Stroke and Medical Drugs Treatment

Introduction

Although death rates from stroke have declined over the recent years, it remains the third leading cause of death in the United States. On average, someone in the United States has a stroke every 40 seconds. And, every 3 to 4 minutes, someone dies of a stroke. Strokes can occur at any time, regardless of age, gender or race. Most stroke symptoms are not associated with pain, causing people to delay medical treatment. Signs and symptoms of stroke can range from difficulty with speech to sudden numbness or weakness in the face or limbs. During a stroke, two million brain cells die every minute, increasing the risk for permanent brain damage, disability and death. Therefore, it is important to recognize signs and symptoms of a stroke in order to seek immediate medical attention.

What is it?

There are two main types of strokes:

1. An ischemic stroke occurs when there is a decrease in the amount of blood and oxygen delivered to the brain as a result of blood clots or build up of fat in the blood vessels.
2. A hemorrhagic stroke occurs when a blood vessel ruptures, causing blood to leak into the brain.

About 87% of all strokes are ischemic in nature, with hemorrhagic stroke occurring only 13% of the time. Ischemic strokes are more common because there are more causes or risk factors associated with ischemic strokes, such as high cholesterol, heart disease, other heart conditions (such as heart failure), and high blood pressure. On the other hand, hemorrhagic strokes may occur when there is trauma to the head or high blood pressure, causing a rupture in a blood vessel.

Transient ischemic attacks (TIAs) are "mini strokes" that have stroke-like symptoms with no lasting damage. It occurs when the blood supply to the brain is temporarily interrupted. TIA symptoms, which usually occur suddenly, are similar to those of a full-blown ischemic stroke, but they do not last as long. Symptoms of a TIA may last for several minutes to 24 hours without leaving permanent effects. It is possible to have more than one TIA, and the recurrent signs and symptoms may be similar or different. People who have had a TIA are more likely to have a stroke than those who have not had a previous TIA.

TIAs occur before an ischemic stroke in about 15% of cases. After a TIA, the 90-day risk of experiencing a stroke is approximately 3% to 17%, but the risk is the highest within the first 30 days. Within one year of a TIA, up to one-fourth of people who have an ischemic or hemorrhagic stroke die.

What causes it?

Ischemic Strokes

There are two main causes of ischemic strokes:

1. Cerebral thrombosis: Thrombosis is the formation of a blood clot (or thrombus) at the blocked portion of a blood vessel. Atherosclerosis (hardening of the blood vessels as a result of fatty buildup and cholesterol plaques on the vessel wall) causes blood vessels to narrow and restrict blood flow, which can lead to the formation of a blood clot. If a blood clot develops in a blood vessel that supplies blood to the brain, the blood and oxygen supply to the brain can be diminished or completely blocked leading to an ischemic stroke.
2. Cerebral embolism: An embolism is a dislodged blood clot that forms at another site in the circulatory system, usually in the heart or in the large arteries in the upper chest and neck. The blood clot then traveles through the blood vessels and becomes wedged in an artery. In about 15% of all strokes, the emboli are blood clots that originally formed in the heart as a result of a rhythm disorder known as atrial fibrillation -- a rapid, irregular beat in the upper chambers of the heart (the atria). As a result of the irregular pumping, some blood may pool in the heart chamber and form a clot, which can then break off and travel to the brain as an emboli, causing an ischemic stroke.

Hemorrhagic Stroke

A hemorrhagic stroke occurs when a blood vessel that is weakened ruptures, causing blood to leak into the surrounding areas of the brain. Blood vessels usually rupture as a result of high blood pressure combined with arteriosclerosis (hardening of the blood vessels due to fatty buildup and cholesterol plaques on the vessel wall), which can place too much pressure on the blood vessel walls. The blood can accumulate and increase the pressure surrounding the brain tissue.

The two types of hemorrhagic strokes are:

1. An intracerebral hemorrhage occurs when a faulty blood vessel in the brain bursts, flooding the nearby areas of the brain. The most common sites are the basal ganglia (an area in the brain responsible for controlling voluntary movements and establishing postures), the cerebellum (an area in the brain that provides coordination of finely executed complex movements, including speech) the thalamus (an area in the brain that is the center of pain, touch, and temperature) and the pons (an area in the brain that acts as a relay station for messages in the brain and is important centers for regulating breathing).
2. A subarachnoid hemorrhage occurs when a blood vessel in the brain bursts, causing sudden bleeding into the space between the middle lining of the brain (the arachnoid membrane) and the brain itself. A subarachnoid hemorrhage causes sudden, severe pain in the head; a person may describe it as "the worst headache I have ever had."

Who has it?

As mentioned previously, stroke is the third leading cause of death in the United States and a leading cause of long-term disability. In 2006, the American Stroke Association estimated that in the United States nearly 157,000 people die from a stroke each year, and that cumulatively 4.6 million people survived a stroke. Each year, it is estimated that 795,000 people will experience a new or recurrent stroke.

Strokes can occur in both women and men and in all ethnic groups although certain groups are at higher risk for dying from strokes (see "What are the risk factors?"). African Americans have almost twice the risk of an initial stroke as compared with Caucasians. The incidences of strokes in males are greater than in women at younger ages, but not at older ages. In 2004, women accounted for 61% of U.S. stroke deaths.

What are the risk factors?

Risk factors are characteristics that may increase your chance for developing a condition. For ischemic and hemorrhagic stroke, risk factors include the following:

Risk factors that can not be changed or controlled:

• Age -- The risk for stroke doubles each decade after the age of 55.
• Gender -- Men have about a 30% higher risk for stroke than women do until the age of 55 years. After the age of 55 years, the risk is the same for men and women.
• Race -- Higher death rates from stroke occur in African Americans, Asian-Pacific Islanders, and Hispanics than in whites as a result of increased incidence of high blood pressure.
• Heredity -- The risk for stroke is greater if a parent, brother, or sister has a stroke or transient ischemic attack.

Risk factors that can be changed or that can be controlled:

• High blood pressure
• Heart disease
• TIAs
• Diabetes
• High cholesterol
• Atrial fibrillation
• Cigarette smoking
• Alcohol
• Illicit drug use
• Lifestyle factors - inactivity, obesity, poor diet and stress
• High estrogen oral contraceptives, especially in women over 35 years who smoke and women over 40 years who have hypertension or diabetes
• Sickle cell disease

What are the symptoms?

Ischemic stroke

General symptoms of an ischemic stroke include a sudden onset of the following:

• Numbness, weakness, or inability to move (paralysis) of face, arm, or leg, usually on one side of the body
• Trouble seeing in one or both eyes (such as dimness, blurring, double vision, or loss of vision)
• Confusion, trouble speaking or understanding
• Trouble walking, dizziness, loss of balance or coordination
• Severe headache with no known cause

Symptoms can develop suddenly (within minutes) and may also progress over hours to days. Symptoms of an ischemic stroke may be so minor that they often get ignored or go unnoticed, but medical attention should not be delayed.

TIA

General symptoms of TIA include sudden onset of the following:

• Numbness or weakness in the face or limbs
• Dimming or loss of vision in one eye
• Unexpected falls
• Unexplained dizziness
• Nausea
• Double vision
• Drowsiness

The difference between a TIA and an ischemic or hemorrhagic stroke is the duration of the symptoms; TIA symptoms usually disappear after 10 to 20 minutes and last no longer than 24 hours. For instance, a person experiencing a TIA may experience temporary numbness in the limbs, loss of vision or unexplained dizziness for a few minutes, or even up to 24 hours, but will likely recover the next day. On the other hand, a person who has an ischemic stroke may have numbness on one side of the body, loss of vision, headache or confusion, which will not disappear the next day. This would also apply to a person having a hemorrhagic stroke; they may experience a severe headache, changes in mental status or dizziness that will not disappear after 24 hours.

Hemorrhagic stroke

General symptoms of a hemorrhagic stroke include sudden onset of the following:

• Headache (severe and in a specific area)
• Nausea and vomiting
• Neck stiffness
• Dizziness
• Seizures
• Changes in mental state, such as irritability, confusion, and possibly, unconsciousness

Hemorrhagic strokes often occur during the daytime and during physical activity, but this is not always true. Symptoms of a hemorrhagic stroke typically begin suddenly (within seconds) and progress over several hours.

People with very high, uncontrolled blood pressure may have one or more symptoms before they have a hemorrhagic stroke, including the following:

• Severe headache in the back of the head or top of the neck
• Dizziness or fainting
• Tingling or numbness in an arm or leg, or an inability to move an arm or leg that comes and goes

How is it treated?

Strokes can be treated and 80% of strokes are preventable. At the moment, no treatment can cure a stroke, and most people will have some form of residual damage, which will vary from person to person. Residual damage can range from a slight limp to paralysis on one side of the body. Prevention will be the key to avoid further damage and subsequent strokes.

Prevention:

Antihypertensive agents: Reducing even mild to moderate blood pressure has been shown to lower the risk of stroke.

Cholesterol lowering agents: These agents -- "statins" like Zocor, Lipitor, Crestor, Lescol, Mevacor and Pravachol -- reduce the risk of stroke in people with existing coronary artery disease.

Treatment of Atrial Fibrillation (irregular heartbeat): The main goal of treatment for atrial fibrillation is to prevent blood clots from forming by first restoring and then maintaining normal heart rhythm.

Treatment for ischemic stroke:

Acute Treatment:

• An acute ischemic stroke is usually treated with a thrombolytic agent, which is considered to be a first-line treatment. Thrombolytics, sometimes called "clot busters," dissolve the blood clot that is blocking the flow of blood through the blood vessel. The use of thrombolytics may however, increase the risk of an intracranial hemorrhage (bleeding in the brain). Due to this increased risk for bleeding, there are several specific criteria that a person must meet before thrombolytic therapy can be given. One of the key criteria is that thrombolytics need to be administered within a certain time frame after stroke symptoms are initially recognized. Therefore, it is extremely important for the person or family members to recognize the symptoms of stroke and to seek medical attention immediately - - at the very least within 3 hours of the onset of stroke symptoms to qualify for thrombolytic therapy. Call 911 if you witness anyone having a stroke because time is of the essence.
• Aspirin is another important agent in the treatment of an acute ischemic stroke. Aspirin should be given more than 24 hours after the thrombolytic, but within 48 hours of symptoms. Early aspirin use has been shown to decrease long-term death and disability in stroke patients.

Chronic Treatment:

• After hospitalization, most patients will need to be placed on an antiplatelet or an anticoagulant, as well as other medications to control blood pressure and lower cholesterol to prevent another stroke. Anti-platelets and anticoagulants are important after a stroke because they interfere with the blood's ability to clot; this can prevent blood clots that may form in the heart or in the blood vessels, which will help reduce your chances of another stroke.
• Medications that prevent blood from clotting are also used in people who have had a TIA and are at risk for stroke.
• Carotid endarterectomy is a surgical procedure used to treat and prevent an acute ischemic stroke. This is an effective procedure in protecting against a first stroke in patients with severe stenosis (constriction or narrowing of a blood vessel by 70%-99%) of the main blood vessel in the brain.
• Angioplasty and stenting are common procedures used in some individuals to help widen the arteries. During the procedure, a catheter (a long, hollow tube) is inserted in an artery near the groin until it reaches the artery that is narrowed. A tiny balloon at the end of the catheter is inflated to flatten the fatty buildup against the wall of the artery. Afterwards, a wire mesh stent (small mesh tube) is placed in order to keep the artery open and prevent it from narrowing.

Treatment for hemorrhagic stroke:

• A cerebral hemorrhage is associated with extremely high death rates. It can be treated with either surgery or medical intervention and there is currently no medical consensus as to which treatment is best.
• Surgical treatment involves removing the large clot from the area. The blood clot (referred to as a hematoma) size and level of consciousness of the patient are critical. Patients who are awake and have small hematomas (less than 3 centimeters diameter or less than 20 mls) will usually improve without surgery, whereas comatose patients with large hematomas (greater than 6 centimeters diameter or greater than 80 mls) will usually do very poorly, regardless of management. The best candidates for surgery may be patients with moderate to large hematomas who are still awake or conscious.
• Medical treatment involves monitoring blood pressure while providing adequate blood flow to the brain. If increased pressure is suspected treatment with intravenous mannitol (which reduces the pressure and excess fluids by reducing the clot) with or without furosemide (a diuretic that reduces pressure and removes excess water) may be helpful.
• A subarachnoid hemorrhage can be treated with either surgery or medical treatment. Surgical treatment involves not only finding the site of the bleeding, but also stopping the bleeding in the brain. Currently, surgery in all patients in good neurological condition (meaning there are no other complications affecting the nervous system) would be the treatment of choice, if the site is surgically easy to get to and there are no other medical complications present. Medical treatment involves normalizing blood pressure, bedrest, analgesics (acetaminophen) to relieve headache and nimodipine (Nimotop) (to reduce pressure and decrease brain cell loss). Nimodipine has been shown to reduce death and hospitalizations.

Drug classes used to treat Stroke

• Antiplatelets
• Oral Anticoagulants
• Salicylates
• Thrombolytic Agents
  

What is on the horizon?

New therapy for prevention of TIAs and stroke includes a number of new and emerging interventions. Different strategies that restore blood flow to the brain, including longer-acting thrombolytics, anti-platelets and laser-guided clot removal are being researched. Therapies that help reverse the effects of an acute stroke are also being investigated. Researchers are also investigating the possibility of extending the time frame for administering thrombolytic therapy.