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Show Journal of CIiIl; CIlI Neuro- ophlluJlmology 11( 4); 268- 272. 1991. © 1991 Raven Press, Ltd., New York Giant Suprasellar Varix: An Unusual Cause of Chiasmal Compression Sylvie Mirabel, M, D., Bertil Lindblom, M. D., Ph. D., Van V. Halbach, M. D., and William F. Hoyt, M. D. A 63- year- old woman developed visual field defects consistent with lateral compression of the optic chiasm. The cause of the compression was found to be a giant venous varix formed by the dilatation of the outflow vein from a dural arteriovenous fistula located in the superior petrosal sinus. After embolization and surgical obliteration of the fistula, the patient's visual function improved markedly. Key Words: Dural arteriovenous fistula- Intracerebral venous varix- Optic chiasm- Superior petrosal sinusVisual fields. From the Neuro- Ophthalmology Unit, Department of Neur~ logical Surgery ( S. M., B. L., W. F. H.) and Department of Radiology ( V. V. H.), School of Medicine, University of California, San Francisco, California, U. S. A. Dr. Lindblom is on leave of absence from the Department of Ophthalmology, University of Goteborg, Sahlgren's HospitaL 5- 41345 Goteborg, Sweden. Address correspondence and reprint requests to Dr. William F. Hoyt at Department of Neurological Surgery, % The Editonal Office, 1360 Ninth Avenue, Suite 210, San Francisco CA g · nn. USA. ' 268 Giant arteriovenous varices ( venous aneurysms) are well- recognized but rare vascular anomalies. A varix is always associated with another type of vascular malformation. For the most common venous aneurysms, those affecting the vein of Galen, the underlying cause is an abnormal arteriovenous communication formed during early embryogenesis ( 1). Less commonly, the underlying cause is a dural arteriovenous fistula ( 2). Very rarely, a giant varix is secondary to a venous angioma, as described most recently by Maiuri et al. ( 3). We report an unusual case in which a giant varix in the suprasellar region compressed the optic chiasm, causing visual field deficits. The underlying cause was a dural arteriovenous fistula located in the superior petrosal sinus. The fistula was successfully treated with endovascular embolization and surgery, and the patient's vision subsequently improved. CASE REPORT A 63- year- old nurse was examined approximately 1 month after she noticed blurred vision in both eyes. Her medical history was remarkable for systemic hypertension and an 8- year history of diabetes mellitus, treated with insulin for the previous 3 years. She had not noticed any cranial bruit. The patient's visual acuity was 20/ 40 in the right eye and 20/ 30 in the left. Her eye examination showed no other abnormal results except for mild lens opacities and minor age- related changes. Perimetry was not performed at this initial examination. During the ensuing 3 months, her visual acuity deteriorated to 20/ 200 in the right eye and 20/ 40 in the left. Evaluation of visual fields at this time showed incongruous left homonymous hemianopia ( Fig. 1)_ Magnetic resonance imaging ( MRI) disclosed a suprasellar vascular anomaly ( Fig. 2). GIANT SUPRASELLAR VARIX FIG. 1. Goldmann visual fields before treatment of the dural fistula. 269 Selective arteriography of the right internal ( Fig. 3) and external ( Fig. 4) carotid arteries revealed a dural arteriovenous fistula in the superior petrosal sinus. The fistula was supplied by the middle meningeal artery and the meningohypophyseal trunk. On either side of the fistula, the superior petrosal sinus was obliterated, and the venous drainage was diverted to an enormously dilated anterior pontomesencephalic vein. The superior segment of this vein compressed and displaced the optic chiasm. Because of progressive deterioration of vision and the very high risk of hemorrhage, the dural fistula was treated with endovascular embolization, and the fistula site was then obliterated sur- FIG. 2. Mid- sagittal n- weighted MR image demonstrates an area of signal void extending superiorly in the suprasellar cistern, displacing and effacing the optic chiasm ( arrows). gically. A postoperative arteriogram confirmed complete obliteration ( Fig. 5). Follow- up examination 3 months after surgery showed that the patient's visual acuity had recovered to 20/ 30 - 2 in both eyes, and her visual fields had improved dramatically. The most noticeable defect at this point was a subtle left hemianopia in her left eye ( Fig. 6). DISCUSSION The underlying cause of the venous varix formation in our patient was a dural arteriovenous fis- " FIG. 3. Right internal carotid angiogram, lateral projection, demonstrates a dural fistula ( straight arrows) supplied by cavernous branches of the internal carotid artery. The venous drainage is to a dilated anterior pontomesencephalic vein ( curved open arrows) and then to mesencephalic veins ( curved solid arrows). JClin Neurcrophlhalmol, Vol. 11, No. 4, 1991 270 S. MIRABEL ET AL. FIG. 4. Arteriogram of the right external carotid artery. anteroposterior projection. demonstrates the same dural fistula site ( straight arrows) draining to a dilated pontomesencephalic vein ( curved open arrows). tula. There are several mechanisms by which dural fistulas can cause visual deterioration. Most often, dural cavernous fistulas ( 2) and other fistulas that communicate directly with the cavernous sinus ( 4) produce visual loss by causing orbital venous hypertension ( 5). The severity of visual loss, as well as that of proptosis, chemosis, and conjunctival injection, correlates not only with the amount of A B FIG. 5. Arteriograms of the right external ( A) and internal ( 8) carotid arteries, lateral nrnjectlon demonstrate complete obliteration of the fistula after endovascular em- - - : I '--::: orv GIANT SUPRASELLAR VARIX --- ru--::::-. ~' I ' T-' I FIG. 6. Goldmann visual fields three months after treatment of the dural fistula. 271 arteriovenous shunting but also with the amount of dilatation of the superior ophthalmic vein and the development of venous thrombosis ( 6). In post- traumatic cavernous sinus fistulas, an arterial steal mechanism in addition to venous hypertension may contribute to orbital ischemia ( 7). However, in patients with low- flow dural fistulas, this steal mechanism seems to be less important ( 5). Another mechanism for visual loss with dural fistulas is chronic atrophic papilledema from occlusion of the superior or lateral dural sinus ( 5). Rarely, the cause of visual loss is compression of an optic nerve ( 8) or the chiasm ( 9) by a dilated cavernous sinus. In our patient's case, however, none of these mechanisms was responsible for the visual loss. Her visual field defects were caused by mechanical compression of the chiasm by the giant suprasellar varix. It is unusual that blurred vision was the only symptom from the venous varix and that the underlying arteriovenous fistula did not cause symptoms. It is also interesting that she heard no bruit: pulsatile tinnitus or bruit is common when a fistula involves a dural venous sinus in the temporal bone. When the dural sinus occludes and the fistula drains through cerebral veins, as in our patient, bruit often disappears ( 5). We are aware of only one previous case in which compression of the visual pathways was ascribed to a varix. Lasjaunias et al. described a 57- year- old woman who had epistaxis, seizures, and visual field loss ( 10). In that case, a dural arteriovenous malformation was located in the cribriform plate, and its venous outflow had caused dilatation of an olfactory vein and the basal vein of Rosenthal. A patient with a giant varix that appeared in a location similar to that in our patient but that did not disturb visual function was described by Martin et al. ( 11). In this patient, the varix compromised the function of the hypothalamus, causing a deficiency of growth hormone. However, her visual fields as assessed by confrontation methods were reported to be normal. Acknowledgment: Financial support for Dr. Lindblom has been provided by Foreningen De Blindas Viinner, Goteborg, The Sweden- America Foundation, Stockholm, Bertil and Carmen Regners Fond, Stockholm, Karin Sandqvists Stiftelse, Stockholm, and WennerGren Center Foundation, Stockholm. REFERENCES 1. Raybaud CA, Strother CM, Hald JK. Aneurysms of the vein of Galen: embryonic considerations and anatomical features relating to the pathogenesis of the malformation. Neuroradiology 1989; 31: 109- 28. 2. Vinuela F, Drake C. Fox AJ. Pelz D. Giant intracranial varices secondary to high- flow arteriovenous fistulae. JNeurosurg 1987; 66: 198-- 203. 3. Maiuri F, Gangemi M, Iaconetta G. Giant intracranial varix associated with venous angioma and intracerebral hemorrhage. Acta Neural 1990; 12: 231~. 4. Barnwell SL, Halbach VV, Dowd CF, Higashida RT, Hieshima GB. Dural arteriovenous fistulas involving the inferior petrosal sinus: angiographic findings in six patients. AJNR 1990; 11: 511~. 5. Lasjaunias P, Chiu M, Brugge KT, Tolia A, Hurth M, Bernstein M. Neurological manifestations of intracranial dural arteriovenous malformations. J Neurasurg 1986; 64: 724- 30. 6. Dowd CF, Halbach VV, Barnwell SL, Higashida RT, Hieshima GB. Occlusion of the anterior superior ophthalmic vein in carotid- cavernous fistulae acutely aggravating visual symptoms. Neuroradialogy 1991; 33: 142- 3. J Clin Neuro- ophthalmol, Vol. 11, No. 4, 1991 272 S. MIRABEL ET AI. 7. Sanders MD, Hoyt WF. Hypoxic ocular sequelae of carotidcavernous sinus fistulae. Br I Ophthnlmol 1969; 53: 82- 97. 8. Hedges TR III, Debrun G, Sokel S. Reversible optic neuropathy due to carotid- cavernous fistula. I Clin Neuro Ophthalmol 1985; 5: 37- 40. 9. Weinstein JM, Rufenacht DA, Partington CR, et al. Delayed visual loss due to trauma of the internal carotid artery. Arch NeuroI1991; 48: 49~ 7. JClin NeuTa-< Jphlhalttwl. Vol. 11 . " , . 10. Lasjaunias P, Halimi P, Lopez- Ibor L, Sichez ] P, Hurth M, de Tribolet N. Traitement endovascuJaire des malformations vasculaires durales ( MVD) pures " spontanees." Revue de 23 cas explores et traites entre mai 1980 et octobre 1983. Neurochirurgie 1983; 30: 207- 23. 11. Martin NA, Macagba- Crain CL, Geffner M, Peacock W. Isolated growth hormone deficiency associated with a giant arteriovenous varix. Neurosurgery 1990; 27: 295- 9. |
