1. Date of download: 6/1/2016 Copyright © 2016 McGraw-Hill Education. All rights reserved. Multiple sclerosis produces protean symptoms that wax and wane. A. A common early symptom of multiple sclerosis (MS) is transient blurred vision in one eye as a result of optic neuritis, inflammation of the optic nerve that occurs during the acute phase of an MS lesion. 1. Shining a light in the normal eye produces both direct and consensual pupillary constriction, but when the light is swung to the affected eye, both pupils dilate because the patient perceives a relative dimming of light intensity. This is referred to as a de-afferented pupil. At no time with a de-afferented pupil is there anisocoria. A positive "swinging flashlight test" indicates a de- afferented pupil. 2. To determine the site of the lesion the examiner must use an ophthalmoscope to evaluate the possibility of a corneal or lenticular opacity, vitreous hemorrhage, retinal detachment, or ischemic retinopathy. 3. If the funduscopic examination is normal, or reveals a slight elevation or blurring of the optic nerve head, the lesion is localized to the visual pathway behind the eye. Lack of a homonymous visual field defect involving the other eye localizes the lesion proximal to the optic chiasm, therefore placing the lesion in the retrobulbar segment of the optic nerve consistent with the diagnosis of optic neuritis. B. The condition known as internuclear ophthalmoplegia (INO) is frequently the result of MS. The patient complains of double vision. 1. The patient attempts to visually follow a finger moving from side to side. The abducting eye follows but the adducting eye fails to track past the midline. The abducting eye may demonstrate nystagmus. The possibility of a lesion involving the oculomotor nucleus (N. III) is tested by examining convergence. The patient looks at the target finger placed directly in front and follows as the finger is brought toward the patient's nose. Normal adduction during convergence rules out a lesion of the nerve or nucleus. Additionally, the pupils will be observed to constrict as a result of the near response. 2. INO indicates a lesion of the medial longitudinal fasciculus (MLF), the white matter tract that links the third nerve (oculomotor) nucleus in the midbrain with the sixth nerve (abducens) nucleus in the pons to coordinate lateral gaze. Because these tracts are crossed and near the midline, most cases of INO are bilateral. C. As the result of an MS plaque involving the posterior columns of the cervical cord, patients may experience an electric shock-like sensation traveling down the spine and possibly into the limbs when the examiner flexes the neck (L'hermitte sign). Because MS is a disease of central white matter, lesions may cause upper motor neuron signs, such as brisk reflexes or a Babinski sign. Legend : From: The Neurological Examination of the Patient Principles of Neural Science, Fifth Editon, 2012 From: The Neurological Examination of the Patient Principles of Neural Science, Fifth Editon, 2012