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By definition, TIAs are transient, self-resolving, and do not cause permanent impairment. However, they are associated with an increased risk of subsequent ischemic strokes, which can be permanently disabling. Therefore, management centers around the prevention of future ischemic strokes and addressing any modifiable risk factors. The optimal regimen depends on the underlying cause of the TIA.
A number of specific recommendations have been made for women including taking aspirin after the 11th week of pregnancy if there is a history of previous chronic high blood pressure and taking blood pressure medications during pregnancy if the blood pressure is greater than 150 mmHg systolic or greater than 100 mmHg diastolic. In those who have previously had preeclampsia other risk factors should be treated more aggressively.
High blood pressure accounts for 35–50% of stroke risk. Blood pressure reduction of 10 mmHg systolic or 5 mmHg diastolic reduces the risk of stroke by ~40%. Lowering blood pressure has been conclusively shown to prevent both ischemic and hemorrhagic strokes. It is equally important in secondary prevention. Even patients older than 80 years and those with isolated systolic hypertension benefit from antihypertensive therapy. The available evidence does not show large differences in stroke prevention between antihypertensive drugs —therefore, other factors such as protection against other forms of cardiovascular disease and cost should be considered. The routine use of beta-blockers following a stroke or TIA has not been shown to result in benefits.
An antiplatelet, such as aspirin, is started for secondary prevention of stroke after most TIAs. An exception is TIAs due to blood clots originating from the heart, in which case anticoagulants are generally recommended. After TIA or minor stroke, aspirin therapy has been shown to reduce the short-term risk of recurrent stroke by 60-70%, and the long-term risk of stroke by 13%.
The typical therapy may include aspirin alone, a combination of aspirin plus extended-release dipyridamole, or clopidogrel alone. Clopidogrel and aspirin have similar efficacies and side effect profiles. Clopidogrel is more expensive and has a slightly decreased risk of GI bleed. There is some evidence that giving both aspirin and clopidogrel within 24 hours of a TIA or minor stroke is more effective than aspirin alone. Another antiplatelet, ticlopidine, is rarely used due to increased side effects.
Alteplase (tpa) is an effective medication for acute ischemic stroke. When given within 3 hours, treatment with tpa significantly improves the probability of a favourable outcome versus treatment with placebo.
The outcome of brain ischemia is influenced by the quality of subsequent supportive care. Systemic blood pressure (or slightly above) should be maintained so that cerebral blood flow is restored. Also, hypoxaemia and hypercapnia should be avoided. Seizures can induce more damage; accordingly, anticonvulsants should be prescribed and should a seizure occur, aggressive treatment should be undertaken. Hyperglycaemia should also be avoided during brain ischemia.
When someone presents with an ischemic event, treatment of the underlying cause is critical for prevention of further episodes.
Anticoagulation with warfarin or heparin may be used if the patient has atrial fibrillation.
Operative procedures such as carotid endarterectomy and carotid stenting may be performed if the patient has a significant amount of plaque in the carotid arteries associated with the local ischemic events.
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. 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, though no differences have been found between newer and older versions of the devices. 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. 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).
In tissue losses that are not immediately fatal, the best course of action is to make every effort to restore impairments through physical therapy, cognitive therapy, occupational therapy, speech therapy and exercise.
Prognostics factors:
Lower Glasgow coma scale score, higher pulse rate, higher respiratory rate and lower arterial oxygen saturation level is prognostic features of in-hospital mortality rate in acute ischemic stroke.
Preventive measures that can be taken to avoid sustaining a silent stroke are the same as for stroke. Smoking cessation is the most immediate step that can be taken, with the effective management of hypertension the major medically treatable factor.
Treatment for cerebrovascular disease may include medication, lifestyle changes and/or surgery, depending on the cause.
Examples of medications are:
- antiplatelets (aspirin, clopidogrel)
- blood thinners (heparin, warfarin)
- antihypertensives (ACE inhibitors, beta blockers)
- anti-diabetic medications.
Surgical procedures include:
- endovascular surgery and vascular surgery (for future stroke prevention).
Transfusion therapy lowers the risk for a new silent stroke in children who have both abnormal cerebral artery blood flow velocity, as detected by transcranial Doppler, and previous silent infarct, even when the initial MRI showed no abnormality. A finding of elevated TCD ultrasonographic velocity warrants MRI of the brain, as those with both abnormalities who are not provided transfusion therapy are at higher risk for developing a new silent infarct or stroke than are those whose initial MRI showed no abnormality.
Major risk factors for cerebral infarction are generally the same as for atherosclerosis: high blood pressure, Diabetes mellitus, tobacco smoking, obesity, and dyslipidemia. The American Heart Association/American Stroke Association (AHA/ASA) recommends controlling these risk factors in order to prevent stroke. The AHA/ASA guidelines also provide information on how to prevent stroke if someone has more specific concerns, such as Sickle-cell disease or pregnancy. It is also possible to calculate the risk of stroke in the next decade based on information gathered through the Framingham Heart Study.
Typically, tissue plasminogen activator may be administered within three to four-and-a-half hours of stroke onset if the patient is without contraindications (i.e. a bleeding diathesis such as recent major surgery or cancer with brain metastases). High dose aspirin can be given within 48 hours. For long term prevention of recurrence, medical regimens are typically aimed towards correcting the underlying risk factors for lacunar infarcts such as hypertension, diabetes mellitus and cigarette smoking. Anticoagulants such as heparin and warfarin have shown no benefit over aspirin with regards to five year survival.
Patients who suffer lacunar strokes have a greater chance of surviving beyond thirty days (96%) than those with other types of stroke (85%), and better survival beyond a year (87% versus 65-70%). Between 70% and 80% are functionally independent at 1 year, compared with fewer than 50% otherwise.
Occupational Therapy and Physical Therapy interventions are used in the rehabilitation of lacunar stroke. A physiotherapy program will improve joint range of motion of the paretic limb using passive range of motion exercises. When increases in activity are tolerated, and stability improvements are made, patients will progress from rolling to side-lying, to standing (with progressions to prone, quadruped, bridging, long-sitting and kneeling for example) and learn to transfer safely (from their bed to a chair or from a wheel chair to a car for example). Assistance and ambulation aids are used as required as the patient begins walking and lessened as function increases. Furthermore, splints and braces can be used to support limbs and joints to prevent complications such as contractures and spasticity. The rehabilitation healthcare team should also educate the patient and their family on common stroke symptoms and how to manage an onset of stroke. Continuing follow-up with a physician is essential so that the physician may monitor medication dosage and risk factors.
It is estimated that lacunar infarcts account for 25% of all ischemic strokes, with an annual incidence of approximately 15 per 100,000 people. They may be more frequent in men and in people of African, Mexican, and Hong Kong Chinese descent.
70% of patients with carotid arterial dissection are between the ages of 35 and 50, with a mean age of 47 years.
The goal of treatment is to prevent the development or continuation of neurologic deficits. Treatments include observation, anticoagulation, stent implantation and carotid artery ligation.
Intracerebral hemorrhages is a severe condition requiring prompt medical attention. Treatment goals include lifesaving interventions, supportive measures, and control of symptoms. Treatment depends on the location, extent, and cause of the bleeding. Often, treatment can reverse the damage that has been done.
A craniotomy is sometimes done to remove blood, abnormal blood vessels, or a tumor. Medications may be used to reduce swelling, prevent seizures, lower blood pressure, and control pain.
Nontraumatic intraparenchymal hemorrhage most commonly results from hypertensive damage to blood vessel walls e.g.:
- hypertension
- eclampsia
- drug abuse,
but it also may be due to autoregulatory dysfunction with excessive cerebral blood flow e.g.:
- reperfusion injury
- hemorrhagic transformation
- cold exposure
- rupture of an aneurysm or arteriovenous malformation (AVM)
- arteriopathy (e.g. cerebral amyloid angiopathy, moyamoya)
- altered hemostasis (e.g. thrombolysis, anticoagulation, bleeding diathesis)
- hemorrhagic necrosis (e.g. tumor, infection)
- venous outflow obstruction (e.g. cerebral venous sinus thrombosis).
Nonpenetrating and penetrating cranial trauma can also be common causes of intracerebral hemorrhage.
Cerebral hypoxia is a form of hypoxia (reduced supply of oxygen), specifically involving the brain; when the brain is completely deprived of oxygen, it is called "cerebral anoxia". There are four categories of cerebral hypoxia; they are, in order of severity: diffuse cerebral hypoxia (DCH), focal cerebral ischemia, cerebral infarction, and global cerebral ischemia. Prolonged hypoxia induces neuronal cell death via apoptosis, resulting in a hypoxic brain injury.
Cases of total oxygen deprivation are termed "anoxia", which can be hypoxic in origin (reduced oxygen availability) or ischemic in origin (oxygen deprivation due to a disruption in blood flow). Brain injury as a result of oxygen deprivation either due to hypoxic or anoxic mechanisms are generally termed hypoxic/anoxic injuries (HAI). Hypoxic ischemic encephalopathy (HIE) is a condition that occurs when the entire brain is deprived of an adequate oxygen supply, but the deprivation is not total. While HIE is associated in most cases with oxygen deprivation in the neonate due to birth asphyxia, it can occur in all age groups, and is often a complication of cardiac arrest.
Splenic infarction can be induced for the treatment of such conditions as portal hypertension or splenic injury. It can also be used prior to splenectomy for the prevention of blood loss.
For newborn infants starved of oxygen during birth there is now evidence that hypothermia therapy for neonatal encephalopathy applied within 6 hours of cerebral hypoxia effectively improves survival and neurological outcome. In adults, however, the evidence is less convincing and the first goal of treatment is to restore oxygen to the brain. The method of restoration depends on the cause of the hypoxia. For mild-to-moderate cases of hypoxia, removal of the cause of hypoxia may be sufficient. Inhaled oxygen may also be provided. In severe cases treatment may also involve life support and damage control measures.
A deep coma will interfere with body's breathing reflexes even after the initial cause of hypoxia has been dealt with; mechanical ventilation may be required. Additionally, severe cerebral hypoxia causes an elevated heart rate, and in extreme cases the heart may tire and stop pumping. CPR, defibrilation, epinephrine, and atropine may all be tried in an effort to get the heart to resume pumping. Severe cerebral hypoxia can also cause seizures, which put the patient at risk of self-injury, and various anti-convulsant drugs may need to be administered before treatment.
There has long been a debate over whether newborn infants with cerebral hypoxia should be resuscitated with 100% oxygen or normal air. It has been demonstrated that high concentrations of oxygen lead to generation of oxygen free radicals, which have a role in reperfusion injury after asphyxia. Research by Ola Didrik Saugstad and others led to new international guidelines on newborn resuscitation in 2010, recommending the use of normal air instead of 100% oxygen.
Brain damage can occur both during and after oxygen deprivation. During oxygen deprivation, cells die due to an increasing acidity in the brain tissue (acidosis). Additionally, during the period of oxygen deprivation, materials that can easily create free radicals build up. When oxygen enters the tissue these materials interact with oxygen to create high levels of oxidants. Oxidants interfere with the normal brain chemistry and cause further damage (this is known as "reperfusion injury").
Techniques for preventing damage to brain cells are an area of ongoing research. Hypothermia therapy for neonatal encephalopathy is the only evidence-supported therapy, but antioxidant drugs, control of blood glucose levels, and hemodilution (thinning of the blood) coupled with drug-induced hypertension are some treatment techniques currently under investigation. Hyperbaric oxygen therapy is being evaluated with the reduction in total and myocardial creatine phosphokinase levels showing a possible reduction in the overall systemic inflammatory process.
In severe cases it is extremely important to act quickly. Brain cells are very sensitive to reduced oxygen levels. Once deprived of oxygen they will begin to die off within five minutes.
Various studies have investigated the use of anticoagulation to suppress blood clot formation in cerebral venous sinus thrombosis. Before these trials had been conducted, there had been a concern that small areas of hemorrhage in the brain would bleed further as a result of treatment; the studies showed that this concern was unfounded. Clinical practice guidelines now recommend heparin or low molecular weight heparin in the initial treatment, followed by warfarin, provided there are no other bleeding risks that would make these treatments unsuitable. Some experts discourage the use of anticoagulation if there is extensive hemorrhage; in that case, they recommend repeating the imaging after 7–10 days. If the hemorrhage has decreased in size, anticoagulants are started, while no anticoagulants are given if there is no reduction.
The duration of warfarin treatment depends on the circumstances and underlying causes of the condition. If the thrombosis developed under temporary circumstances (e.g. pregnancy), three months are regarded as sufficient. If the condition was unprovoked but there are no clear causes or a "mild" form of thrombophilia, 6 to 12 months is advised. If there is a severe underlying thrombosis disorder, warfarin treatment may need to continue indefinitely.
Thrombolysis (removal of the blood clot with "clot buster" medication) has been described, either systemically by injection into a vein or directly into the clot during angiography. The 2006 European Federation of Neurological Societies guideline recommends that thrombolysis is only used in patients who deteriorate despite adequate treatment, and other causes of deterioration have been eliminated. It is unclear which drug and which mode of administration is the most effective. Bleeding into the brain and in other sites of the body is a major concern in the use of thrombolysis. American guidelines make no recommendation with regards to thrombolysis, stating that more research is needed.
Raised intracranial pressure, if severe or threatening vision, may require therapeutic lumbar puncture (removal of excessive cerebrospinal fluid), medication (acetazolamide), or neurosurgical treatment (optic nerve sheath fenestration or shunting). In certain situations, anticonvulsants may be used to try to prevent seizures. These situations include focal neurological problems (e.g. inability to move a limb) and focal changes of the brain tissue on CT or MRI scan. Evidence to support or refute the use of antiepileptic drugs as a preventive measure, however, is lacking.
After return of heart function, there has been a moderately higher risk of death in the hospital when compared to MI patients without PVF. Whether this still holds true with the recent changes in treatment strategies of earlier hospital admission and immediate angioplasty with thrombus removal is unknown. PVF does not affect the long-term prognosis.
Ischemia: A decreased or restriction of circulating blood flow to a region of the brain which deprives neurons of the necessary substrates (primarily glucose); represents 80% of all strokes. A thrombus or embolus plugs an artery so there is a reduction or cessation of blood flow. This hypoxia or anoxia leads to neuronal injury, which is known as a stroke. The death of neurons leads to a so-called softening of the cerebrum in the affected area.
Hemorrhage: Intracerebral hemorrhage occurs in deep penetrating vessels and disrupts the connecting pathways, causing a localized pressure injury and in turn injury to brain tissue in the affected area. Hemorrhaging can occur in instances of embolic ischemia, in which the previously obstructed region spontaneously restores blood flow. This is known as a hemorrhagic infarction and a resulting red infarct occurs, which points to a type of cerebral softening known as red softening.
Treatment is varied depending upon the nature of the case. In severe cases, coronary artery bypass surgery is performed to redirect blood flow around the affected area. Drug-eluting stents and thrombolytic drug therapy are less invasive options for less severe cases.