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Show I 19Hh Raven Press, New York A Case of Convergence Evoked Eyelid Nystagmus R. S. Howard, M.B., M.R.C.P. The clinical ,md radil)ll)gical features of a piltient with convergence e\'oked, upward bt',lting eyelid nystagmus, which occurrt'd independently of ocular upbeating !l\'stagmus, are presented. The eyelid nystagmus resulted fwm il large angiomatous lesion distorting the blol)d supply to the pontomesencephalic and pontomedullarv junctions. From The National Hospital for Nervous Diseasl's, Queen Square, London, U.K. Address correspondence and reprint requests to Dr. R. S. Howard, Department of Neurology, 51. Thomas' Hospital, London 5EI 7EH, U.K. /69 Vertical nystagmus often is accompanied by synchronous movements of the eyelids, which have similar periodicity. Spontaneous "lid nystagmus" is reported as an isolated finding accompanying ocular nystagmus and other neurological abnormalities. Localisation of the responsible lesions has demonstrated widespread disease processes involving the cerebellum and brainstem. A case of convergence evoked eyelid nystagmus, which occurred with intermittent phases of upbeat, is reported. Neurological examination, angiography, and computed tomography (eT) scanning demonstrated an extensive angioma involving the pontomesencephalic and pontomedullary junctions. CASE REPORT A previously healthy 18-year-old woman suddenly developed painless diplopia in all directions of gaze, which resolved after 1 week. Two months later, the diplopia recurred. There was no headache, vertigo, tinnitus, or pain on ocular movement. On examination, it was noted that the occiput was tilted and the nasum turned to the left shoulder. Visual acuity, colour vision, fields, pupillary reactions, and fundi were normal. In the primary position, there was a skew deviation of the right eye upward and outward. There was a partial right sixth nerve palsy with bilateral gaze paretic horizontal nystagmus more marked to the right than to the left. There was an intermittent bilateral primary position upbeat nystagmus, and both binocular convergence and monocular accommodation on a near target provoked marked eyelid nystagmus with a fast phase in the upward direction and a slow phase downwards. Smooth pursuit movements were markedly hypometric in both horizontal and vertical planes. 170 R. S. HOWARD Saccadic velocities were slow, but there was no internUdl." H ophthalmopll.'gia. The slow phase velocity of optokinetic nystagmus was markedly hypometric in till' horizontal plane, with a directional preponderance to the right. OptokInetiC nystagmus in thl.' vertical plane was relatively normal with a directional prepondl.'rance upwards. On the right sidt" therl.' was diminished corneal sensation, lower motor neurone facial weakness, and a mild sensorineural deafness. The lower cranial nerves were intact. There was a mild increase in tone of the left leg with minimal pyramidal weakness, and the tendon reflexes in the limbs were brisker on the left than on the right with an equivocal left-sided plantar response. There were no sensory or cerebellar signs, and general examination was unremarkable; no cranial bruit was audible. Caloric tests showed a directional preponderance to the right and an absence of fixation suppression. Responses to steps in rotational velOCity (400 /s) showed a directional preponderance to the left. Routine haematology and biochemistry, visual evoked responses, and electroencephalogram were normal, but somatosensory evoked potentials showed cortical responses to left arm stimulation, suggestive of a lesion between the brainstem and right somatosensory cortex. Brainstem auditory evoked potentials were deranged in a manner compatible with an asymmetrical upper brainstem lesion, worse on the right. Audiological investigations showed impaired speech perception in the right ear, with absent stapedial reflexes on the right and only ipsilaterally evoked retlexes on the left. High resolution CT scanning (Fig. 1) showed an extensive enhancing lesion in the right side of the pons with mass effect compressing the fourth ventricle. There were noted also several denselv enhancing areas thought to be large vessels. The appearance of the right pontine mass lesion was suggestive of an angioma extending to the right of the midline, lying in the region of the pons and upper medulla. Angiography (Fig. 2) showed that the angioma was supplied predominantly by the hypertrophied right superior cerebellar and pontine arteries. DISCUSSION Phasic, rhythmical jerking of the upper eyelids, evoked by convergence, was described first by Pick in 1916 (1) in a patient with pseudobulbar and cerebellar signs. The rostrally beating and gaze evoked nystagmus, also present in this patient, were considered to be independent phenomena. FIG. 1. High resolution CT scanning shows an extensive enhancing lesion in the right side of the pons with mass effect compressing the fourth ventricle. Its appearance suggests an angioma extending to the right of the midline in the region of the pons and upper medulla. Also noted are several densely enhancing areas thought to be large vessels. Subsequentl~', Sanders et al. (2) distinguished three varieties of e~'eIid nystagmus, viz., normal synchronous movements of the lids and eyes during evoked or spontaneous nystagmus, convergence evoked lid n~'stagmus in the absence of ocular nystagmus, as described by Pick, and a synchronous jerking of the lids occurring with certain lateral gaze evoked nystagmus (3). In the previousl~' reported cases of convergence evoked lid nystagmus without ocular nystagmus, the intracranial damage vvas too extensive to provide localisation. Pick's original patient (1) had a progressive neurological disorder, the patient reported by Sanders et al. (2) had a sarcoma originating in the cerebellar vermis, and one patient described by Safron et al. (-l) had a tumour of the anterior vermis extending into the mesencephalon. Salisachs and Lapresle (5) described a case of convergence evoked eyelid nystagmus associated with the Miller Fisher syndrome, and Daroif et al. (6) anecdotally reported a pathological study in which they found a large area of demyelination in the rostral medulla, which extended laterally across the medial lemniscus from the upper border of the inferior olive to the ventral limits of the medial longitudinal fasciculus. Rostral (up)-beat and caudal (down)-beat nystagmus share the characteristics that they are fre- CONVERGENCE EVOKED EYELID NYSTAGMUS 171 FIG. 2. Angiography shows that the angioma was supplied predominantly by the hypertrophied right superior cerebellar and pontine arteries. quently enhanced and occasionally suppressed by vergence, and some have a slow phase velocity which is modulated by tilt of the head with respect to gravity. The localising value of downbeat nystagmus is SOO/C in favour of cerebellar disease, whereas the majority of reported cases of upbeat nystagmus have been associated with lesions of the tegmentum at the pontomedullary and pontomesencephalic borders (7). The clinical significance of the case presented here is that the localisation of the lesion responsible may correspond to the area of the pons and the medulla identified by Fisher et a!. (7) as associated with upbeat nystagmus. However, the angiomatous lesion was large and the blood supply to the pontomedullary and pontomesencephalic junction was distorted considerably. Therefore, precise anatomical localisation of the lesion causing dissociation of the lid and ocular nystagmus was not possible. Acknowledgments: I would like to thank Dr. R. R,1SS Russell and Mr. M. D. Sanders for their permission 10 publish details of this patient, and Dr. M. Gresty for his help in the preparation of this paper. I also would like to thank Miss V. Spencer for her secretarial assistance. REFERENCES 1. Pick A. Kleine Beitrage zur Neurologie des Auges: Uber den Nystagmus der Bulbi begleitende gleichartige Be\\'egungen des obern Augenlides. (Nystagmus des Oberlides). Arch AII-;l'Ilhick 1916;80:36-40. 2. Sanders MD, Hoyt WF, Daroff RB. Lid nystagmus evoked by lateral convergence: an ocular electromyographic stud~" I Nt'lirol Nfllrt1;'lIrs p;.ydliatn/ 1968;31:368-71. 3. Daroff RB, Hoyt WF, Sanders MD, Nelson LR. Gaze evoked eyelid and ocular nystagmus inhibited by the near reflex. Unusual phenomena in a lateral medullan' syndrome. I Nelln,1 Nellr";'lIrs P;'llchiatnl 1908;31:362-7. 4. Safran A, Bt'rnl'V J. S<lfr<ln E. Convergence evoked ewlid nystagmus. Am I 0l'htllllill/l,1 1982;93:48-51 5. Salisachs P. Lapresle J. Upper lid jerks in the Fisher Svndrome. ElIr Nellr,,1 1977;15:237-40. 6. Daroff RB, Twost BT, Dell'Osso LF. Nvstagmus and reI< lted ocular oscillations. In: Duane TO, ed. Clillical0l'hthalmoI< 1SI/. 1'01. 2. Nt'w York: Harper and Row, 1976, chapter /1:14-15. 7. Fislll'r A, Crl'sty M, Ch.lmbers D. Rudge P. Primary posilinn upbealin!, nyst,l!,mus. flmill 1983;106:949-64. I CliJl N"lIro-ol'ltthafJl)(l/. Vol. 6. No.3, 1986 |
