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Show Journal of Clillical Neunrophthalmology 9( 4): 273- 276. 1989. Pseudodrusen of the Optic Disc Papilledema Simulating Buried Drusen of the Optic Nerve Head John E. Carter, M. D., Michael D. Merren, M. D., and Barry M. Byrne © 1989 Raven Press, Ltd., New York The distinction between true papilledema and pseudopapilledema rests on characteristics of the optic disc when examined ophthalmoscopically. Buried disc drusen frequently simulate papilledema and often result in misdirected diagnostic maneuvers in search of a cause for presumed intracranial hypertension. When an elevated optic disc exhibits an irregular, " lumpy, bumpy" border, a diagnosis of buried drusen of the optic nerve is usually made. We report a case with papilledema secondary to increased intracranial pressure in which the margins of the swollen optic disc presented this lumpy, bumpy border characteristic of buried drusen. The lumpy character of the disc border disappeared with resolution of the papilledema, and ultrasonography demonstrated the absence of any buried drusen. Other characteristics of papilledema, including extension of the disc swelling into the peripapillary nerve fiber layer, telangiectasia of the superficial vessels of the optic disc, and obscuration of the retinal vessels as they crossed the margins of the optic disc, provided strong evidence of true papilledema and remain the most reliable findings allowing a distinction between true papilledema and pseudopapilledema. Key Words: Papilledema- Drusen- Optic nerve. From the Departments of Neurology ( J. E. C., M. D. M.) and Ophthalmology ( J. E. C., B. M. B.), University of Texas Health Science Center, San Antonio, Texas. Address correspondence and reprint requests to Dr. John E. Carter, Department of Neurology, University of Texas Health Science Center, San Antonio, TX 78284, U. S. A. 273 Anomalous elevation of the optic disc may bear a striking similarity to true papilledema and " is a major cause of unnecessary alarm and misdirected diagnostic procedures" ( 1). Conversely, chronic papilledema has been noted to produce visible intrapapillary refractile bodies of the optic discs ( 25), which have occasionally been noted in other conditions as well ( 5- 10). When there are no visible drusen at the surface of the optic nerve head, buried drusen are diagnosed when the border of the elevated optic disc assumes an irregular, " lumpy, bumpy" appearance. We report a case with papilledema secondary to increased intracranial pressure in which one optic disc exhibited mild papilledema while the other demonstrated features of papilledema but an appearance of the disc margin that was thought to be diagnostic of buried drusen. The lumpy character of the disc border disappeared with resolution of the papilledema, and ultrasonography demonstrated the absence of any buried drusen. CASE REPORT A 35- year- old woman initially noted a vague distortion of vision in a diagonal strip across the vision of her right eye. This resolved after a few days, but was replaced by recurrent episodes of dimming of the vision of the right eye. These could be precipitated by bending over. When she first awoke in the morning, the vision in her right eye was black for a few seconds and then faded in. She was also experiencing headache in the right frontal and eyebrow region. The results of her neurological examination were entirely normal except for some mild hypotonia on the right side and abnormal optic discs ( Fig. 1a and b). The right optic disc 274 f. E. CARTER ET AL. FIG. 1. ( a) Right optic disc at the time of the initial evaluation. Note lumpy, bumpy border to the disc, especially temporally. Note also signs of true disc swelling, extension of the swelling into the peripapillary nerve fiber layer, obscuration of the retinal vessels as they cross the margins of the optic disc, and telangiectasia of the small disc vessels. ( b) Left optic disc at the time of the initial evaluation. Note mild papilledema. This resolved and the disc appeared normal following posterior fossa decompression. ( c and d) Right optic disc 3 months after posterior fossa decompression showing resolution of the optic disc swelling with no indication of buried or superficial drusen. had a " lumpy, bumpy" outline strongly indicative of optic nerve drusen, but there was also swelling present in the peripapillary nerve fiber layer with obscuration of the retinal vessels as they crossed the optic disc onto the retina and mild telangiectasia of the superficial vessels of the optic disc. There was no indication of drusen on the left side, which did exhibit mild but definite papilledema. The results of a computed tomographic examination with and without contrast were normal except for minimal effacement of the right lateral recess of the fourth ventricle. The lateral and third and fourth ventricles were not dilated. Magnetic resonance imaging ( MRI) ( Fig. 2) demonstrated a process dif~ I Clin Neuro- ophthalmol, Vol. 9, No. 3, 1989 fusely enlarging the right cerebellar hemisphere and involving primarily the cerebellar cortex, impinging on the cerebellar white matter. A gyriform pattern was seen that corresponded to the enlarged but preserved folia of the cerebellar cortex. Exploration and decompression of the posterior fossa were achieved by amputation of the lateral one- third of the right cerebellum. Pathologic study of the involved cerebellar cortex confirmed the diagnosis of dysplastic gangliocytoma of the cerebellum ( Lhermitte- Duclos disease). Following surgery, the patient made an uneventful recovery. No residual neurological deficits were present except for continued mild hypo- PSEUDODRUSEN OF THE OPTIC DISC 275 FIG. 2. Magnetic resonance image of the posterior fossa showing abnormal signal intensity of the right cerebellum. The abnormality has a gyriform appearance characteristic of the pathologic picture of dysplastic gangliocytoma of the cerebellum, which the lesion proved to be at surgery. Reproduced with permission from Carter et aI., J Neurosurg 1988; 00. tonia on the right side and no neurological symptoms have occurred during a 6- month follow- up. The papilledema underwent gradual resolution ( Fig. Ic and d). As the disc edema in the right eye resolved, the optic disc became clearly visible and the irregular border of the swollen disc resolved into an entirely normal optic nerve with no evidence of visible or buried drusen. An echographic study ( Fig. 3) confirmed the absence of any drusen bodies in the optic nerve. DISCUSSION The subject of this report presented with vague, lateralized headache and visual symptoms attnbutable to papilledema, but also seen in conditions with full optic discs including optic disc druse~ and optic disc dysplasias ( 1). The most dra. mahcally elevated optic disc showed a markedly megular border that strongly suggested the presence of buried drusen. There were even one or two very small, bright refractile areas in the superficial disc substance. Despite this irregular border, there was blurring of the peripapillary nerve fiber layer, obscuration of the retinal vessels as they crossed the disc margins, and telangiectasia of. sever~ l superficial disc vessels, enabling a firm diagnOSis of papilledema in this eye, which was confirmed by the FIG. 3. Orbital echography of the right eye 3 months after posterior fossa decompression. Vertical axial scan at normal amplification ( a) and horizontal axial scan at low amplification ( b) indicate that the optic nerve is still slightly elevated by echography. However, the high reflectance pattern characteristic of buried drusen of the optic nerve is not present. mild papilledema with no signs of drusen in the fellow eye. The lumpy appearance of the optic disc was so dramatic, however, that the diagnosis was presumed to be true papilledema superimposed on buried disc drusen. A diagnosis of buried drusen might have delayed the diagnosis of intracranial hypertension secondary to a cerebellar mass lesion, especially if MRI had not been available to demonstrate the striking abnormality in the patient's cerebellum. Chronic papilledema is well known to produce visible intra papillary refractile bodies in the superfi- FIG. 4. Ultrasound B- mode scan echogram in a patient with drusen of the optic nerve head for comparison with the patient presented here. With low amplification the surface of the optic nerve head exhibits a high reflectance abnormality representing drusen. J Clin Neuro- ophthalmol. Vol. 9. No. 4, 1989 276 J. E. CARTER ET AL. cial nerve fiber layer that have been reported to result in the misdiagnosis of optic disc drusen and delay the diagnosis of intracranial hypertension ( 11). These small refractile bodies are now widely recognized as a consequence of chronic disc swelling ( 4,5,7,8,10,11) and should not be mistaken for drusen of the optic nerve head. However, no case has been reported in which buried drusen of the optic nerve have been mimicked in the fashion demonstrated in this patient. In their textbooks, both Glaser ( 1) and Miller ( 4) enumerate criteria for distinguishing pseudopapilledema from true papilledema. While a lumpy, bumpy border to the optic disc is very suggestive of optic disc drusen, specific characteristics of the optic disc swelling, induding edema of the peripapillary nerve fiber layer, telangiectasia of the superficial vessels of the optic nerve head, and obscuration of the retinal vessels as they cross the optic disc, should be used to distinguish true papilledema from pseudopapilledema. I Clin Neuro- ophthalmol, Vol. 9, No. 3, 1989 REFERENCES 1. Glaser JS. Neuro- ophthalmology. Hagerstown, MD: Harper and Row, 1978: 76. 2. Walsh FB, Hoyt WF. Clinical neuro- ophthalmology, 3rd ed. Baltimore: Williams and Wilkins, 1969: 582. 3. Spencer WH. Drusen of the optic disc and aberrant axoplasmic transport. Ophthalmology 1978; 85: 21- 38. 4. Miller NR. Walsh and Hoyt's clinical neuro- ophthalmology; vol!. 4th ed. Baltimore: Williams and Wilkins, 1982: 365. 5. Iso OM. Pathology and pathogenesis of drusen of the optic nervehead. Ophthalmology 1981; 88: 1066- 79. 6. Spencer WH, in Discussion, Iso OM. Pathology and pathogenesis of drusen of the optic nervehead. Ophthalmology 1981; 88: 1079-- 80. 7. Lorentzen SE. Drusen of the optic disk: a clinical and genetic study. Acta Ophthalmol 1966; 90( suppl):~ 175. 8. Apple DJ, Rabb MF. Clinicopathologic correlations of ocular disease. 2nd ed. St Louis: CV Mosby, 1978: 425. 9. Schlezinger WS, Waldman J, Alpers BJ. Drusen of the optic nerve simulating cerebral tumor. Arch Ophthalmol 1944; 31: 509- 16. 10. Sibony PA, Kennerdell JS, Slamovits IL, Lessell S, Krauss HR. Intrapapillary refractile bodies in optic nerve sheath meningioma. Arch OphthalmoI1985; 103: 383- 5. 11. Okun E. Chronic papilledema simulating hyaline bodies of the optic disc. Am JOphthalmol 1962; 53: 922- 7. |
