Journal of Neuro-Ophthalmology, December 1991, Volume 11, Issue 4

Amaurosis fugax due to pituitary tumor.

Amaurosis fugax in a younger person in whom premature atherosclerotic disease and cardiac emboli have been eliminated is usually benign. We describe a 25-year-old man with recurrent painless left monocular visual loss lasting from 5 to 45 minutes. Initial physical examination, carotid ultrasound, and electrocardiogram were normal. Goldmann visual field testing demonstrated a small, left paracentral defect. Neuroimaging studies were initially declined for economic reasons, but later a magnetic resonance image disclosed a large pituitary tumor displacing the left optic nerve and chiasm. The tumor was removed via a transphenoidal approach, and the episodic visual symptoms disappeared. We stress that amaurosis fugax in young patients is not necessarily benign. A specific etiology should be diligently sought, particularly when ocular signs are present.

' 0 1991 Raven Press, Ltd., New York Amaurosis Fugax Due to Pituitary Tumor Lucy y, Din, M. D., B. Todd Troost, M. D., Allen D. Elster, M. D., and Andrew J. Fiedler, M. D. Amaurosis fugax in a younger person in whom prema­ture atherosclerotic disease and cardiac emboli have been eliminated is usually benign. We describe a 25­year- old man with recurrent painless left monocular vi­sual loss lasting from 5 to 45 minutes. Initial physical examination, carotid ultrasound, and electrocardiogram were normal. Goldmann visual field testing demon­strated a small, left paracentral defect. Neuroimaging studies were initially declined for economic reasons, but later a magnetic resonance image disclosed a large pitu­itary tumor displacing the left optic nerve and chiasm. The tumor was removed via a transphenoidal approach, and the episodic visual symptoms disappeared. We stress that amaurosis fugax in young patients is not nec­essarily benign. A specific etiology should be diligently sought, particularly when ocular signs are present. From the Department of Neurosciences ( L. Y. D.), University of California, San Diego, San Diego, California; Departments of Neurology, ( B. T. T.), Radiology ( A. D. E). and Internal Medicine ( A.}. F.), Wake Forest Universitv Medical Center, Winston­Salem, North Carolina, U. S. A. ' Address correspondence and reprint requests to Dr. Lucy Y. n, rr .~ t r"' e', 1flm" nt Clf '\ IeunhciL'nces H- 815. UCSD Medical -.' "'", [ lle'~,' CA Q211J3. u. s. A. 254 Amaurosis fugax occurs most commonly in older patients as a result of an embolus from an atherosclerotic carotid artery. Amaurosis fugax oc­curs rarely in young persons, and is often believed to be due to migraine if the episodes are followed by headache ( 1). Atherosclerotic carotid artery dis­ease is unlikely in this age group ( 2). In a previ­ously reported series of young persons with amau­rosis fugax, frequently there was no discernable cause, even after careful evaluation of history and laboratory findings ( 3). Furthermore, follow- up studies have indicated that young persons with amaurosis fugax rarely proceed to stroke, leading investigators to conclude that amaurosis fugax in this age group is benign, implying that an exten­sive evaluation of a young patient is not warranted ( 4). CASE REPORT Between January and May 1989, a 25- year- old man experienced at least 40 episodes of sudden, left- sided, painless, monocular visual loss lasting 5- 45 minutes. Vision in the left eye diminished to light perception, described as " looking through a Kleenex" during these periods, lasting an average of 20 minutes with rapid return to normal. Physical activity or position did not precipitate the occur­rences. On rare occasions the episodes were fol­lowed by a mild generalized headache. Initial ex­amination elsewhere in May of 1989 was normal except for 20/ 25 vision in the right eye believed to be due to old amblyopia. The left eye vision was 20/ 15. No afferent pupillary defect was noted. Laboratory evaluations, including carotid Doppler ultrasound, electrocardiogram, serum chemistries ( SMAC), antinuclear antibodies ( ANA), and sedi­mentation rate, were normal. Goldmann visual fields, in May of 1989 demonstrated a small left paracentral defect not approaching vertical me­ridian ( Fig. 1A). The patient declined imaging studies for economic reasons. Because some epi- AMAUROSIS FUGAX DUE TO PITUlTARY TUMOR 255 A L. EFT IEYE RIIGHT EYE B LEFT EYE RIGHT EYE FIG. 1. A: Goldmann Visual Fields, May 1989. Left eye: left paracentral defect not approaching vertical meridian. Visual acuity 20/ 15 O. S. Right eye: possible increased blind spot, but decreased fixation due to old amblyopia. Visual acuity 20/ 25 0.0. B: Automated Humphrey's Perimeter, July 1989. Left eye: Superior temporal defect aligned along vertical meridian. Defect extends inferiorly in both temporal and nasal quadrants Visual acuity 20/ 40 as., 20/ 25 0.0. sodes were followed by mild generalized head­ache, the tentative diagnosis of retinal migraine was made. The patient presented to a second institution one month later, in June, 1989. Visual acuity was 20/ 25 in the right eye and 20/ 40 in the left eye. Color vision was markedly decreased in the left eye. Fundus examination revealed mild pallor of the optic disc on the left. Visual field testing was normal to visual confrontation. The patient was reevaluated in July 1989 at the Wake Forest University Medical Center and found to have visual acuity 20/ 25 right eye, 20/ 40 left eye, subtle left optic atrophy, markedly decreased color vision in the left eye, and a left inferior nasal field defect. Automated Humphrey's perimetry demon­strated a left superior temporal defect aligned along the vertical meridian extending inferiorly in both temporal and nasal quadrants ( Fig. 1B). The patient was examined during an episode of visual I Clin Neuro- ophthalmol, Vol. 11. No. 4. 1991 256 L. Y. OIRR ET AL. A FJG. 3. A: S.:: gintl.~ /,- weigITMd .' vfR ill ..: lye \ TR = 0110, r~ = 20) demonstrates a large inhomogenously enhancing tumor ( arrow) involving the sella. B: Coronal image shows contact of the mass with the left side of the chiasm ( arrow). C and 0: Coronal STIR images of the orbit ( TI = 180, TR = 1,200. TE = 30) demonstrating high signal in the left optic nerve ( arrow). The symmetric high signal in the medial and inferior recti is a normal finding caused by susceptibility changes in the magnetic field be­tween sinus and orbit. loss. He described the sudden onset of loss of vi­sion in the left eye with vision declining from nor­mal to reduced acuity over a period of 5 seconds. When examined, the patient had generalized re­duction in visual function, to hand movements in all quadrants, a central acuity of 20/ 400, and a left afferent pupillary defect. Fundoscopic examina­tion showed no change in the retinal vessels. Vi­sion remained reduced for 30 minutes and then returned gradually to normal at the end of 45 min­utes. No pain was associated with the episode. . · · ,. coin\:, " · ., s performed on I Clln N"" rlHlphthalmo/' Vol. 11, ", 0 of. 0 a high- field ( 1.5 T) system before and after the in­travenous administration of gadopentetate dimeglumine ( Gd- DTPA, 0.1 mmollkg). Routine T1 == weighted coronal and sagittal images were obtained as well as a short T1 inversion recovery sequence ( STIR) to suppress orbital fat and high­light abnormalities of the optic nerves. A large tu­mor mass involving the pituitary was identified with inhomogeneous enhancement on postcon­trast images ( Fig. 2A and B). The carotid arteries were displaced by the tumor but were definitely patent and not encased by tumor; the optic chiasm AMAUROSIS FUGAX DUE TO PITUITARY TUMOR FIG. 3. A low- power photomicrograph of the pituitary tumor demonstrates sheets of uniform benign cells separated by thin strands of connective tissue consistent with a benign adenoma. The tumor was negative for HGH, prolactin, and ACTH with immu­nocytochemical stains. ( Hematoxylin and eosin; original magnification = x 120) 257 was uplifted by the tumor. Abnormal high signal was noted in the left optic nerve on the STIR se­quence ( Fig. 2C and D). This appearance, typically seen with optic neuritis, has never been reported in cases of neuropathy secondary to compression by a mass. Two- vessel cerebral arteriogram revealed bilat­eral lateral displacement of the cavernous portion of the carotid with slight uplifting of the Al seg­ment of the anterior cerebral artery on the right side. Following transphenoidal removal of a pituitary tumor, the patient's visual acuity improved to 20/ 20 and he had no further episodes of amaurosis fugax. The visual field defect in the left eye im­proved, leaving a residual small inferior nasal de­pression which has persisted during a follow- up period of over I year. Pathologic examination of the tumor demon­strated sheets of uniform benign cells separated by thin strands of connective tissue consistent with a benign pituitary adenoma. The tumor was nega­tive for HGH, prolactin, and ACTH with immuno­cytochemical stains ( Fig. 3). DISCUSSION Monocular fleeting loss of vision, lasting sec­onds to minutes, is most often caused by retinal microembolization ( 5). Other cited etiologies in­clude papilledema, drusen, hypotension, arteritis, migraine, anemia, polycythemia ( 6), and antiphos­pholipid antibodies ( 7). We have now documented another, albeit unusual, nonbenign cause: pitu­itary tumor. The exact mechanism in our case remains enig­matic. Possible factors include direct compression of the optic nerve and its blood supply. Of note is the fact that the left optic nerve anterior to the region of compression shows abnormal signal on the STIR image ( Fig. 28). This suggests that the entire nerve was functionally compromised de­spite relatively good visual acuity. The nerve is likely, therefore, to be susceptible to minor vascu­lar, metabolic, and mechanical perturbations. Fur­thermore, the occurrence of intermittent neuro­logic deficits with central nervous system tumors is well documented. Another possible mechanism is intermittent compression of the left cavernous ca­rotid artery by the tumor. The carotid arteries were displaced by the tumor, but were definitely patent and not encased by tumor. Progressive decrease in visual acuity, reduction of color vision, abnormal visual fields, and optic disc pallor, however subtle, must be aggressively evaluated. It is clear that early diagnosis is impor­tant, and we urge the physician to consider more diligent evaluation of the young person with J Clin Neuro- ophthalmol, Vol. 11. No. 4, 1991 258 L. Y. DIRR ET AL. amaurosis fugax when the cause is not readily ap­parent. Acknowledgment: Special thanks to V. R. Challa, M. D. of the Department of Neuropathology, Bowman Gray School of Medicine, for his help in preparing pho­tomicrographs of the pituitary tumor. REFERENCES 1. Tomsak RL, Jergens PB. Benign recurrent transient monoc­ular blindness: a possible variant of acephalgic migraine. Headache 1987; 27: 66-- 9. 2. Eadie MJ, Sutherland JM, Tyrer JH. Recurrent monocular blindness of uncertain cause. Lallcet 1968; 1: 319- 21. 3. Poole CjM, Russell RWR, Harrison R. Amaurosis fugax un­der the age of 40 years. J Neurol Neurosurg Psychiatry 1987; 50: 81- 4. 4. Tippin J, Corbett jJ, Kerber RE, Schroeder E, Thompson HS. Amaurosis fugax and ocular infarction in adolescents and young adults. 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