OVERVIEW
Internuclear ophthalmoplegia, also known as medial longitudinal fasciculus syndrome, is a paralysis of horizontal isotropic movements of the eyeball caused by damage to the medial longitudinal fasciculus, and is common in cerebrovascular disease and multiple sclerosis. Treatment is determined by the etiology.
Etiology
Anterior internuclear ophthalmoplegia is located in the midbrain and involves the upstream fibers of the bundle, showing normal contraction of the rectus externus muscle and incomplete contraction of the rectus internus muscle during isotropic lateral gaze, monocular horizontal nystagmus of the abducting eye is outwardly directed in a fast phase, and the incompletely contracted rectus internus muscle has normal movement when gazing at a near object, and the posterior internuclear ophthalmoplegia is located in the pontine brain and involves the lower fibers of the bundle, showing normal contraction of the rectus internus muscle and incomplete contraction of the rectus externus muscle during lateral gaze, and the anterior chamber reflex proves not to be the cause. Incomplete contraction of the rectus medialis muscle during lateral gaze and contraction of the rectus externus muscle is not seen.
It is common in cerebrovascular disease and multiple sclerosis, and is occasionally an early symptom of brainstem tumors.
Differential diagnosis
1. Anterior internuclear oculomotor palsy
It is manifested by the inability of the affected eye to retract when both eyes gaze to the opposite side of the lesion, and nystagmus accompanied with normal convergence reflex when the contralateral eyeball is abducted. Due to the damage of bilateral medial longitudinal fasciculus, both eyes could not retract internally.
2. Posterior internuclear oculomotor palsy
The lesion is located in the medial longitudinal fasciculus downstream fibers between the pontine lateral ventricular center and the spreading nerve, manifesting as the affected side of the eyeballs can not be abducted when both eyes look to the same side of the lesion, the opposite side of the eyeballs inwardly normal, the affected side of the stimulation of the vestibule can be a normal abduction movement, and the convergence reflex is normal.
3. One and a half syndrome
The symptom is that the affected eyeball can neither be adducted nor abducted when gazing horizontally, and the contralateral eyeball can neither be adducted nor abducted when gazing horizontally, but there is horizontal nystagmus.
Examination
Ophthalmologic examination: when the patient gazes at the long strip on the rotating drum, detached nystagmus occurs, the amplitude of one eye is obviously larger than that of the other eye, and when the target moves to the affected side, the amplitude of the contralateral eye is larger; when the target moves from the left side of the patient to the right side of the patient in case of bilateral nuclear interneuron palsy, then the nystagmus of the left eye will be obvious, and when the target moves from the right side to the left side of the patient, then the nystagmus of the right eye will be obvious.
Treatment principle
Treatment is determined according to the cause of the disease, and comprehensive measures are taken to improve cerebral microcirculation.