A case of midbrain infarction mainly presenting Nothnagel syndrome with various eye movement disorders

Cerebellar ataxia with either unilateral or bilateral involvement of the oculomotor nerve due to a midbrain lesion in the brain stem is called Nothnagel's syndrome. We report on a 68-year-old man who presented with typical Nothnagel's syndrome. Neurological examinations revealed a left cerebellar ataxia associated with oculomotor and trochlear palsies and an eccentric and oval pupil in the right eye. There was a vertical and lateral gaze paresis in the left eye. Transient involuntary movement of the left leg suggested that the lesion involved the red nucleus. Cranial MRI scans revealed an infarct extending from the dorsal paramedian region of the right midbrain tegmentum to the medial side of the thalamus. These findings suggest that the contralateral oculomotor palsy in this patient was caused by dysfunction of the neural complex in the midbrain tegmentum, riMLF, the interstitial nucleus of Cajal, the posterior commissure and desending fibers from the superior colliculus to the paramedian pontine reticular formation and the Edinger-Westphal nucleus.