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Query: UMLS:C0038454 (stroke)
 147,016 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Fibromuscular dysplasia of the arteries (FMD) is a segmental angiopathy which may produce obstruction of the carotid, cerebral, renal, mesenteric, coronary or iliac arteries. Except for lesions related to arterial hypertension, retinal manifestations have not yet been reported. This paper describes the case of a 10-year-old boy with progressive deafness, a history of an unexplained stroke and progressive occlusions of the retinal arterioles in the fundus periphery. This resulted in retinal neovascularization and recurrent retinal and vitreous hemorrhages. Despite repeated photo- and cryocoagulation the eyes progressed to a tractional retinal detachment which was successfully treated by vitrectomy and scleral buckling. The diagnosis of FMD was made on the basis of a histopathological examination of a temporal artery biopsy. The child also presented an asymptomatic but severe aneurysmal dilatation of the aorta and CT scan and MRI showed dilated cerebral arteries. The father of our patient had died at the age of 27 years either from myocardial infarction or rupture of a dissecting aortic aneurysm. He was highly myopic and had lost one eye from retinal detachment. The younger brother of our patient also presents aneurysmal dilatation of the aorta and tortuous cerebral vessels. Ocular examination is still normal. The findings in this family are compatible with an autosomal dominant inheritance with variable expression.
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PMID:Retinal manifestations in fibromuscular dysplasia. 182 Dec 2

We evaluated the accuracy of administrative data for identifying complications and comorbidities of diabetes using International Classification of Diseases, 9th edition, Clinical Modification and Current Procedural Terminology codes. The records of 471 randomly selected diabetic patients were reviewed for complications from January 1, 1993 to December 31, 1995; chart data served to validate automated data. The complications with the highest sensitivity determined by a diagnosis in the medical records identified within +/-60 days of the database date were myocardial infarction (95.2%); amputation (94.4%); ischemic heart disease (90.3%); stroke (91.2%); osteomyelitis (79.2%); and retinal detachment, vitreous hemorrhage, and vitrectomy (73.5%). With the exception of amputation (82.9%), positive predictive value was low when based on a diagnosis identified within +/-60 days of the database date but increased with relaxation of the time constraints to include confirmation of the condition at any time during 1993-1995: ulcers (88.5%); amputation (85.4%); and retinal detachment, vitreous hemorrhage and vitrectomy (79.8%). Automated data are useful for ascertaining potential cases of some diabetic complications but require confirmatory evidence when they are to be used for research purposes.
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PMID:The use of automated data to identify complications and comorbidities of diabetes: a validation study. 1021 Feb 37

Recent publications have suggested that intra-ocular pressure (IOP) may be an indirect assessment of intra-cranial pressure (ICP). Both IOP and ICP have similar physiologic pressure ranges and similar responses to changes in intra-abdominal, intra-thoracic and aortic pressure. Previous studies have demonstrated the relationships between retinal arterial pressure and aortic pressure, intra-ocular pressure and retinal venous pressure, intra-cranial pressure and retinal venous pressure. Power athletes routinely utilize the Valsalva maneuver during weightlifting. In fact there are reports of stroke, cerebral hemorrhage, subarachnoid hemorrhage, conjunctival, foveal and retinal hemorrhage, retinal detachment, hiatal hernia and pneumothorax associated with weightlifting. These events are thought to occur secondary to the extreme pressure elevations that occur in the intra-abdominal, intra-thoracic, intra-cranial, intra-ocular and vascular compartments. To date no human studies have examined the IOP changes that may occur with heavy resistance exercise. Therefore, we recruited power athletes (n = 11), who had participated in prior studies, from the local metropolitan area. The athletes had blood pressure status, drug screening and medical histories performed during previous investigations. Intra-ocular pressure was measured by noncontact tonometry at rest and during maximal isometric contraction. All subjects resting IOP were within normal ranges (mean 13 +/- 2.8 mmHg). Intra-ocular pressures were significantly (p < 0.0001) elevated in each subject during maximal contraction (mean 28 +/- 9.3 mmHg). One subject's IOP reached 46 mmHg during maximal contraction. Linear regression analysis demonstrated a significant linear relationship (r = 0.62, p < 0.0001) in the net change of IOP from rest to maximal contraction for each subject. This study demonstrates that IOP elevates to pathophysiologic levels during resistance exercise. The findings of conjunctival hemorrhages in two subjects further supports IOP being reflective of retinal venous pressure. The enormous pressures generated by power athletes during weightlifting leads to elevations in ICP which obstruct venous outflow leading to hemorrhage and elevations in IOP. The question remains as to whether these intermittent bursts of elevated IOP can lead to long-term pathological sequelae.
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PMID:Intra-ocular pressure changes during maximal isometric contraction: does this reflect intra-cranial pressure or retinal venous pressure? 1031 30

Cerebral blood flow velocity (CBFV) has been shown to significantly increase during dynamic exercise (running) secondary to increases in cardiac output. Static exercise (weight-lifting) induces supraphysiological arterial pressures up to 450/380 mmHg, and thus may alter CBFV. Catastrophic brain injuries such as stroke, cerebral hemorrhage, subarachnoid hemorrhage, retinal hemorrhage and retinal detachment have been associated with weight-lifting. A recent study has shown that intra-ocular pressure (IOP), which is an indirect measure of intracranial pressure, elevates to pathophysiologic levels during weight-lifting. Recent CBFV studies instituting Valsalva have demonstrated decreases in CBFV from 21%-52%. To date, no studies have examined CBFV during maximal weight-lifting to elucidate the cerebrovascular responses to extreme pressure alterations. We recruited nine elite power athletes, including a multi-world record holder in powerlifting, for a transcranial Doppler study of middle cerebral artery blood flow velocity at rest and during maximal weight-lifting. All subjects' resting blood flow velocities were within normal ranges (mean 64.4 +/- 9.5 cm sec2). Blood flow velocities were significantly (p < 0.0001) decreased in all subjects during maximal lifting (mean 48.4 +/- 10.1 cm sec2). Linear regression analysis demonstrated a significant inverse linear relationship in the net change of blood velocities from rest to maximal lift for each subject (r = 0.8585, p < 0.001). This study demonstrates that blood flow velocities are significantly decreased during heavy resistance training. The drop in CBFV during weight-lifting was significantly less than previous Valsalva studies, which likely reveals the cardiovascular, baroreflex, and cerebrovascular system adaptations occurring in these elite power athletes.
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PMID:Middle cerebral artery blood flow velocity in elite power athletes during maximal weight-lifting. 1087 79

Vitreous haemorrhage can be caused by a disruption of normal retinal vessels, bleeding from diseased retinal vessels, bleeding from abnormal new vessels or extension of haemorrhage through the retina from other sources. In the elderly, vitreous haemorrhage usually occurs spontaneously and only occurs occasionally as a result of trauma. Appropriate management of vitreous haemorrhage is dependent on the most likely cause in a particular patient. As always, an accurate medical history with a careful clinical examination, static and dynamic ultrasonography performed by an experienced examiner, results of other laboratory tests and an understanding of the common causes of vitreous haemorrhage in each age group is essential to come to a 'best guess' diagnosis as to the cause of the vitreous haemorrhage and thus guide the physician toward the appropriate management. Immediate surgical removal of blood if indicated, as well as improving the vision gives the added benefit of allowing a full examination of the underlying retina. For those in whom surgical removal of blood is not recommended, a careful and frequent follow-up with serial B-scan ultrasound allows the 'best guess' diagnosis to be confirmed at each visit, until such time as the vitreous haemorrhage resolves sufficiently to allow a full and proper examination of the retina. Where there is a confirmed retinal tear, retinal detachment or other fundal pathology these are treated appropriately with laser or surgery (vitrectomy). Preventative measures are dependent on the underlying cause of vitreous haemorrhage. Some of the underlying causes such as posterior vitreous detachment cannot be prevented. In others, such as retinal vein occlusion, measures may need to be taken so as to reduce the risk of a similar event in the same or fellow eye and to reduce the risk of potentially life-threatening associated systemic conditions such as a stroke or myocardial infarction.
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PMID:Vitreous haemorrhage in elderly patients: management and prevention. 1283 Dec 90

Evidence is presented which supports the conclusion that the hormetic dose-response model is the most common and fundamental in the biological and biomedical sciences, being highly generalizable across biological model, endpoint measured and chemical class and physical agent. The paper provides a broad spectrum of applications of the hormesis concept for clinical medicine including anxiety, seizure, memory, stroke, cancer chemotherapy, dermatological processes such as hair growth, osteoporosis, ocular diseases, including retinal detachment, statin effects on cardiovascular function and tumour development, benign prostate enlargement, male sexual behaviours/dysfunctions, and prion diseases.
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PMID:Hormesis and medicine. 1866 93

The volume of cells that a length of capillary supplies with O(2) is called a Krogh cylinder. This geometric 'tissue unit' was named after the Danish zoophysiologist and Nobel laureate August Krogh who made important discoveries in the fields of external and internal respiration in the first half of the last century. Krogh's ideas concerning tissue O(2) distribution can be extrapolated to retinal oxygenation by larger vessels (including arterioles, arteries and even veins) and by vessel groups within higher-order 'microvascular units' (including the choroid). During retinal development, for example, the difference in pO(2) levels within arteries and capillaries determines Krogh cylinders of different radius and establishes the periarterial capillary-free zone of His. The O(2) supply to the venous end of a tissue unit may be compromised during periods of reduced perfusion, increased O(2) consumption or hypoxaemia, resulting in an 'anoxic corner' of the Krogh cylinder. A funnel of hypometabolic (and therefore hypoxia-tolerant) cells will likely intervene between the necrotic cells and unaffected cells located closer to the O(2) source. Macular perivenular whitening heralds anoxic corners and/or hypoxic funnels owing to hypoperfusion within second-order microvascular units. In eyes with extensive retinal capillary closure from diabetes, Krogh cylinders surround the medium-sized arteries and veins that form arteriovenous shunts while traversing the midperipheral retina. These isolated tissue units incorporate an outer sheath of hypoxic cells within which vascular endothelial growth factor is upregulated. This 'angiogenic sheath' expands following retinal detachment; it corresponds to the hypoxia-tolerant funnel within capillary-based tissue units and to the cerebral penumbra after stroke.
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PMID:Krogh cylinders in retinal development, panretinal hypoperfusion and diabetic retinopathy. 2006 21

Management of the pregnant woman with a neuro-ophthalmic disorder may be challenging. Physiologic changes in pregnancy make vascular conditions more frequent, including retinal artery occlusion, spontaneous orbital hemorrhage, and pituitary apoplexy. Papilledema may signal cerebral venous sinus thrombosis or idiopathic intracranial hypertension. Manifestations of severe preeclampsia and eclampsia include choroidal infarction, serous retinal detachment, and disorders of higher cortical function, such as alexia, simultanagnosia, and cerebral blindness. Cranial neuropathies have also been reported. Transient Horner syndrome, intracranial hypotension with comitant esotropia may occur in the postpartum period. Treatment of the neuro-ophthalmic complications of pregnancy requires an understanding of the risks of medications. Taking optimal care of the mother will usually result in the best care for her baby.
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PMID:Neuro-ophthalmology and pregnancy: what does a neuro-ophthalmologist need to know? 2208 2

Sudden loss of vision without redness nor eye pain may come from numerous causes of varying severity. It presents a major source of anxiety for the patient who will seek for urgent consultation. The diagnostic approach is based on history and eye examination, eventually completed by a neurological examination. The purpose of this article is to provide general practitioners simple clues allowing them to quickly orientate the diagnosis. Following simple guidelines, they will be able to treat the condition correctly or refer to an adequate specialist when needed. True emergencies are retinal detachment, central retinal artery occlusion, intracranial hypertension, Horton giant cells arteritis, transient ischemic attack, stroke, pituitary apoplexy and cortical visual loss.
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PMID:[Diagnosis of a sudden loss of vision (without redness nor eye pain)]. 2567 30

Intracranial silicone oil is a rare complication of intraocular endotamponade with silicone oil. We describe a case of intraventricular silicone oil fortuitously observed 38 months after an intraocular tamponade for a complicated retinal detachment in an 82 year-old woman admitted in the Department of Neurology for a stroke. We confirm the migration of silicone oil along the optic nerve. We discuss this rare entity with a review of the few other cases reported in the medical literature. Intraventricular migration of silicone oil after intraocular endotamponade is usually asymptomatic but have to be known of the neurologists and the radiologists because of its differential diagnosis that are intraventricular hemorrhage and tumor.
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PMID:Intraventricular Silicone Oil: A Case Report. 2673 37


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