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Show Journal of Neuro- Ophthalmology 16( 1): 41- 43, 1996. > 1996 Lippincott- Raven Publishers, Philadelphia Superior Oblique Myokymia Associated with a Dural Arteriovenous Fistula Todd C. Geis, M. D., Nancy J. Newman, M. D., and Robert C. Dawson, M. D. Abstract: Superior oblique myokymia ( SOM) is an uncommon ocular motility disorder characterized by intermittent uni-ocular vertical or torsional oscillations with periodic remissions and exacerbations. Although generally idiopathic in origin, isolated case reports have documented its association with intracranial pathology. We present a case of superior oblique myokymia associated with a dural arteriovenous fistula. Key Words: Superior oblique myokymia- Dural fistula- Tinnitus- Arteriovenous fistula. Manuscript received May 23, 1995. From the Departments of Ophthalmology ( T. C. G., N. J. N.), Neurology ( N. J. N.), Neurosurgery ( N. J. N.), and Radiology ( R. C. D.), Emory University School of Medicine, Atlanta, Georgia, U. S. A. Address correspondence and reprint requests to Dr. Nancy J. Newman, Neuro- Ophthalmology Unit, The Emory Eye Center, 1327 Clifton Road, N. E., Atlanta, GA 30322, U. S. A. Superior oblique myokymia ( SOM) is an uncommon ocular motility disorder characterized by episodic, uniocular vertical or torsional oscillations ( 1). While most case series emphasize the benign nature of SOM, there have been reports of its association with intracranial pathology ( 2- 5). We present a case of superior oblique myokymia associated with a dural arteriovenous fistula. CASE REPORT An otherwise healthy 40- year- old woman was referred with a 3- month history of episodic binocular vertical diplopia when reading. The diplopia was appearing sooner into her reading periods, such that she was only able to read 15 pages before stopping. Visual acuity, visual fields, pupillary responses, slit lamp, and ophthalmoscopic examinations were normal. Ocular motility was full. She was ortho-phoric in all fields of gaze. When looking down and to the right, there were intorsional oscillations of the left eye, best appreciated at the slit lamp. Myokymia of the left superior oblique was diagnosed. Magnetic resonance imaging ( MRI) of the brain with gadolinium was normal. Treatment with car-bamazepine was unsuccessful at alleviating her symptoms and was discontinued by the patient. She did not wish to try propranolol and declined surgical intervention. She continued to have increasing difficulty with reading. Eighteen months later, the patient complained of pulsatile tinnitus in the left ear for the previous 9 months, and an arteriogram was performed. Arteriovenous communication between branches of the left middle meningeal and occipital arteries and the sigmoid sinus was revealed ( Fig. 1). The communication was embolized by placing plati- 41 42 T. C. GEIS ET AL. num microcoils in the sigmoid sinus and by supra-selective Ivalon particle injection into feeder branches of the left occipital artery ( Fig. 2). Following embolization, the tinnitus completely resolved and the ocular symptoms improved. Follow- up examination revealed decreased frequency of adventitious torsional ocular movements, and no worsening was reported over the subsequent 1 Vi years. DISCUSSION Presenting with stereotypical signs and symptoms, SOM rarely is challenging diagnostically. Patients usually complain of vertical or torsional diplopia and/ or oscillopsia. Uniocular oscillations can often be induced by moving the affected eye into the field of action of its superior oblique muscle. Treatment is often more difficult. Rosenberg and Glaser ( 6), in a 1983 review of 11 cases, characterized the relapsing and remitting course of SOM, as well as the failure of carbamazepine in providing long- term control. A more recent review ( 7) supports these observations and recommends that superior oblique tenectomy with inferior oblique myectomy be considered for intolerable symptomatology. Both reports stress the lack of development of associated neurologic disease during long- term follow- up. Isolated case reports, however, have docu- FIG. 1. Left external carotid arteriogram, lateral projection, reveals multiple fistulous connections between occipital ( small arrows) and middle meningeal ( arrowheads) arteries and sigmoid sinus ( open arrow). Note sinus is occluded at its proximal end ( curved arrow). FIG. 2. Postembolization left external carotid arteriogram, lateral projection. Multiple platinum wire coils ( arrows) pack the sigmoid sinus and occlude the fis-tulae. mented SOM in association with posterior fossa tumors ( 2- 4) and with adrenoleukodystrophy ( 5). One patient had an astrocytoma of the cerebellar vermis with midbrain tectal compression and obstructive hydrocephalus ( 2). Another report describes a pilocytic astrocytoma expanding within the fourth ventricle, with tectal compression ( 3). In another case, SOM occurred after removal of a cerebellar tumor ( 4). We present a case of SOM in a patient found to have a dural A- V fistula. Although symptoms improved following embolization, they were not completely ablated, and the causative role of the fistula remains speculative. Furthermore, our patient's improvement postoperatively may merely reflect the natural course of this relapsing and remitting disorder. The association of two relatively rare conditions in a healthy young adult, however, is noteworthy. In the patient with SOM who complains of other symptoms suggesting a vascular process, such as pulsatile tinnitus, further diagnostic workup is required. Acknowledgments: Supported in part by Research to Prevent Blindness, Inc., New York, New York, and by P30 EY06360 ( A NIH Departmental Core Grant) Be-thesda, Maryland. REFERENCES 1. Hoyt WF, Keane JR. Superior oblique myokymia. Report and discussion on five cases of benign intermittent uniocular microtremor. Arch Ophthalmol 1970; 84: 461- 7. 2. Morrow MJ, Sharpe JA, Ranalli PJ. Superior oblique myo- / Neuro- Ophthalmol, Vol. 16, No. 1, 1996 SUPERIOR OBLIQUE MYOKYMIA AND DURAL FISTULA 43 kymia associated with a posterior fossa tumor: oculo-graphic correlation with an idiopathic case. Neurology 1990; 40: 367- 70. 3. Dehaene I, Casselman J. Left superior oblique myokymia and right superior oblique paralysis due to a posterior fossa tumor. Neuro- ophthalmology 1993; 13: 13- 6. 4. Inagaki M, Suzuki T, Nakano N, Sekimoto S, Ishikawa H. A case of superior oblique myokymia caused by cerebellar tumor [ in Japanese]. Folia Ophthalmol Jpn 1983; 34: 59- 62. 5. Neetens A, Martin JJ. Superior oblique myokymia in a case of adrenoleukodystrophy and in a case of lead intoxication. Neuro- ophthalmology 1983; 3: 103- 7. 6. Rosenberg ML, Glaser JS. Superior oblique myokymia. Ann Neurol 1983; 13: 667- 9. 7. Brazis PW, Miller NR, Henderer JD, Lee AG. The natural history and results of treatment of superior oblique myokymia. Arch Ophthalmol 1994; 112: 1063- 7. / Neuro- Ophthalmol, Vol. 16, No. 1, 1996 |
