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Anatomy of Neck and Blood Supply of Brain
Published in Sudhir K. Gupta, Forensic Pathology of Asphyxial Deaths, 2022
The carotid arterial system and the vertebral arterial system (Figures 2.35 and 2.36) contribute to the arterial blood supply of the brain. Left and right common carotid arteries arise from arch of aorta and brachiocephalic trunk respectively. At the superior border of thyroid cartilage, external and internal carotid arteries arise from the common carotid arteries, with the internal carotid being more medially placed. The internal carotid artery in its intracranial course divides into anterior and middle a cerebral artery which provides the anterior cerebral circulation of brain. The posterior cerebral circulation is mainly by the vertebral arteries. Vertebral arteries traverse the foramen transversarium of cervical vertebra and enter the skull through the foramen magnum where they join to form the basilar artery and posterior cerebral arteries are their terminal branches.
Dizziness
Published in Henry J. Woodford, Essential Geriatrics, 2022
In older people, lightheadedness is a more frequent reason for complaining of dizziness than vertigo.1 The commonest cause of this symptom is transient cerebral hypoperfusion in relation to neurocardiovascular disorders (e.g. orthostatic hypotension, vasovagal syndrome and carotid sinus hypersensitivity). The presence of posterior cerebral circulation atheromatous disease may make this symptom more likely to occur. Lightheadedness unrelated to postural change may be caused by brainstem cerebrovascular disease, drugs or, occasionally, by paroxysmal cardiac arrhythmias or psychological disorders. An overall scheme for the assessment of lightheadedness is discussed later in Chapter 15 (seeFigure 15.6).
Cerebrovascular Diseases
Published in Amy J. Litterini, Christopher M. Wilson, Physical Activity and Rehabilitation in Life-threatening Illness, 2021
Amy J. Litterini, Christopher M. Wilson
Cerebrovascular diseases include diagnoses in which the blood vessels to the brain are deformed or damaged, affecting cerebral circulation. Cerebrovascular accidents (CVA), also commonly referred to as strokes, are life-threatening diagnoses affecting arteries that lead to the brain causing them to rupture or occlude (see Figure 12.1).1
Variability across countries for brain death determination in adults
Published in Brain Injury, 2023
Fang Yuan, Huiping Li, Tao Pan, Wanxin Wen, Lixin Wang, Shibiao Wu
Somatosensory evoked potentials (SEPs) test examines lemniscal pathways in the hemispheres and brainstem, and it was reported to be a reliable test for brain death determination with a sensitivity of 87.4%-100% (18–20). The examination of cerebral circulation provides an alternative evaluation of brain function. TCD is recognized as one of the three confirmatory tests in Chinese criteria of brain death. However, TCD is reported to a lower sensitivity (73%-78%) than EEG and SEPs (19,21). The diagnostic performance of ancillary tests may vary depending on the criteria of brain death in different countries, but our study suggests that such differences are small. Although we reported a higher sensitivity of 84.3%-86.0% for TCD, our finding that EEG and SEP have higher sensitivities than TCD is consistent with previous studies (19,21). Therefore, the results of EEG and SEP results should be given more weight than TCD, whether in China, USA, or Europe. Besides, TCD is limited by the penetrability of transtemporal windows and interexaminer variability. MR and CT angiography were proposed to assist brain death determination (22,23). However, angiography requires higher cost and the transfer of patients out of intensive care unit which generates potential safety hazards.
Managing complications after transcatheter aortic valve implantation
Published in Expert Review of Medical Devices, 2022
Giuliano Costa, Claudia Reddavid, Elena Dipietro, Marco Barbanti
Management of stroke episodes in the elderly TAVI population is still a matter of debate due to the inherent frailty and high bleeding risk of this subset of patients. A recent analysis of US practice showed that the vast majority of patients experiencing stroke after TAVI are treated with medical therapy and showed an in-hospital mortality of about 8%. Besides, a minority of patients (less than 10%) are treated with thrombolytics or mechanical thrombectomy but showed worse outcomes (up to 22% of in-hospital mortality) [89]. Due to the poor prognosis of procedural-related cerebrovascular accidents, efforts have been focused on the possibility to prevent such events. In this view, in the last years different cerebral embolic protection devices (CEPD) have entered the market and have been increasingly used worldwide (Table 3). These devices work by filtering or deflecting the debris away from the cerebral circulation while allowing ongoing cerebral perfusion. Despite their rationale, the clinical benefit of their use has been mainly showed in observational trial, with ad-hoc RCTs that have failed to demonstrated a significant reduction of stroke in patients receiving a CEPD [90]. In the SENTINEL Trial embolic debris was captured in 99% of patients that received the Sentinel CEPD (Claret Medical, Santa Rosa, California), with a 42% reduction in new lesion volume on diffusion-weighted MRI (DW MRI) compared to patients not receiving the CEPD. However, stroke rates did not statistically differ between patients receiving or not the CEPD (5.6% vs. 9.1%, p = 0.25) [91].
Ocular ischaemia: signs, symptoms, and clinical considerations for primary eye care practitioners
Published in Clinical and Experimental Optometry, 2022
Michael Kalloniatis, Henrietta Wang, Paula Katalinic, Angelica Ly, Warren Apel, Lisa Nivison-Smith, Katherine F Kalloniatis
Cerebral circulation is maintained through an efficient blood supply involving the carotid and vertebral arteries and anastomoses forming the Circle of Willis. The sequelae of impaired cerebral circulation leads to transient ischaemic attacks (TIA) or completed strokes: both events are serious medical conditions. Based on the Classification and Outline of Cerebrovascular Diseases II,7 completed strokes are defined as prolonged neurological deficit that are relatively stable with a duration of over three weeks. On the other hand, TIAs were previously defined as brief episodes of focal cerebral ischaemia lasting less than 24 hours and not associated with a permanent infarct.8 Studies showed that 30-50% of the TIAs within the 24-hour time frame had brain injury in MRI studies and a new definition was developed: ‘a brief episode of neurological dysfunction caused by focal brain or retinal ischemia, with clinical symptoms typically lasting less than one hour, and without evidence of acute infarction’.9–11 However, even the new proposed definition had a one-hour time frame and may not accurately distinguish between patients with or without acute cerebral infarction and thus the writing committee endorsed the revised definition for a TIA as ‘a transient episode of neurological dysfunction caused by focal brain, spinal cord, or retinal ischemia, without acute infarction’.11 Based upon the new TIA definition, an ischaemic stroke is ‘an infarction of central nervous system tissue’.11 Unlike TIAs, ischaemic strokes may be symptomatic or silent.