Pseudo-Internuclear Ophthalmoplegia

Pseudo-Internuclear Ophthalmoplegia

Pseudo-internuclear ophthalmoplegia is a disorder of eye movements with impaired adduction in one eye and horizontal nystagmus in the abducting eye (i.e., signs as in an internuclear ophthalmoplegia) but without an intrinsic brainstem lesion. This sign may be seen in:

Myasthenia gravis (a diagnosis which is always worthy of consideration in a patient with an "isolated INO") due to extraocular muscle weakness
Brainstem compression due to subdural hematoma with transtentorial herniation
Cerebellar mass lesion
Guillain-Barré syndrome, Miller Fisher syndrome Thyroid ophthalmopathy
Orbital pseudotumor.

Cross References

Internuclear ophthalmoplegia (INO); One-and-a-half syndrome