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Query: UMLS:C0022116 (ischemia)
 91,303 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Posture changes may cause hemodynamic ischemic events, particularly in severe vertebrobasilar artery disease. It may be difficult and not without risk to prove this vulnerability to changes in posture during angiography. Therefore, TCD monitoring with passive tilting (PT) was used to evaluate cerebral hemodynamics distally to severe bilateral vertebral artery disease (BVAD). PCA flow velocity changes and dynamic cerebral autoregulation (DCA) were analyzed in supine and upright position. Despite a significant autoregulatory deficit distally to BVAD, the posterior cerebral blood supply seemed to be sufficiently maintained as long as systemic blood pressure changes were within normal limits. Posterior cerebral flow velocities, however, were significantly diminished when PT detected a systemic hypotension in upright position. This study proves the feasibility to combine PT and TCD monitoring of the PCA in patients with BVAD. In vertebrobasilar artery disease, the examination of spontaneous and tilt-induced autoregulatory responses could support the evaluation of a risk for hemodynamic ischemia.
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PMID:Bilateral vertebral artery disease: transcranial Doppler assessment of the hemodynamic vulnerability to changes in posture. 1704 68

Posterior fossa ischemia is not a very frequent situation. It is responsible for about 25% of all ischemic strokes, and the vast majority of the cases are related to atherosclerotic stenosis of the vertebral and/or basilar arteries. Acute ischemia can also occur in the setting of vertebral artery dissection, traumatic or spontaneous. Recently, blunt trauma has been increasingly recognized as a cause for craniocervical artery injury. The management options for both traumatic and atherosclerotic lesions of the posterior fossa are still under debate. We present a case of a delayed onset of hemodynamic ischemic symptoms due to bilateral vertebral artery occlusion probably related to remote trauma to the head and neck in a 55-year-old-man treated successfully with extracranial to intracranial bypass.
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PMID:Symptomatic non-atherosclerotic bilateral extracranial vertebral artery occlusion treated with extracranial to intracranial bypass: case report. 1711 15

Posterior circulation infarction is uncommon in children. Vertebral artery dissection is an unusual cause of posterior circulation infarction in children. We report on a 12-year-old boy with spontaneous left-extracranial vertebral artery dissection associated with isolated ipsilateral superior cerebellar artery territory infarction, diagnosed clinically and by brain computed tomography, magnetic resonance imaging, and magnetic resonance angiography. Cerebral angiography demonstrated a flame-like occlusion of the left vertebral artery at level C(2)-C(3), and indicated that artery-to-artery embolus may be a mechanism of superior cerebellar artery territory infarction. We emphasize that vertebral artery dissection should be considered in a child with acute signs of posterior circulation ischemia.
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PMID:Cerebellar infarction in the territory of the superior cerebellar artery in children. 1802 27

Posterior reversible encephalopathy syndrome (PRES) is a neurotoxic state accompanied by a unique brain imaging pattern typically associated with a number of complex clinical conditions including: preeclampsia/eclampsia, allogeneic bone marrow transplantation, solid organ transplantation, autoimmune diseases and high dose cancer chemotherapy. The mechanism behind the developing vasogenic edema and CT or MR imaging appearance of PRES is not known. Two theories have historically been proposed: 1) Severe hypertension leads to failed auto-regulation, subsequent hyperperfusion, with endothelial injury/vasogenic edema and; 2) vasoconstriction and hypoperfusion leads to brain ischemia and subsequent vasogenic edema. The strengths/weaknesses of these hypotheses are reviewed in a translational fashion including supporting evidence and current available imaging/clinical data related to the conditions that develop PRES. While the hypertension/hyperperfusion theory has been most popular, the conditions associated with PRES have a similar immune challenge present and develop a similar state of T-cell/endothelial cell activation that may be the basis of leukocyte trafficking and systemic/cerebral vasoconstriction. These systemic features along with current vascular and perfusion imaging features in PRES appear to render strong support for the older theory of vasoconstriction coupled with hypoperfusion as the mechanism.
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PMID:Posterior reversible encephalopathy syndrome, part 2: controversies surrounding pathophysiology of vasogenic edema. 1840 60

Posterior reversible encephalopathy (PRES) represents an uncommon entity related to multiple pathologies, the most common of which is hypertensive crisis. PRES is classically characterized as symmetrical parieto-occipital edema, but may affect other areas of the brain. Diffusion-weighted magnetic resonance imaging (DWI) is important for differentiating between vasogenic and cytotoxic edema. We present here the case of a 43-year-old woman, known to suffer from arterial hypertension and severe renal failure, who developed PRES with restricted apparent diffusion coefficients (ADC) in various cerebral areas, suggesting irreversible tissue damage. Nevertheless, follow-up cranial MRI revealed complete remission, indicating that restricted diffusion does not always lead to cell death in this pathology. The underlying pathophysiological mechanism is not well understood. Such reversibility of diffusion anomalies has already been reported with transient ischemia, vasospasm after subarachnoid hemorrhage and epilepsy but, to our knowledge, never before in PRES.
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PMID:Posterior reversible encephalopathy syndrome: a case of unusual diffusion-weighted MR images. 1883 39

Posterior elbow dislocations are the most common type of elbow dislocation and are usually caused by a fall on an outstretched hand. Although the incidence of elbow dislocation complications is rare, the emergency physician is responsible for evaluation and identification of concomitant neurovascular injuries. Failure to identify neurovascular compromise after elbow dislocation or reduction can potentially lead to severe morbidity with limb ischemia, neurologic changes, compartment syndrome, and potential loss of limb. Cyanosis, pallor, pulselessness, and marked pain should suggest vascular injury or compartment syndrome, both requiring immediate intervention. Patients in whom it is not clear if there is vascular injury should undergo further imaging with angiography, considered the gold standard for evaluation of arterial damage. It is important for the emergency physician to maintain a high level of suspicion and evaluate for neurovascular compromise on every patient with elbow dislocation despite the low overall incidence of severe injury.
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PMID:Orthopedic pitfalls in the ED: neurovascular injury associated with posterior elbow dislocations. 2088 16

We report the case of a young patient with 36 weeks pregnancy, and an acute respiratory infection with severe bronchospasm, who developed an occipital headache and neck pain on the third day of inadvertent dural puncture during placement of combined epidural spinal anaesthesia for caesarian section. It was diagnosed as post-dural puncture headache until generalised tonic clonic seizures occurred the next day raising the suspicion of postpartum eclampsia or meningitis. Posterior reversible encephalopathy syndrome was diagnosed on MRI of the brain which showed features of reversible ischemia in the posterior region of the brain. With anticonvulsant therapy and antibiotics there was complete resolution of neurological symptoms. We highlight the importance of high index of suspicion of this reversible encephalopathy in obstetric cases with intentional or inadvertent dural puncture, with headache similar to post-dural punctural headache, and the essential role of neuroradiology in confirmation of the diagnosis, as placement of an epidural blood patch would be highly detrimental in these cases.
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PMID:Post-dural puncture posterior reversible encephalopathy syndrome. 2127 84

Moyamoya disease is a progressive steno-occlusive disease of bilateral carotid forks with the formation of fine collateral vascular network and is an angiographic diagnosis. We analyzed case records of 11 patients with "adult-onset moyamoya disease." Six patients presented with intracranial hemorrhage (intracerebral and/or intraventricular) and 5 with focal ischemia. Angiography revealed bilateral Internal carotid artery involvement in 8 patients and unilateral involvement in 3. Posterior cerebral artery involvement was seen in 3 patients. Saccular aneurysm involving posterior circulation was seen in only 1 patient. Although rare, adult-onset moyamoya disease should be considered as one of the causes for intracerebral and intraventricular hemorrhage in adults.
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PMID:Adult onset moyamoya disease: institutional experience. 2201 60

Posterior reversible encephalopathy syndrome (PRES) is a clinical syndrome of encephalopathy, headache, visual disturbance, and seizures. In most cases, symptoms present acutely or subacutely in the setting of accelerated hypertension, eclampsia, autoimmune disease, immunosuppressive treatment, or cancer chemotherapy. One essential feature of PRES is the presence of reversible cerebral vasogenic edema that has a predominantly posterior distribution on brain imaging. Atypical imaging features are commonly described, including involvement of the anterior brain or brainstem and the coexistence of ischemia or hemorrhage. In most cases, both clinical and radiological findings are reversible, although permanent imaging abnormalities and residual neurological sequelae can be seen in a minority of patients. The syndrome is thought to be caused by a breakdown of the blood-brain barrier and an extravasation of the intravascular fluid. Treatment of hypertension and seizures, and withdrawal of causative agents are the mainstays of therapy in PRES.
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PMID:Posterior reversible encephalopathy syndrome: clinicoradiological spectrum and therapeutic strategies. 2240 96

Stent-grafting of thoracic aortic diseases has developed as an alternative therapeutic modality in thoracic aneurysm management. Postprocedural complications include mortality, endoleaks, paraplegia and stroke. Other complications that may arise in cases of overstenting the origin of the left subclavian arther include left upper limb ischemia, subclavian steal syndrome and stroke. Posterior circulation strokes due to vertebral artery insufficiency have been reported in the past. In the present case, a fatal stroke caused by a cerebellar infarct culminating in the death of a patient with a leaking thoracic aortic aneurysm is reported. Medical personnel as well as patients should be aware of this possible complication. Vigilance in assessing the contralateral cerebral circulation before the procedure is a prerequisite in less acute circumstances.
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PMID:Fatal cerebellar stroke following emergency endovascular stent grafting of a leaking thoracic aortic aneurysm: A case report. 2247 74


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