Nizam Ahmad, Yacoub Hussam A, McKinney James S
Department of Neurology, UMDNJ-Robert Wood Johnson Medical School, Piscataway, NJ, USA.
Neurologist. 2011 Nov;17(6):333-7. doi: 10.1097/NRL.0b013e318218030a.
Acute oculomotor nerve (CN III) palsies are commonly attributed to microvascular disease or compressive lesions and aneurysms, but may rarely be associated with ischemic large vessel disease. We report a case of an extracranial internal carotid artery (ICA) dissection heralded by CN III palsy with review of the relevant literature.
A 24-year-old right-handed man presented with right-sided weakness preceded by vomiting 2 days earlier. The following day, the family noted his left eye to be deviated outward with enlarged pupil and droopy eyelid. On the day of admission, he had a fall owing to right-sided weakness. His neurological examination revealed significant aphasia, left third nerve palsy, right homonymous hemianopsia, and right-sided hemiplegia with hemisensory deficits. A brain magnetic resonance image showed an acute ischemic infarct in the left middle cerebral artery distribution without mass effect. Magnetic resonance angiogram showed a left extracranial internal cerebral artery (ICA) dissection with absence of flow within the distal cervical and intracranial ICA segments. He underwent a decompressive left hemicraniectomy with partial improvement in his deficits.
Oculomotor nerve palsy as a result of ICA disease is a rare entity but has been reported in cases of stenosis, occlusion, and dissection. It is likely to be caused by hypoperfusion of CN III secondary to low flow or microembolism in the arteries feeding the nerve. The risk of CN III palsy in patients with ICA disease is higher in the presence of a fetal posterior cerebral artery.
Acute oculomotor nerve palsies with pupillary involvement warrant thorough investigation. When routine work-up fails to elucidate an etiology, extracranial carotid pathology should be considered.
急性动眼神经（CN III）麻痹通常归因于微血管疾病、压迫性病变和动脉瘤，但很少与缺血性大血管疾病相关。我们报告一例以CN III麻痹为先兆的颅外颈内动脉（ICA）夹层，并对相关文献进行回顾。
一名24岁右利手男性，2天前出现呕吐，随后出现右侧肢体无力。次日，家属发现他左眼向外偏斜，瞳孔扩大，眼睑下垂。入院当天，他因右侧肢体无力摔倒。神经系统检查显示明显失语、左侧动眼神经麻痹、右侧同向性偏盲以及右侧偏瘫伴半身感觉障碍。脑部磁共振成像显示左侧大脑中动脉分布区急性缺血性梗死，无占位效应。磁共振血管造影显示左侧颅外颈内动脉（ICA）夹层，颈段和颅内ICA远端节段无血流信号。他接受了左侧去骨瓣减压术，症状部分改善。
ICA疾病导致的动眼神经麻痹是一种罕见情况，但在狭窄、闭塞和夹层病例中均有报道。可能是由于供应该神经的动脉低流量或微栓塞继发CN III灌注不足所致。在存在胎儿型大脑后动脉的情况下，ICA疾病患者发生CN III麻痹的风险更高。
伴有瞳孔受累的急性动眼神经麻痹需要进行全面检查。当常规检查未能明确病因时，应考虑颅外颈动脉病变。
