INTRODUCTION: An oculomotor palsy in the setting of aneurysmal subarachnoid hemorrhage is often due to compression by a posterior communicating artery aneurysm. Anterior communicating artery (ACOM) aneurysms may produce ophthalmologic symptoms of the anterior visual pathways, but rarely ever lead to a 3rd nerve palsy. This report describes a rare case of an isolated oculomotor palsy in a patient who experienced subarachnoid hemorrhage from an ACOM aneurysm. CLINICAL PRESENTATION: A 46-year-old male presented to the emergency department with headache, emesis, and an isolated left third nerve palsy-the remainder of his exam was normal. A head CT showed diffuse subarachnoid hemorrhage that was later attributed to an ACOM aneurysm as determined by angiography. INTERVENTION: Due to the configuration of the aneurysm, it was not deemed treatable by endovascular means. Following a successful clipping, the patient experienced a delayed, transient, monocular visual loss. Upon follow-up, his oculomotor palsy had completely resolved. CONCLUSION: In very rare circumstances, an ACOM aneurysm may produce an isolated third nerve palsy. The etiology of the palsy is likely related to clot formation and/or irritating blood products.
INTRODUCTION: An oculomotor palsy in the setting of aneurysmal subarachnoid hemorrhage is often due to compression by a posterior communicating artery aneurysm. Anterior communicating artery (ACOM) aneurysms may produce ophthalmologic symptoms of the anterior visual pathways, but rarely ever lead to a 3rd nerve palsy. This report describes a rare case of an isolated oculomotor palsy in a patient who experienced subarachnoid hemorrhage from an ACOM aneurysm. CLINICAL PRESENTATION: A 46-year-old male presented to the emergency department with headache, emesis, and an isolated left third nerve palsy-the remainder of his exam was normal. A head CT showed diffuse subarachnoid hemorrhage that was later attributed to an ACOM aneurysm as determined by angiography. INTERVENTION: Due to the configuration of the aneurysm, it was not deemed treatable by endovascular means. Following a successful clipping, the patient experienced a delayed, transient, monocular visual loss. Upon follow-up, his oculomotor palsy had completely resolved. CONCLUSION: In very rare circumstances, an ACOM aneurysm may produce an isolated third nerve palsy. The etiology of the palsy is likely related to clot formation and/or irritating blood products.