J Korean Neurosurg Soc.  2013 Mar;53(3):194-196. 10.3340/jkns.2013.53.3.194.

Dissecting Aneurysm of Vertebral Artery Manifestating as Contralateral Abducens Nerve Palsy

• Jeon JS
• Lee SH
• Son YJ
• Chung YS

• KMID: 2190764
• DOI: http://doi.org/10.3340/jkns.2013.53.3.194

Abstract

Isolated abducens nerve paresis related to ruptured vertebral artery (VA) aneurysm is rare. It usually occurs bilaterally or ipsilaterally to the pathologic lesions. We report the case of a contralateral sixth nerve palsy following ruptured dissecting VA aneurysm. A 38-year-old man was admitted for the evaluation of a 6-day history of headache. Abnormalities were not seen on initial computed tomography (CT). On admission, the patient was alert and no signs reflecting neurologic deficits were noted. Time of flight magnetic resonance angiography revealed a fusiform dilatation of the right VA involving origin of the posterior inferior cerebellar artery. The patient suddenly suffered from severe headache with diplopia the day before the scheduled cerebral angiography. Neurologic examination disclosed nuchal rigidity and isolated left abducens nerve palsy. Emergent CT scan showed high density in the basal and prepontine cistern compatible with ruptured aneurismal hemorrhage. Right vertebral angiography illustrated a right VA dissecting aneurysm with prominent displaced vertebrobasilar artery to inferiorly on left side. Double-stent placement was conducted for the treatment of ruptured dissecting VA aneurysm. No diffusion restriction signals were observed in follow-up magnetic resonance imaging of the brain stem. Eleven weeks later, full recovery of left sixth nerve palsy was documented photographically. In conclusion, isolated contralateral abducens nerve palsy associated with ruptured VA aneurysm may develop due to direct nerve compression by displaced verterobasilar artery triggered by primary thick clot in the prepontine cistern.

Keyword

Vertebra artery; Subarachnoid hemorrhage; Abducens nerve paralysis

MeSH Terms

Abducens Nerve
Abducens Nerve Diseases
Aneurysm
Aneurysm, Dissecting
Angiography
Arteries
Brain Stem
Cerebral Angiography
Diffusion
Dilatation
Diplopia
Follow-Up Studies
Headache
Hemorrhage
Humans
Magnetic Resonance Angiography
Magnetic Resonance Imaging
Muscle Rigidity
Neurologic Examination
Neurologic Manifestations
Paresis
Subarachnoid Hemorrhage
Vertebral Artery

Figure

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  Fig. 1 A and B : TOF-MRA and axial MRA source images revealing a fusiform dilatation of the right vertebral artery. C and D : Emergent CT scan demonstrates thick cisternal hemorrhage, in particular prepotine cistern without ventriculomegaly. TOF : time of flight.

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  Fig. 2 A and B : Right vertebral angiography shows a dissecting aneurysm of the vertebral artery (white arrow) including origin of the PICA with prominent flexed and displaced vertebrobasilar artery (white arrowheads). Blood supply to left proximal PICA through glomus-like vascular channel (black arrow) from right VA is observed. C : No diffusion restriction of brainstem is found. D : Follow-up angiography illustrates the upward migration of vertebrobasilar artery (white arrowheads). E : Resolution of hemorrhage is noted in the prepontine cistern. PICA : posterior inferior cerebellar artery, VA : vertebral artery.

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  Fig. 3 A : Initial photograph discloses isolated unilateral sixth nerve palsy on left side. B : A photograph taken 11 weeks later revealed the recovery of left abducens nerve palsy.

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