Isolated central acute vestibular syndrome following nucleus prepositus hypoglossi infarction

Abstract

Isolated vertigo following lesions to the nucleus prepositus hypoglossi is extremely rare. Herein, we report a patient who presented with isolated central acute vestibular syndrome. Magnetic resonance imaging (MRI) revealed acute infarction involving the isolated nucleus prepositus hypoglossi in the dorsal medial medulla oblongata and pons. The case illustrates that isolated acute vestibular syndrome can be caused by a rare nucleus prepositus hypoglossi infarction. A 60-year-old woman who presented with sudden-onset vertigo and unsteadiness was referred to our neurological ward. She had a medical history of hypercholesterolemia, Type 2 diabetes mellitus, ischemic stroke and coronary artery disease. On admission, her blood pressure was 200/96 mmHg and heart rate was 86 beats/min. She was in agony with closed eyes and presented with frequent nausea and vomiting in response to slight head movements. The neurological examination disclosed prominent, spontaneous, left beating nystagmus with torsional and a horizontal component. The left beating nystagmus was more intense when she looked toward the left and converted to right beating nystagmus on rightward gaze. There were no sensory deficits and she had full limb function. Bilateral finger-to-nose and heel-to-shin tests revealed no motor incoordination or dysmetria on either side. Her gait could not be evaluated due to the severe vestibular symptoms. Bilateral Babinski signs were positive. Urgent computed tomography (CT) showed lacunar infarctions in the bilateral basal ganglia, brainstem and white matter around the lateral ventricle. Acute vestibular syndrome (AVS) was considered in a differential diagnosis that also included vestibular neuronitis, Ménière’s disease and posterior circulation stroke. An MRI of the brain performed 24 h after admission was reported to be unremarkable. However, closer review of the imaging revealed an acute ischemic infarct in the dorsal brainstem with restricted diffusion on diffusion-weighted imaging (DWI). This selectively involved the nucleus prepositus hypoglossi (NPH) in the dorsal medial medullary oblongata and pontine (Fig. 1). After throughout analysis, the presumed stroke mechanism was small vessel disease. The patient was treated with 100 mg aspirin, 75 mg clopidogrel, and 40 mg atorvastatin daily. Treatment alleviated the vertigo and nystagmus and at 2 weeks after admission she had only mild unsteadiness while walking. Unfortunately, no video data were obtained on her first neurological examination due to our late awareness of the importance of the case. In addition, electronystagmography (ENG) could not be performed until 10 days after admission due to patient’s severe vertigo. By this point, the nystagmus * Yi Sui [email protected]