出典(authority):フリー百科事典『ウィキペディア(Wikipedia)』「2012/10/10 23:05:41」(JST)
Cerebral infarct | |
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Classification and external resources | |
CT scan slice of the brain showing a right-hemispheric cerebral infarct (left side of image). |
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ICD-10 | I63 |
ICD-9 | 434.01, 434.11, 434.91 |
eMedicine | neuro/ |
MeSH | D002544 |
A cerebral infarction is an ischemic stroke resulting from a disturbance in the blood vessels supplying blood to the brain. It can be atherothrombotic or embolic.[1] Stroke caused by cerebral infarction should be distinguished from two other kinds of stroke: cerebral hemorrhage and subarachnoid hemorrhage. A cerebral infarction occurs when a blood vessel that supplies a part of the brain becomes blocked or leakage occurs outside the vessel walls. This loss of blood supply results in the death of that area of tissue. Cerebral infarctions vary in their severity with one third of the cases resulting in death.
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There are various classification systems for a cerebral infarction.
Symptoms of cerebral infarction are determined by topographical localisation of cerebral lesion. If the infarct is located in primary motor cortex- contralateral hemiparesis is said to occur. With brainstem localization, brainstem syndromes are typical: Wallenberg's syndrome, Weber's syndrome, Millard-Gubler syndrome, Benedikt syndrome or others. Infarctions will result in weakness and loss of sensation on the opposite side of the body. Physical examination of the head area will reveal abnormal pupil dilation, light reaction and lack of eye movement on opposite side. If the infarction occurs on the left side brain, speech will be slurred. Reflexes may be aggravated as well.
In thrombotic cerebral infarction a thrombus usually forms around atherosclerotic plaques. An embolic stroke refers to the blockage of an artery by an embolus, a traveling particle or debris in the arterial bloodstream originating elsewhere. An embolus is most frequently a thrombus, but it can also be a number of other substances including fat (e.g. from bone marrow in a broken bone), air, cancer cells or clumps of bacteria (usually from infectious endocarditis). The embolus may be of cardiac origin or from atherosclerotic plaque of another (or the same) large artery.
Risk factors for cerebral infarction are generally the same as for atherosclerosis: diabetes, tobacco smoking, hypercholesterolemia, hyperlipoproteinemia, high blood pressure, obesity.
Computed tomography (CT) and MRI scanning will show damaged area in the brain, showing that the symptoms were not caused by a tumor, subdural hematoma or other brain disorder. The blockage will also appear on the angiogram.
In last decade, similar to myocardial infarction treatment, thrombolytic drugs were introduced in the therapy of cerebral infarction. The use of intravenous rtPA therapy can be advocated in patients who arrive to stroke unit and can be fully evaluated within 3 h of the onset.
If cerebral infarction is caused by a thrombus occluding blood flow to an artery supplying the brain, definitive therapy is aimed at removing the blockage by breaking the clot down (thrombolysis), or by removing it mechanically (thrombectomy). The more rapidly blood flow is restored to the brain, the fewer brain cells die.[5] In increasing numbers of primary stroke centers, pharmacologic thrombolysis with the drug tissue plasminogen activator (tPA), is used to dissolve the clot and unblock the artery. Another intervention for acute cerebral ischaemia is removal of the offending thrombus directly. This is accomplished by inserting a catheter into the femoral artery, directing it into the cerebral circulation, and deploying a corkscrew-like device to ensnare the clot, which is then withdrawn from the body. Mechanical embolectomy devices have been demonstrated effective at restoring blood flow in patients who were unable to receive thrombolytic drugs or for whom the drugs were ineffective,[6][7][8][9] though no differences have been found between newer and older versions of the devices.[10] The devices have only been tested on patients treated with mechanical clot embolectomy within eight hours of the onset of symptoms.
Angioplasty and stenting have begun to be looked at as possible viable options in treatment of acute cerebral ischaemia. In a systematic review of six uncontrolled, single-center trials, involving a total of 300 patients, of intra-cranial stenting in symptomatic intracranial arterial stenosis, the rate of technical success (reduction to stenosis of <50%) ranged from 90-98%, and the rate of major peri-procedural complications ranged from 4-10%. The rates of restenosis and/or stroke following the treatment were also favorable.[11] This data suggests that a large, randomized controlled trial is needed to more completely evaluate the possible therapeutic advantage of this treatment.
If studies show carotid stenosis, and the patient has residual function in the affected side, carotid endarterectomy (surgical removal of the stenosis) may decrease the risk of recurrence if performed rapidly after cerebral infarction. Carotid endarterectomy is also indicated to decrease the risk of cerebral infarction for symptomatic carotid stenosis (>70 to 80 reduction in diameter). [12]
In tissue losses that are not immediately fatal, the best course of action is to make every effort to restore impairments through physical therapy, speech therapy and exercise.
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リンク元 | 「脳梗塞」「cerebral infarct」「大脳梗塞」 |
関連記事 | 「cerebral」 |
アテローム血栓性脳梗塞 | ラクナ梗塞 | 心原性脳塞栓 | |
発症機序 | 血栓性 塞栓性 血行力学性 |
血栓症 | 塞栓性 |
好発年齢 | 高齢者 | 高齢者 | 若年者もあり |
発症時刻 | 起床時 | 覚醒時 | 日中活動時 |
発症様式 | 緩徐進行 | 比較的緩徐進行 | 突発的 |
意識障害 | 軽度 | なし | しばしば高度 |
大脳皮質症状 | 時にあり | なし | あり |
基礎疾患 | 高血圧 糖尿病 高脂血症 |
高血圧 | 心疾患 |
治療 YN.J-81 | |||
時期 | ラクナ梗塞 | アテローム血栓性脳梗塞 | 心原性塞栓症 |
超急性期(~3時間) | 血栓溶解療法(t-PA静注) | ||
超急性期+急性期 | 脳保護薬(エダラボン) | ||
急性期(~2週間) | 抗血小板療法(アスピリン) | ||
抗血小板療法(オザグレル) | 抗凝固療法(ヘパリン、ワルファリン) | ||
選択的トロンビン阻害薬(アルガトロバン) | |||
抗浮腫療法(グリセロール) |
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