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Central nervous system lesions
Published in Ibrahim Natalwala, Ammar Natalwala, E Glucksman, MCQs in Neurology and Neurosurgery for Medical Students, 2022
Ibrahim Natalwala, Ammar Natalwala, E Glucksman
A 53-year-old lady is found having collapsed at home. On admission to hospital, she has a Glasgow Coma Scale score of 12 (Eye – 3, Speech – 4, Motor – 5). A post-contrast computed tomography (CT) scan of her head is performed, which demonstrates high attenuation in the sylvian fissures and the supra-sellar cistern. A CT angiogram demonstrates a large posterior communicating artery aneurysm.
Anatomy and Cerebral Circulation of the Rat
Published in Yanlin Wang-Fischer, Manual of Stroke Models in Rats, 2008
Yanlin Wang-Fischer, Ricardo Prado, Lee Koetzner
The posterior cerebral artery is a branch of the posterior communicating artery (Figure 4.4a). It curves around the peduncle of the cerebrum and runs upward along the fold of the tentorium to supply the surface of the hemisphere, including the medial and lateral surfaces of the occipital lobe.
Neurorescue During Carotid Stenting: Catheter-Based Techniques and Patient Management
Published in Peter A. Schneider, W. Todd Bohannon, Michael B. Silva, Carotid Interventions, 2004
Peter A. Schneider, Michael B. Silva
The worst outcome of episodes of cerebral embolization are associated with “T occlusions,” that is, occlusion of the distal internal carotid artery that extends into the M1 and A1 segments. The mortality in this setting is 50% to 90% (37–39). With more focal arterial occlusions, the specific location of the cerebral artery lesion is far more important than the tissue mass served by the occluded artery. A very small but well-placed infarction in the motor cortex may have much more severe sequelae than a much larger zone of infarction in the frontal or occipital lobes. When a significant neurological deficit occurs due to an embolus, the embolus is usually large enough to occlude a major cerebral artery (38, 40, 41). When an embolus lodges in a major cerebral artery, the vessel is usually patent distal to the embolus but with very slow or stagnant flow. If collateral perfusion is able to keep brain tissue alive long enough to perform thrombolysis, the results may be excellent (14). However, if end arteries are occluded, especially important ones like the lenticulostriate arteries, the likelihood of a good result is low. When a middle cerebral artery occlusion occurs, for example, the collateral blood supply is usually from the anterior cerebral artery through pial branches. The anterior cerebral artery usually receives collateral blood supply from the contralateral anterior cerebral artery through the anterior communicating artery. The posterior cerebral artery receives blood supply through the posterior communicating artery. A focal, proximal occlusion with good collaterals may be less threatening than a smaller, more distally placed embolus to an area with no collateral perfusion. If thrombus is instrumented aggressively enough to break it up without dissolving it, multiple distal branches may become occluded. In summary, when an occlusion occurs, the clinical significance may vary from none to profound, based on the location of the occlusion and underlying collateral pathways (both major cerebral arteries and pial collaterals).
Neuro-Ophthalmic Literature Review
Published in Neuro-Ophthalmology, 2022
David A. Bellows, Noel C.Y. Chan, John J. Chen, Hui-Chen Cheng, Peter W MacIntosh, Jenny A. Nij Bijvank, Michael S. Vaphiades, Xiaojun Zhang
The authors described a 73-year-old man who developed a left complete, pupil-sparing third cranial nerve palsy who was found to have a paraclinoid meningioma in the left cavernous sinus. As compressive lesions are expected to impair the iris sphincter muscle, no intervention was recommended and the palsy spontaneously improved within 3 months indicating a vasculopathic nature. They also described a 54-year-old woman with diabetes and a complete third nerve palsy with a dilated, nonreactive pupil. Initial CTA was reported as normal, but a re-review of imaging revealed a posterior communicating artery aneurysm and immediate intervention to coil the aneurysm occurred. The authors concluded that the “Rule of the Pupil” is still important in the modern neuroimaging era as demonstrated in their cases of incidentally found lesions along the course of the oculomotor nerve and missed radiological findings, respectively.
Atypical junctional scotoma secondary to optic chiasm atrophy: a case report
Published in Clinical and Experimental Optometry, 2019
Historical studies of the extrinsic blood supply to the optic chiasm have reached different conclusions.2018 A very recent study aimed to resolve these discrepancies in blood supply to different parts of the optic chiasm using human cadaver eyes.2018 They concluded that the optic chiasm is supplied by all arteries of the circle of Willis.2018 Specifically, the superior hypophyseal arteries and posterior communicating artery supply the inferior side of the optic chiasm, while the first segment of the anterior cerebral artery, superior hypophyseal artery, anterior communicating artery, and the posterior communicating artery supplied the superior side of the optic chiasm.2018 This anatomical consideration is important in this case, as the ischaemic lesion responsible for the patient's visual field defects localise to the same chiasm areas that the first segment of the anterior cerebral artery and anterior communicating artery supply.2018
Improved visual acuity after microsurgical clipping of a symptomatic anterior cerebral artery aneurysm: case report
Published in British Journal of Neurosurgery, 2019
Fatih Arcan, Andreas W. Unterberg, Klaus Zweckberger
Intracranial aneurysms occur in most cases (about 85%) within the anterior circulation. Despite the proximity to nervous structures (optic nerve, chiasm, oculomotor nerve), visual symptoms are rare. According to the anatomical configuration, visual deterioration might occur due to direct pressure caused by the aneurysm dome or by adhesions following hemorrhages or mechanical irritation of the nerve. In most cases, visual symptoms, such as blindness or unilateral scotoma, are slowly progressing with increasing size of aneurysm. Furthermore, the variable nature of visual symptoms which is underlying spontaneous fluctuation is not fully understood but presumably due to factors like arterial micro-vasospasm or shifting of nervous structures.1 While posterior communicating artery aneurysms cause oculomotor deficits, aneurysms compressing the optic nerve, and thus causing blindness, are exceptional and preponderantly lacking in the literature. Furthermore, it is under debate, whether operative clipping or endovascular coiling might be the best treatment of choice for symptomatic aneurysms.