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| A Peer Reviewed Publication of the College of Allied Health & Nursing at Nova Southeastern University | ||||||||||||||||||||
Sherrol A. Reynolds, O.D.
Citation:
Introduction There is no specific test for Multiple sclerosis (MS). However, the ophthalmic features of this disease may contribute to its correct diagnosis. Bilateral internuclear ophthalmoplegia (BINO) (see video clip) is one of the most common oculomotor complications of MS and one of the most frequent ways that the disease is manifested.4 Smith and Cogan found that out of 29 cases of BINO, 96% were ultimately diagnosed with MS.3 BINO has been considered to be “pathognomonic” for this disease.6 MS can cause other visual, neurological, and psychiatric impairments that can have a significant impact on the patient’s quality of life. Therefore, it is essential that an interdisciplinary team of health professionals be involved in the diagnosis and management of this disease. Case Report A 57 year-old Caucasian female presented with a complaint of decreased near vision in both eyes. She also reported a long-standing history of headaches that were relieved by Tylenol. Her past medical history was positive for severe chronic obstructive pulmonary disease and prior hospitalization for pneumonia and chronic bronchitis. Her social history was positive for smoking one pack of cigarettes per day for approximately forty years. She presented with a slight left head tilt. In addition, the patient's gait appeared to be unsteady and she was significantly underweight. She reported weighting only 75-pounds, with a gradual weight loss over the past ten years.
Best-corrected visual
acuity was 20/40 right eye and 20/40 left eye. Pupils were equal and
reactive with no afferent defect. Ocular motility testing revealed
bilateral adduction lag with an associated abduction nystagmus in the fellow
eye. Slowed abduction saccades and a right hypertropia were also observed.
Confrontation visual field testing and anterior segment evaluation were
unremarkable. Dilated fundoscopy revealed grade I nuclear sclerotic
cataracts in each eye. Examination of the right optic nerve revealed mild
temporal pallor (Figure I). The temporal aspect of the left optic nerve
exhibited a greater degree of pallor (Figure II). The macule and retinal
vasculature were normal in each eye.
Additional in office neurological testing revealed a
positive bilateral Babinsky (upward toe sign, The patient was referred to her primary care physician for a complete physical examination and additional ancillary testing. Laboratory testing, including CBC, SMA-12, B12, folate and thyroid profile yielded unremarkable findings. A neurology consult was also requested. Neurological evaluation revealed a broad-based ataxic gait and abnormal visual evoked and brain stem auditory evoked potentials. Magnetic resonance imaging (MRI) of the brain revealed numerous areas of punctate signal intensity consistent with demyelinating plaques involving the pons, mid-brain, cerebellum, and cerebral hemispheres (Figure III). The neuro-ophthalmic findings of BINO and optic nerve pallor, coupled with the ataxic gait, abnormal visual and brain stem auditory evoked potentials, and MRI plaques supported a diagnosis of multiple sclerosis. Due to her age of onset of the neurological symptoms from this disease, she was given a poor neurological prognosis.
Discussion BINO is caused by demyelinating lesions within the medial longitudinal fasciculus (MLF) in the region between the third and sixth nerve nuclei.3-4, 8, 26 The MLF consists of fibers that carry conjugate horizontal eye movement signals from the sixth nerve nuclei to the contralateral third nerve nuclei. The MLF also consists of fibers for maintaining steady vertical position. Areas of demyelination compromise the neurological signal in the MLF, which leads to the clinical features of BINO; bilateral palsy of adduction on attempted horizontal gaze, bilateral horizontal nystagmus of the abducting eye, and a vertical gaze-evoked nystagmus (Figure IV). 4, 20 The impaired adduction on attempted horizontal gaze may be complete, where the eye does not move pass the mid-point, or partial, where the eye either incompletely adducts or adducts slower than normal in speed.
BINO is considered pathognomonic for MS because there is a strong predilection for the demyelinating lesions of MS to affect the MLF.3-6However, it remains unsatisfactorily explained in the literature why this predilection for the MLF occurs. While BINO is considered pathognomonic for MS, other etiologies are possible and should be considered in cases not consistent with a diagnosis of MS. Common causes of BINO are listed in Table I. 23-25
BINO can occur as an isolated finding or coincidentally with other ocular manifestations of MS. Various ocular findings possible in MS patients are listed in Table II. 3-4,15,16 Other neurological and psychiatric complications may precede, occur concurrently with, or follow the development of BINO. A positive Babinski reflex is a common neurological sign that occurs with BINO.12 Smith and Cogan found that 45% of patients with BINO had a positive Babinski’s reflex, which reveals upper motor neuron lesions in these patients.3 Other symptoms of MS, including paraesthesia of the extremities, weakness of the limbs and face, vertigo, ataxia, disturbance of micturation, fatigue and depression, may occur with BINO.1, 3-5, 8-10,15
Prognosis: BINO occurs equally in men and women, and at any age in MS patients. Patients with BINO have an ocular prognosis that is as unpredictable as the MS disease itself.4, 7 In some cases, BINO may resolve in a matter of days to weeks, while in others it can become recurrent and even permanent. The majority of BINO patients have no symptoms, but for those with double vision, prismatic spectacle correction may be beneficial. Patients who are older at the onset of BINO and exhibit multiple symptoms of MS generally have a worse neurological prognosis due to the deterioration of motor function.7, 27 Multiple Sclerosis Association MS is a slowly progressive disease of unknown etiology. The disease occurs more commonly in women than men by a ratio of 2:1.32 There are three types of MS: the benign, relapsing-remitting, and progressive types. Patients with the benign type have complete or nearly complete resolution of symptoms. The majority of patients have the relapsing-remitting type. It is characterized by an unpredictable period of exacerbation and remission of neurological symptoms. The progressive type occurs in the later stage of the disease and is characterized by a gradual development of neurological problems. Patients with this type of MS generally have a poor prognosis due to the accumulating degree of disability. There is no specific treatment that halts the progression of MS. Therapeutic management known as disease-modifying therapies (DMT) are used during different aspects of MS. The three main classes of drugs used to treat MS are immunosuppressives, steroids, and interferons. Each has significant side effects that limit their use.21The only drug class that has been shown to reduce the frequency and severity of relapses over time in MS patients, while having limited side effects, is the Interferon-beta drugs. The only medications proven effective for the ocular manifestations of MS are intravenous methylprednisone with a tapering course of oral prednisone, which is used specifically for the demyelinating optic neuritis.10, 15, 31 MS is one of the most common causes of visual, neurological, and psychiatric impairment in North America.8 The disabling symptoms of this complex disease can prevent the patient from performing various daily activities and responsibilities. The disease can interfere with the patient’s cognitive abilities, family life, social life, emotional outlook, occupation or a combination of these.28-30 A few of these symptoms may be improved with pharmacological therapy. However, effective management of the many and varied complications of MS requires an interdisciplinary team approach. The primary care physician, neurologist, eye care physician, physician assistant, pharmacist, nurse, physical therapist, occupational therapist, and mental health specialist should all be involved in the management team. Conclusion BINO and other neuro-ophthalmic complications are important clinical findings that may help establish a diagnosis of MS. In some cases, patients may overlook other neurological signs, until a visual symptom develops. Therefore, all health care providers should be aware of the ocular signs of this disease. The allied health professional plays an important role in the diagnosis and management of MS. The many and varied disabling complications of MS can have a significant effect on the quality of life for patients with this disease. It is essential that an interdisciplinary team of health care professionals be involved in the comprehensive care of patients living with MS. References 1. Leibowitz U, Alter M. Optic nerve involvement and diplopia as initial manifestation of multiple sclerosis. Acta Neurol. Scand 1968;44:70-80 2. Kuroiwa Y, Shibasaki H. Clinical studies of multiple sclerosis in Japan. A current appraisal of 83 cases. Neurology 1973;23:609-617 3 Smith JL, Cogan DG. Internuclear Ophthalmoplegia, A Review of Fifty-Eight Cases. Arch Ophthal 1959;61:687-694 4. Cogan DG. Internuclear Ophthalmoplegia, Typical and Atypical. Arch Ophthal 1970;84:583-589 5. Goynea EF. Bilateral internuclear ophthalmoplegia: Association with occlusive cerebrovascular disease. Arch Neurol. 1974;31:168-173 6. Harris W. Ataxic nystagmus: A Pathognomonic Sign in Disseminated Sclerosis. Brit J. Ophth 1944;28:40 7. Midgard R, Albrektsen G, Rise T, Kvale G, Nyland H. Prognostic factors for survival in multiple sclerosis: A longitudinal, population based study in More and Romsdal, Norway. J Neurol Neurosurg Psyciatr 1995;58:417-421 8. Kaufman DI, Fratkin J. Multiple Sclerosis and the Eye. 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