Isolated ophthalmoplegia of abduction.

A case of transient complete bilateral paresis of abduction is reported without esotropia. Loss of vestibular ocular reflex (VOR) responses of the abducting eye and intactness of all other slow VOR reactions were the leading symptoms. Since bilateral lesions of the pontine gaze centers in this initially comatose patient without signs of increased intracranial pressure were excluded, bilateral lesions of the abducens nerves appeared improbable. In view of normal function of the ascending tract of Deiters bilateral paramedian lesions between the vestibular and abducens nuclei appeared to be more likely. Clinical course with relatively rapid recovery after administration of thiamine, theoretical considerations, and some earlier reports led to the conclusion that in some metabolic-toxic disorders--apparently in this case of Wernicke's encephalopathy--intrapontine connections in the paraabducens area may be selectively vulnerable. A similar effect on oligosynaptic connections to the medial rectus nucleus could lead to a disordered inhibition of this muscle. The term "posterior INO of Lutz" should no longer be used because of the lack of any anatomical and physiological evidence for its existence.