| Description |
This patient was seen at the Yale Eye Center at the age of 37. She had a long history of multiple sclerosis. At age 22, she had an acute attack of optic neuritis in the left eye which recovered fully within three weeks. Some months later she had a recurrent episode in the same eye, which also recovered fully. At age 26, her third attack of MS, was more severe with acute numbness of the left side of the body from the waist down and involving the leg. On exertion and when exposed to heat the left leg became weak and she had difficulty walking. (positive Uhthoff's sign). On this occasion however her signs and symptoms did not remit and over the next few years her deficits gradually progressed until by 1989 she was wheelchair bound. In that year, she was admitted to the Mass General Hospital for evaluation and was found to be very depressed, owing to having to leave her job as a proof reader because of disturbing oscillopsia and blurring of vision. Neuro-ophthalmological examination: Visual acuity (VA): 20/200 OU Reads J2 OD, J4 OS. She was unable to insert her contact lenses owing to marked ataxia of the upper extremities and impaired dexterous movements of the hands. Ocular motility: •Paresis of adduction of the right eye on gaze left •Abducting nystagmus of the left eye on gaze left •Paresis of adduction of the left eye on gaze right •Abducting nystagmus of the right eye on gaze right •Normal convergence •Full vertical gaze •Pendular horizontal oscillations •Intermittent primary position upbeat nystagmus Spinal tap: Eight years and 15 years after the onset of progressive relapsing MS, the cerebrospinal fluid showed an elevation of the protein (60-75mg/dl), an increase in the number of white blood cells (11-15), and elevated IgG with positive oligoclonal bands. Brain MRI: The brain MRI, with T1 and T2 weighted images in the axial and sagittal view showed considerable periventricular bright signals in the T2 WI scans involving the frontal and occipital lobes. The bright signals were greatest in the occipital lobe. A small punctate hyperintense signal was present in the white matter in the posterior limb of the internal capsule on the left side. Several other small punctate hyperintense signals were present in the centrum semiovale bilaterally. Electronystagmogram: 1.Spontaneous and gaze nystagmus - Irregular horizontal eye movement with eyes open and eyes closed. On right lateral gaze with eyes open nystagmus present in the right eye, fast phase to the right. 2.Optokinetic nystagmus (OKN) - Horizontal OKN was attempted with a sinusoidal full field strimulus. No nystagmus was provoked. Down beating OKN provoked with an up moving stimulus. No upbeating nystagmus provoked with down moving stimulus. Impression: Left internuclear ophthalmoplegia (INO) and saccadic breakdown of visual-vestibular interaction consistent with a cerebellar or brainstem lesion because of rotation induced nystagmus and absent optokinetic nystagmus. Oscillopsia, an illusion of movement of the visual world, was the major visual disability in this patient. She was seen in the Low Vision Aid Clinic to see if optical devices could stabilize the retinal image. a) High plus lenses combined with a high minus contact lens (Rushton and Cox, 1987, JNNP Vol 50, 411-415) b)Base out prisms to induce convergence with minus lenses to correct accommodation (as used in congenital nystagmus by (Dickenson Physiological Optics 1986). Prism therapy failed to stabilize her vision. Drug therapy with three different medications, baclofen, meclazine and cogentin was also unsuccessful and because conservative measures failed she was referred for consideration of Botulinum toxin therapy. Botulinium Toxin In 1991 the use of botulinum toxin (botox) to suppress involuntary eye movements had not been well studied. Halgerson reported getting beneficial effects in some patients with nystagmus using intraorbital injections into the eye muscles. At that time no large medical studies were available. The patient was, however, anxious to be treated in an effort to improve her vision to watch TV and, after being fully informed of all the risks and possible complications, she agreed to a trial of botox. The procedure plan was to obtain pre-injection video tapes of her eye movements and then inject botox into the extraocular muscles of the right eye under EMG control. Since her oscillopsia was due to acquired pendular horizontal oscillations, the goal was to dampen and hopefully stop the oscillations by injecting botox into the lateral and medical recti of the right eye. The risk of injecting botox only into these two muscles was the possibility that it would cause diplopia, and that diplopia might be more problematic to her than oscillopsia. The procedure went ahead as planned and the dose of botox into the medial rectus and lateral rectus muscles was sufficient to cause substantial dampening of the horizontal pendular oscillations, but they were not completely stopped. Immediately following, the patient had partial ptosis and diplopia but nevertheless was pleased with the result and she was willing to patch the left eye to prevent diplopia to watch TV. Four weeks after the injection her visual acuity in the right eye had improved to 20/70, and in the uninjected left eye it remained at 20/200. The future botox treatment plan was to let the botox effect of the first set of injections wear off over three months and then reexamine her. At that time, a new injection strategy was to be planned to eliminate toxin spread to the levator palpebra superioris muscle and prevent the development of ptosis. Unfortunately, she was lost to follow up. See also: http://content.lib.utah.edu/cdm/ref/collection/ehsl-shw/id/103 |
