Stroke

What is a stroke?

Cardiovascular and cerebrovascular disorders are major threats to healthy living. These conditions are more prevalent at old age.The most severe cardiovascular disorder that is affecting the lives of millions across the world is “stroke”. According to the global statistics by the World Stroke Organization, about 7,95,000 people suffer from stroke annually.

Although stroke and other cardiovascular conditions are common in all ethnic groups, the African Americans are more prone to these diseases than the white Americans or the Asians. Stroke is one of the leading causes of emergency hospitalization and 5^th leading cause of death at present. Cardiovascular diseases cause around 30% of deaths.

Health organizations all over the world are working together to reduce the global morbidity and mortality rates due to stroke.

Defining a stroke

A stroke is roughly defined as a “brain attack” that occurs when the blood supply to the brain is disrupted for a short period of time.

It occurs due to narrowing of the arteries leading to the brain.

Under acute cardiovascular conditions, the arteries leading to the brain or the blood vessels present in the brain may rupture or get obstructed due to blood clots.

The brain stops receiving oxygen in such cases and fails completely.

Three main conditions are observed in those cases- generation of a blood clot(s) within the blood vessels leading to the brain (thrombosis), transfer of the clots from the site of generation to other sites (embolism) or excessive narrowing of the arteries leading to the brain (stenosis).

Depending on the duration of the stroke, the death of a large percentage of the brain cells occurs during a stroke. Stroke is also termed as cerebrovascular disease or apoplexy.

What are the causes and risk factors for stroke?

Before discussing the causes of stroke, it must be noted that stroke does not build in a day.

Numerous physiological factors and medical conditions progressively lead to the occurrence of stroke over a period of time. The general causes of stroke are described below-

Age: Aged people, usually above the age of 65 are more prone to stroke and associated disorders. This occurs due to natural degeneration of the arterial system that disrupts the normal mechanism of blood flow to the brain. In some rare cases, strokes are also observed in new-borns especially in the perinatal stage (last phase of pregnancy) and within the first few weeks after birth.

Hypertension: This condition is characterized by elevated blood pressure that in turn increases pressure on the walls of the arteries leading to the brain. Patients suffering from high blood pressure are 2-4 times more prone to stroke than normal healthy people.

Heart diseases: Different types of heart diseases like coronary artery disease, peripheral artery disease, atherosclerosis and atrial fibrillation may originate due to degeneration of arterial walls and malfunctioning of the heart valves (causes reverse flow of venous blood) and heart chambers. All of the above conditions can collectively lead to stroke.

Diabetes: Patients with diabetes experience severe damages to the blood vessels in different parts of the body, including the brain. Elevation of glucose levels in the blood leads to more serious pathological conditions. These conditions can lead to stroke.

Cholesterol: People suffering from high cholesterol conditions have an excess fat deposition in the body tissues and blood vessels. These people develop atherosclerosis at some point in time. This affects the brain after a certain time and may lead to stroke and death.

Obesity: Overweight people tend to have excess fat cells and deposition of fat in the walls of the blood vessels, muscles, and arteries. This increases risks of cardiac arrest and stroke.

Gender: Men usually have higher risks of having strokes (46%) at an early age than women. Women develop strokes at a much later age. It has also been observed that strokes in women lead to more deaths than in men.

Ethnicity: African Americans and Hispanic Americans often suffer from sickle cell disease that causes arterial obstruction due to narrowing of arteries. Hence they are at higher risks of stroke than white Americans or Caucasians.

Substance abuse: Excessive cigarette smoking and alcoholism may lead to localized inflammation of arterial walls (an aneurysm) and lead to stroke due to arterial blockage.

What are the main symptoms of stroke?

Stroke is easily identified through the following symptoms-

• Face drooping: One side of the face feels numb and may droop abnormally.
• Muscle weakness: The person finds difficulty raising both arms at an equal level. One of the arms drops.
• Speech problems: Speech becomes slurry during or after a stroke.
• Loss of balance
• Bowel and bladder incontinence
• Problems in swallowing
• Paralysis

What are the different types of stroke?

Strokes are categorized into two types. These are elaborated below-

• Ischemic stroke: Ischemic stroke is the type of stroke caused due to reduced or complete lack of supply of blood to the brain. It has two subtypes-
• Thrombotic strokes: Plaque formation within arteries to the brain cause arterial blockage. This leads to thrombotic strokes.
• Embolic strokes: These types of strokes result from the blood clots that travel to a site away from the site of origin and block the arteries present in that region.
• Hemorrhagic stroke: Rupture of a weak blood vessel within the brain or in the vicinity of the brain causes hemorrhagic stroke. It has two subtypes, Intracerebral hemorrhage:Here, leakage of blood from ruptured vessels occurs within the brain. Subarachnoid hemorrhage: In this case, the leaked blood spreads within the space between the two membranes surrounding the brain.

Diagnosis of stroke

Doctors usually recommend the following diagnostic techniques for strokes and associated complications-

• CT scan and MRI scan of the brain
• Cerebrospinal fluid analysis (through lumbar puncture)
• Electrocardiogram
• Angiography
• Ultrasound
• Blood flow studies

Treatment & Prevention

Stroke can be broadly classified into two categories – ischemic and hemorrhagic; treatment for each category is different. Ischemic stroke is treated by facilitating adequate blood supply to the brain.

This is achieved by administering drugs which prevent internal blood clots from forming.

Surgical method includes angioplasty and insertion of heart stent.

Hemorrhagic stroke is completely opposite, it occurs when blood leaks into the brain.

Thus treatment for this involves controlling blood pressure and constriction of blood vessels. Blood-thinning drugs are useful in such cases. Successful recovery from stroke involves speech therapy, occupational therapy, and group therapy which help in the rehabilitation of the patient. Many patients undergo depression after suffering a stroke; group therapy sessions that address this issue can be very helpful.

In the recent years, incidences of strokes have increased steadily. This has worried doctors all over the world. Health organizations worldwide are spreading mass awareness related to the effects of cardiovascular and cerebrovascular diseases to reduce the current health burden.

TL;DR?

References