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Show Journal of Clinical Neuro- ophthalmology 10( 4): 244-- 247, 1990. © 1990 Raven Press' , New York Anterior Ischemic Optic Neuropathy Associated with Macrocytic Anemia Karl C. Golnik, M. D., and Steven A. Newman, M. D. A 37- year- old man experienced the acute onset of blurred vision, particularly in the inferior hemifield of his left eye. Neuro- ophthalmic examination showed a left afferent pupillary defect, a left inferior altitudinal visual field deficit, bilateral nerve fiber layer infarcts and hemorrhages, and left optic disc elevation with edema of the nerve fiber bundle. Complete examination and laboratory studies revealed only a severe folate deficiency anemia. This is the first well- documented report of anterior ischemic optic neuropathy associated with anemia in the absence of other systemic abnormalities. Key Words: Anterior ischemic optic neuropathyMacrocytic anemia. From the University of Virginia, Department of Ophthalmology, Charlottesville, Virginia, U. S. A. Presented at the North American Neuro- ophthalmology Society meeting, Cancun, Mexico, March 1989. Address correspondence and reprint requests to Dr. Steven A. Newman, Department of Ophthalmology, UVA Health Sciences Center, Box 475, Charlottesville, VA 22908, U. S. A. 244 Ocular abnormalities associated with anemia have been well described. Of these, anemic retinopathy is most common. Signs include venous dilatation, hard exudates, nerve fiber layer hemorrhage, white centered hemorrhages, and cytoid bodies ( nerve fiber layer infarcts) ( 1- 4). Numerous cases of optic neuropathy associated with anemia secondary to hemorrhage have been reported ( 59). Indeed, visual loss following hemorrhage has been recognized since Hippocrates ( 8). However, classic anterior ischemic optic neuropathy ( AlaN) associated solely with macrocytic anemia has rarely, if ever, been reported. We describe a patient with folate deficiency anemia who developed AlaN in the absence of other contributory factors. CASE REPORT A 37- year- old right- handed black man presented in October 1988 with a several week history of weakness, lethargy, and weight loss followed by the acute onset of photopsia and " blurred vision" in the left eye. The patient noted that objects were more difficult to see in the lower half of his visual field. He had an ocular history of myopia corrected for 30 years. Past medical history included ethanol abuse, distant abdominal trauma, and a recent flare of chronic right ankle osteomyelitis. A one year earl~ er eV~ luation for intermittent microscopic hematuna, With blood cultures and echocardiogram, had failed to determine a cause. There was no past surgical history, and the family history was noncontributory. On exar. ninatio~ 1 best corrected visual acuity was 20/ 20 m the nght eye and 20/ 60 in the left eye (- 6.00 + .50 x 105 R. E.; - 5.25 + 1.00 x 15 L. E.). T~ ere was a 3 log unit left afferent pupillary defect With concomitant subjective desaturation. Automated static perimetry ( Humphrey Program 24- 2) showed early arcuate changes on the right ( Fig. OPTIC NEUROPATHY AND ANEMIA 245 1A), and a dense inferior altitudinal field defect on the left ( Fig. 18). Applanation tensions were 17 on the right and 16 on the left. Motility, slit lamp, and gonioscopic examinations were normal. Ophthalmoscopy revealed multiple bilateral, peripapillary nerve fiber layer infarcts, venous dilatation and tortuosity, and white- centered blot hemorrhages. The left optic disc was elevated and the peripapillary nerve fiber layer was edematous ( Fig. 2). Fluorescein angiography showed normal choroidal and central retinal artery filling with leakage, and late staining of the left disc. General medical examination revealed heart rate, 110; respiratory rate, 24; blood pressure, 110/ 70 without orthostatic changes. His right ankle was mildly erythematous and hyperpigmented, but without effusion. Rectal exam was Hemocult negative. Laboratory analysis included hematocrit, 13.9% ( Hgb, 4.5) with a mean corpuscular volume of 125; corrected reticulocyte count, 0.5%; and a folate level of 0.9 ng/ ml ( normal > 1.8 ng/ ml). Peripheral blood smear showed oval macrocytes, metamyelocytes, and occasional nucleated red blood cells. Platelets, white blood cell count, electrolytes, vitamin B l2, and serum and urine protein electrophoresis were all within normal limits. Additional evaluation included electrocardiogram, chest roentgenogram, echocardiogram, and cranial computed axial tomography, none of which were abnormal. Empiric folate replacement therapy was begun, and by day 6 the corrected reticulocyte count had increased to 19%. Visual acuity improved to 20/ 30 but the left afferent pupillary defect persisted. Over 6 weeks the retinopathy com- A . · ' tt:~: j:! i:!,!:!~ i,.; ii j: Ii:: 1: ill:':: .,::.-:~~:~~ ;;;~;;;; ;;; ~ ~~~;~;;~ ~ ~ ."" ~ I ••• pO - • - • :. - .. e •• ' 1'" I · · · · --_. ::.:... ~.,: : :: ::: :: :: ~ : : .::.::. ~.,: : ~ : : ~ ~ : pletely resolved, optic atrophy developed, and the field defect and afferent pupillary defect remained unchanged. DISCUSSION Our patient had a severe macrocytic anemia associated with ocular findings, including decreased visual acuity, afferent pupillary defect, arcuate/ altitudinal visual field deficit, and hemorrhagic retinopathy. The retinal abnormalities were characteristic of anemic retinopathy. The reported incidence of retinopathy in macrocytic anemia varies from 33 to 90% ( 1- 4). Several investigators report a possible association between retinopathy and thrombocytopenia ( 1,3,4), although another more recent study controlled for systemic disease and did not ( 2). Our patient did not have thrombocytopenia, and his retinopathy resolved as the hematocrit increased. Pathogenesis of anemic retinopathy is probably related to capillary ischemia with secondary alterations in vascular integrity ( 10). A recent study, however, found no relationship between severity of anemia and incidence of retinopathy ( 2). In addition to the retinopathy, our patient had the classic findings of AlaN: the acute onset of an altitudinal visual field deficit and optic disc elevation with nerve fiber bundle edema. Pathogenesis of AlaN theoretically involves interference with the posterior ciliary artery blood supply to the prelaminar optic nerve ( 11). This ischemia may occur through two basic mechanisms: decreased blood delivery or increased resistance to blood flow. + FIG. 1. A: Early arcuate changes. B: A dense inferior altitudinal field defect was present. / elin Neuro- ophthalmol, Vol. 10, No. 4, 1990 246 K. C. GOLNIK AND S. A. NEWMAN A B FIG. 2. Peripapillary nerve fiber layer infarcts, retinal hemorrhages, venous dilatation, and tortuosity were present in both eyes. Note left disc edema ( A). Blood delivery may be compromised by severe systemic hypotension ( hemorrhage, surgery) or by vascular disease ( carotid artery stenosis). Alternatively, resistance to blood flow may be increased by local vascular disease ( arteritis, arteriosclerosis) or by increased intraocular pressure ( acute angle closure glaucoma) ( 12). AlaN associated with anemia is most often reported following hemorrhage ( 8), although cases subsequent to surgery ( 13) and hemodialysis ( 14) have been recognized. When documented, these cases involve an episode of hypotension, although visual complaints and decreased blood pressure are not necessarily temporally linked. Many pathogenic theories of AlaN following hemorrhage have been proposed. Alteration in oxygen delivery due to a combination of anemia and hypotension is most commonly postulated. However, as Hayreh ( 1987) pointed out, AlaN can occur days after hemorrhage when the hematocrit is normal ( 8). To explain this apparent temporal disparity, he cited the increased angiotensin levels observed after experimentally induced hemorrhage in dogs ( 15). Increased levels of angiotensin, a potent vasoconstrictor, could increase resistance to blood flow in the peripapillary choroid. This could critically re- OPTIC NEUROPATHY AND ANEMIA 247 duce prelaminar optic nerve blood flow and result in AlON, even days subsequent to the hemorrhage ( 8). AlON associated with nutritional anemia has seldom been reported. Cowers' reported two young women with optic nerve head swelling, central visual loss, and iron deficiency anemia ( 16). Review of these cases, however, reveals that these patients' hematocrits were greater than 30, and that ocular involvement was bilateral. Similarly, Adams and colleagues described one case of " optic neuritis" associated with a cecocentral scotoma in a series of patients with pernicious anemia ( 17). These cases probably represented incidental optic neuritis secondary to demyelinating disease. Lubeck reported a young woman with iron deficiency anemia, hemorrhagic retinopathy, bilateral optic disc edema, and mildly constricted visual fields ( 18). However, lumbar puncture revealed elevated intracranial pressure. The iron deficiency anemia was treated and the papilledema resolved. Our patient's clinical presentation was AlON. The pathogenesis probably had little to do with decreased perfusion pressure; there was no hypotension documented, or orthostatic symptoms. Foulds hypothesized that a low hematocrit could sufficiently reduce the blood's oxygen carrying capacity, resulting in AlON ( 12). Decreased oxygen delivery to the prelaminar optic nerve due to an extremely low hemoglobin concentration is the most plausible mechanism of pathology in our patient. In summary, AION can be associated with nutritional anemia. Hypoperfusion and endogenous vasoconstrictors may not necessarily be prerequisites. REFERENCES 1. Macan Markar M, Peiris J, De Silva G, et al. Retinopathy in megaloblastic anemias. Trans R Soc Trap Med Hyg 1969; 63: 39S-- 406. 2. Aisen M, Bacon B, Goodman A, et al. Retinal abnormalities associated with anemia. Arch Ophthalmol 1983; 101: 1049- 52. 3. Foster R. Incidence of retinal hemorrhage in severe anemia. TrailS R Soc Trap Med Hyg 1970; 64: 99- 101. 4. Rubinstein R, Yanoff M, Albert D. Thrombocytopenia, anemia, and retinal hemorrhage. Am J Ophthalmol 1968; 65: 435- 9 5. johnson M, Kincaid M, Trobe J. Bilateral retrobulbar optic nerve infarctions after blood loss and hypotension. Ophthalmology 1987; 94: 1577- 84. 6. Chisholm I. Optic neuropathy of recurrent blood loss. Br J OphthalmoI1969; 53: 289- 95. 7. Levatin P. Atrophy of the optic nerve following hemorrhage. Arch OphthalmoI1947; 37: 18- 24. 8. Hayreh 55. Anterior ischemic optic neuropathy. Ophthalmology 1987; 94: 1488- 502. 9. Lockett S. Blindness associated with hemorrhage. Br J Ophtlwlmol 1949; 33: 534- 55. 10. Duke- Elder S. The blood dyscrasias; system of ophthalmology. St. Louis: C. V. Mosby Co., 1967; 10: 373- 407. 11. Hayreh 55. Anterior ischemic optic neuropathy. Br J Ophthai mol 1974; 58: 955- 89. 12. Foulds W. Visual disturbances in systemic disorders; optic neuropathy and systemic disease. TrailS Ophthalmol Soc UK 1969; 89: 125- 46. 13. jaben 5, Glaser J, Daily M. Ischemic optic neuropathy following general surgical procedures. I Clill Neura Ophtlwlmol 1983; 3239- 44. 14. Servilla K, Groggel G. Anterior ischemic optic neuropathy as a complication of hemodialysis. Am J Kidney Dis 1986; 8: 61- 3. 15. Zanchetti A, Stella A, Leonetti G, et al. Control of renin release; a review of experimental evidence and clinical implications. Am I Cardiol 1976; 37: 675- 91. 16. Gowers w. A manual and atlas of medical ophthalmoscopy London: j. 5. A. Churchill, 1882: 203- 4. 17. Adams P, Chalmers T, Foulds W, et al. Megaloblastic anemia and vision. Lallcet 1967; 2: 229- 33. 18 Lubeck Mj. Papilledema caused by iron- deficiency anemia. TrailS Am Acad Ophthalmol Otolaryllgol 1959; 63: 306- 10. I CIIII NCllrlJ-[ J!, I'lh" lm" I, Vol. 10, No. 4, 1990 |
