Internuclear ophthalmoplegia
From Wikipedia, the free encyclopedia
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| Schematic demonstrating right internuclear ophthalmoplegia, caused by injury of the right medial longitudinal fasciculus. | |
| ICD-10 | H51.2 |
| ICD-9 | 378.86 |
| DiseasesDB | 6853 |
Internuclear ophthalmoplegia is a physical finding, or sign, that is a particular form of ophthalmoparesis. It can affect either the right or left eye. It is a disorder of conjugate lateral gaze. The affected eye shows impairment of adduction. The partner eye diverges from the affected eye during abduction, producing diplopia; during extreme abduction, compensatory nystagmus can be seen in the partner eye.
[edit] Causes
The disorder is caused by injury or dysfunction in the medial longitudinal fasciculus, a tract that allows conjugate eye movement by connecting the abducens nucleus of one side to the occulomotor nucleus of the opposite side. The unaffected eye will point away from the lesioned side.
Causes are manifold; brainstem demyelinating diseases such as multiple sclerosis are frequently found to be causal, and should be considered especially if no other abnormalities are discovered by examination or brain imaging, especially in younger patients. In older patients a stroke is another possibility. In the case of a bilateral internuclear ophthalmoplegia multiple sclerosis is almost certain to be the cause given that a bilateral stroke is unlikely.
