Isolated rotational nystagmus may be the only clue to the early diagnosis of dorsolateral medullary infarction.

The medulla contains complex nervous structures related to motor, sensory, coordination, and visceral autonomic functions. The medullary infarctions cause various symptoms and signs depending on the location of the lesion. Lateral medullary infarction is caused by a vascular event in the territory of the posterior inferior cerebellar artery or the vertebral artery. We report a case of a patient with falling tendency and whirling sensation. He reported no facial drop, arm drift, slurred speech, difficulty of swallowing, or weakness of his limbs. The neurologic examination revealed no decreased muscle power, dysarthria, dysphagia, or other relevant neurologic deficits. Urgent noncontrast brain computed tomography detected no acute hemorrhage or ischemic lesion. On admission, the oculomotor examination revealed conjugated rotational nystagmus with clockwise direction. The magnetic resonance imaging of the brain demonstrated acute infarct in the medulla oblongata approximately 0.8 × 0.5 cm. The infarct appears bright on diffusion-weighted images (Fig.). A diagnosis of dorsolateral medulla infarction was established, and the patient was started on a therapy of 100 mg aspirin once daily. After standard therapies, the patient's recovery was uneventful.