Stroke

A stroke is a condition where a blood clot or ruptured artery or blood vessel interrupts blood flow to an area of the brain. A lack of oxygen and glucose (sugar) flowing to the brain leads to the death of brain cells and brain damage, often resulting in an impairment in speech, movement, and memory.

The two main types of stroke include ischemic stroke and hemorrhagic stroke. Ischemic stroke accounts for about 75% of all strokes and occurs when a blood clot, or thrombus, forms that blocks blood flow to part of the brain. If a blood clot forms somewhere in the body and breaks off to become free-floating, it is called an embolus. This wandering clot may be carried through the bloodstream to the brain where it can cause ischemic stroke. A hemorrhagic stroke occurs when a blood vessel on the brain's surface ruptures and fills the space between the brain and skull with blood (subarachnoid hemorrhage) or when a defective artery in the brain bursts and fills the surrounding tissue with blood (cerebral hemorrhage). Both result in a lack of blood flow to the brain and a buildup of blood that puts too much pressure on the brain.

The outcome after a stroke depends on where the stroke occurs and how much of the brain is affected. Smaller strokes may result in minor problems, such as weakness in an arm or leg. Larger strokes may lead to paralysis or death. Many stroke patients are left with weakness on one side of the body, difficulty speaking, incontinence, and bladder problems.

Causes of Stroke

An ischemic stroke is the result of blockage in blood flow to the brain caused by a blood clot. The buildup of plaque in the artery wall (atherosclerosis, or "hardening of the arteries") is an underlying cause for many ischemic strokes.
Atherosclerosis is a process in which fatty deposits (plaques) build up inside the blood vessels of the body, particularly in the carotid arteries of the neck, the coronary arteries of the heart, and the arteries of the legs. Atherosclerotic plaques can lead to a stroke by causing blockage of blood flow, or by dislodged plaque material (emboli) that can travel to the brain.
A hemorrhagic stroke is caused by bleeding into the brain (intracerebral hemorrhage) or bleeding around the brain (subarachnoid hemorrhage), which results from the breakage of a blood vessel. Brain hemorrhages may result from uncontrolled high blood pressure, and, in some cases, can be caused by structural problems within the blood vessels (e.g., aneurysms or vascular malformations).
There are numerous risk factors that can cause a stroke.
Factors you can't control are:

• age: The risk of stroke increases with advancing age.
• ethnicity: People of First Nations, African, Hispanic, and South Asian descent have greater rates of high blood pressure and diabetes. These conditions increase the risk of stroke.
• family history: The risk of stroke may be higher if a parent or sibling has had a stroke before the age of 65.
• gender: Men have a higher risk of stroke than women who have not reached menopause.
• prior stroke or transient ischemic attack (TIA): Up to one-third of people who survive a first stroke or TIA will have another stroke within 5 years.

Factors you can control are:

• high blood pressure
• heart disease or atrial fibrillation (irregular heartbeat)
• cigarette smoking
• diabetes
• high cholesterol
• physical inactivity
• high alcohol intake (more than 10 drinks per week for women or more than 15 drinks per week for men)
• stress

Other factors that can lead to a stroke are:

• other medical conditions such as amyloid angiopathy and antiphospholipid antibody syndrome
• use of illicit drugs such as cocaine or LSD
• some medications, such as tamoxifen*, phenylpropanolamine, and thrombolytics

Other factors such as oral contraceptive use, hormone replacement therapy, or pregnancy and childbirth in women with pre-existing medical conditions may increase the risk of stroke in specific cases. Talk to your doctor about risk factors that may be relevant to you and your risk of stroke.

The symptoms of stroke begin suddenly because they are caused by an abrupt interruption of blood flow to an area of the brain. When this happens it only takes a few seconds for that part of the brain to stop functioning

Only a small proportion of strokes produce headache symptoms. However, the sudden onset of a severe headache makes doctors suspect that there is bleeding inside the brain. Because of the high risk of death in these cases, people who come into the emergency room complaining of severe headache are rapidly

screened for the presence of blood in the brain


The severity of stroke symptoms varies depending on the part of the brain that is affected. For instance, strokes that affect areas of the brain which have minimal importance in day to day brain activity typically produce mild or unnoticeable symptoms. By contrast, strokes that affect areas of the brain which have maximal importance in day to day brain activity cause the most debilitating and noticeable symptoms.
For instance strokes affecting one of the smell areas of the brain rarely cause identifiable symptoms. By contrast strokes affecting one of the speech areas of the brain nearly always do.

Treatments and drugs


Emergency treatment for stroke depends on whether you're having an ischemic stroke blocking an artery — the most common kind — or a hemorrhagic stroke involving bleeding into the brain.
Ischemic strokeTo treat an ischemic stroke, doctors must quickly restore blood flow to your brain.
Emergency treatment with medications. Therapy with clot-busting drugs (thrombolytics) must start within 4.5 hours if they are given into the vein — and the sooner, the better. Quick treatment not only improves your chances of survival but also may reduce the complications from your stroke. You may be given:

• Aspirin. Aspirin, an anti-thrombotic drug, is an immediate treatment after an ischemic stroke to reduce the likelihood of having another stroke. Aspirin prevents blood clots from forming. In the emergency room, you may be given a dose of aspirin. The dose may vary, but if you already take a daily aspirin for its blood-thinning effect, you may want to make a note of that on an emergency medical card so doctors will know if you've already taken some aspirin.
  Other blood-thinning drugs, such as heparin, also may be given, but this drug isn't proven to be beneficial in the emergency setting so it's used infrequently. Clopidogrel (Plavix), warfarin (Coumadin), or aspirin in combination with extended release dipyridamole (Aggrenox) may also be used, but these aren't usually used in the emergency room setting.
• Intravenous injection of tissue plasminogen activator (TPA). Some people who are having an ischemic stroke can benefit from an injection of a recombinant tissue plasminogen activator (TPA), also called alteplase, usually given through a vein in the arm. This potent clot-busting drug needs to be given within 4.5 hours after stroke symptoms begin if it's given into the vein. This drug restores blood flow by dissolving the blood clot causing your stroke, and it may help people who have had strokes recover more fully. Your doctor will consider certain risks, such as potential bleeding in the brain, to determine if TPA is the most appropriate treatment for you.

Emergency procedures. Doctors sometimes treat ischemic strokes with procedures that must be performed as soon as possible.

• Medications delivered directly to the brain. Doctors may insert a long, thin tube (catheter) through an artery in your groin and thread it to your brain, and then release TPA directly into the area where the stroke is occurring. The time window for this treatment is somewhat longer than for intravenous TPA but still limited.
• Mechanical clot removal. Doctors may use a catheter to maneuver a tiny device into your brain to physically grab and remove the clot.

Other procedures. To decrease your risk of having another stroke or TIA, your doctor may recommend a procedure to open up an artery that's moderately to severely narrowed by plaque. Doctors sometimes recommend these procedures to prevent a stroke. Options may include:

• Carotid endarterectomy. In a carotid endarterectomy, a surgeon removes fatty deposits (plaques) from your carotid arteries that run along each side of your neck to your brain. In this procedure, your surgeon makes an incision along the front of your neck, opens your carotid artery, and removes fatty deposits (plaques) that block the carotid artery. Your surgeon then repairs the artery with stitches or a patch made with a vein or artificial material (graft). The procedure may reduce your risk of ischemic stroke. However, a carotid endarterectomy also involves risks, especially for people with heart disease or other medical conditions.
• Angioplasty and stents. In an angioplasty, a surgeon inserts a catheter with a mesh tube (stent) and balloon on the tip into an artery in your groin and guides it to the blocked carotid artery in your neck. Your surgeon inflates the balloon in the narrowed artery and inserts a mesh tube (stent) into the opening to keep your artery from becoming narrowed after the procedure.

Hemorrhagic strokeEmergency treatment of hemorrhagic stroke focuses on controlling your bleeding and reducing pressure in your brain. Surgery also may be used to help reduce future risk.
Emergency measures. If you take warfarin (Coumadin) or anti-platelet drugs such as clopidogrel (Plavix) to prevent blood clots, you may be given drugs or transfusions of blood products to counteract their effects. You may also be given drugs to lower pressure in your brain (intracranial pressure), lower your blood pressure or prevent seizures. People having a hemorrhagic stroke can't be given clot-busters such as aspirin and TPA, because these drugs may worsen bleeding.
Once the bleeding in your brain stops, treatment usually involves bed rest and supportive medical care while your body absorbs the blood. Healing is similar to what happens while a bad bruise goes away. If the area of bleeding is large, surgery may be used in certain cases to remove the blood and relieve pressure on the brain.
Surgical blood vessel repair. Surgery may be used to repair certain blood vessel abnormalities associated with hemorrhagic strokes. Your doctor may recommend one of these procedures after a stroke or if you're at high risk of a spontaneous aneurysm or arteriovenous malformation (AVM) rupture:

• Surgical clipping. A surgeon places a tiny clamp at the base of the aneurysm, to stop blood flow to it. This can keep the aneurysm from bursting, or it can prevent re-bleeding of an aneurysm that has recently hemorrhaged.
• Coiling (endovascular embolization). In this procedure, a surgeon inserts a catheter into an artery in your groin and guides it to your brain using X-ray imaging. Your surgeon then guides tiny detachable coils into the aneurysm (aneurysm coiling). The coils fill the aneurysm, which blocks blood flow into the aneurysm and causes the blood to clot.
• Surgical AVM removal. Surgeons may remove a smaller AVM if it's located in an accessible area of your brain, to eliminate the risk of rupture and lower the risk of hemorrhagic stroke. However, it's not always possible to remove an AVM if it's too large or if it's located deep within your brain.

Stroke recovery and rehabilitationFollowing emergency treatment, stroke care focuses on helping you regain your strength, recover as much function as possible and return to independent living. The impact of your stroke depends on the area of the brain involved and the amount of tissue damaged. If your stroke affected the right side of your brain, your movement and sensation on the left side of your body may be affected. If your stroke damaged the brain tissue on the left side of your brain, your movement and sensation on the right side of your body may be affected. Brain damage to the left side of your brain may cause speech and language disorders. In addition, if you've had a stroke, you may have problems with breathing, swallowing, balancing and vision.
Most stroke survivors receive treatment in a rehabilitation program. Your doctor will recommend the most rigorous therapy program you can handle based on your age, overall health and your degree of disability from your stroke. Your doctor will take into consideration your lifestyle, interests and priorities, and availability of family members or other caregivers.
Your rehabilitation program may begin before you leave the hospital. It may continue in a rehabilitation unit of the same hospital, another rehabilitation unit or skilled nursing facility, an outpatient unit, or your home.
Every person's stroke recovery is different. Depending on your condition, your treatment team may include:

• Doctor trained in brain conditions (neurologist)
• Rehabilitation doctor (physiatrist)
• Nurse
• Dietitian
• Physical therapist
• Occupational therapist
• Recreational therapist
• Speech therapist
• Social worker
• Case manager
• Psychologist or psychiatrist
• Chaplain