[Unilateral paresis of the fourth cranial nerve as the only symptom of mesencephalic ischemia].

INTRODUCTION

Lesions of the fourth cranial nerves are infrequently diagnosed in cases of disorder of the oculomotor nerves. Most authors consider head injury to be the usual cause of this lesion, which is also frequently seen in association with a microvascular lesion in persons with blood flow problems.

CLINICAL CASE: We present the case of an isolated lesion of the trochlear nerve as a consequence of midbrain ischaemia.

CONCLUSIONS

Vascular disorders of the brain stem are an uncommon cause of paresis of the superior oblique muscle of the eye and exceptional as the only symptom.