaging; others advocate daily Arteriogram Tumor Progressive signs observation for 7 to 10 days. Suspect an aneurysm even with a seemingly benign Cavernous sinus If negative pupil-sparing oculomotor nerve palsy if (less often Cavernous sinus Diabetes Subdural orbit) orbit with and the patient is within the high-risk age range HVD Meningitis without orbital Stroke for developing an aneurysm (ages 20 to Brain abscess signs Tolosa-Hum 50 years) and does not have diabetes or Vasculopathy Herpes zoster other vascular risk factors.18 Migraine Temporal arteritis • A nontraumatic pupil-involving ocuAmyloidosis lomotor nerve palsy (or one with eviDiabetes Multiple sclerosis AIDS dence of progression to pupillary involvement) must be assumed to be caused by an aneurysm until proven FIGURE 8. Determining the cause of oculomotor nerve palsy otherwise. Obtain a prompt neuroophthalmologic consultation and angiography. Despite 11. Hunder GG, Bloch DA, Michel BA, et al. The American College of Rheumatology 1990 criteria for the classification of giant cell advances in noninvasive neuroimaging techniques, arteritis. Arthritis Rheum. 1990;33(8):1122-1128. catheter angiography remains the gold standard in 12. Ramachandran T. Temporal/giant cell arteritis. http://emedicine. detecting intracranial aneurysms. medscape.com/article/1147184-overview. Accessed November Vision symptoms can be indicators of serious, potentially 24, 2013. fatal, systemic conditions. By understanding these three 13. Hayreh SS, Podhajsky PA, Raman R, Zimmerman B. Giant cell ophthalmic emergencies and their links to potentially seriarteritis: validity and reliability of various diagnostic criteria. Am J Ophthamoll. 1997;123(3):285-296. ous underlying causes, you can provide your patient with 14. Pountain G, Hazleman B. ABC of rheumatology. Polymyalgia prompt, appropriate care. JAAPA rheumatica and giant cell arteritis. BMJ. 1995;310(6986):10571059.
REFERENCES 1. Arruga J, Sanders MD. Ophthalmologic findings in 70 patients with evidence of retinal embolism. Ophthalmology. 1982;89 (12):1336-1347. 2. Graham R. Central retinal artery occlusion. http://emedicine. medscape.com/article/1223625-overview. Accessed November 1, 2013. 3. Williamson Eye Institute. Retinal artery occlusions. http://www. williamsoneyeinstitute.com. Accessed November 1, 2013. 4. Hayreh SS, Kolder HE, Weingeist TA. Central retinal artery occlusion and retinal tolerance time. Ophthalmology. 1980;87 (1):75-78. 5. Atebara NH, Brown GC, Cater J. Efficacy of anterior chamber paracentesis and carbogen in treating acute nonarteritic central retinal artery occlusion. Ophthalmology. 1995;102(12):2029-2034. 6. Hunder GG. The early history of giant cell arteritis and polymyalgia rheumatica: first descriptions to 1970. Mayo Clin Proc. 2006;81(8):1071-1083. 7. Online Mendelian Inheritance in Man. Temporal arteritis. http:// omim.org/entry/187360. Accessed November 1, 2013. 8. Barber HS. Myalgic syndrome with constitutional effects; polymyalgia rheumatica. Ann Rheum Dis. 1957;16(2):230-237. 9. Mythili S. Giant cell arteritis. http://emedicine.medscape.com/ article/332483-overview. Accessed November 1, 2013. 10. Goodwin JS. Progress in gerontology: polymyalgia rheumatica and temporal arteritis. J Am Geriatr Soc. 1992;40(5):515-525.
15. Schmidt WA, Kraft HE, Vorpahl K, et al. Color duplex ultrasonography in the diagnosis of temporal arteritis. N Engl J Med. 1997;337(19):1336-1342. 16. Hellmann DB. Giant cell arteritis and polymyalgia rheumatic. In Firestein GS, Budd RC, Harris ED Jr, et al. Kelley’s Textbook of Rheumatology. 8th ed. Philadelphia, PA: W.B. Saunders, Inc.; 2008. 17. Nesher G, Berkun Y, Mates M, et al. Low-dose aspirin and prevention of cranial ischemic complications in giant cell arteritis. Arthritis Rheum. 2004;50(4):1332-1337. 18. American Academy of Ophthalmology. Neuro-ophthalmology. In: Basic and Clinical Science Course. The Foundation of the American Academy of Ophthalmology; 2009-2010:228-230. 19. Green WR, Hackett ER, Schlezinger NS. Neuro-ophthalmologic evaluation of oculomotor nerve paralysis. Arch Ophthalmol. 1964;72:154-167. 20. Kerr FW, Hollowell OW. Location of pupillomotor and accommodation fibres in the oculomotor nerve: experimental observations on paralytic mydriasis. J Neurol Neurosurg Psychiatry. 1964;27:473-481. 21. Cranial nerve III palsy. In: Sowka JW, Gurwood AS, Kabat AG, eds. Handbook of Ocular Disease Management. http://cms. revoptom.com/handbook/sect6c.htm. Jobson Publishing; 2001. 22. Jacobson DM. Relative pupil-sparing third nerve palsy: etiology and clinical variables predictive of a mass. Neurology. 2001;56 (6):797-798.
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Three common ophthalmic emergencies
