One in Four People Will Experience a Stroke in Their Lifetime - Most Can Be Prevented

Stroke is the second leading cause of death in the Western world and the leading cause of disability. Every year, approximately 20,000 new cases of stroke occur in Israel. So, who is at risk and what are the symptoms? All the answers for International Stroke Day taking place this week.

What is a Stroke?

A stroke is caused by a disruption of blood flow to a specific part of the brain. This event usually occurs due to a blockage of a blood vessel by a blood clot or the narrowing of vessels leading blood to the brain (ischemic stroke - about 85% of stroke cases). In a minority of cases, it results from brain bleeding due to damage to a cerebral artery wall (hemorrhagic stroke - about 15% of stroke cases).

A stroke causes permanent damage to brain tissue due to a sudden or temporary decrease in blood supply to a specific brain region. During an ischemic stroke, the brain tissue that suffers from a lack of oxygen loses about two million neurons every minute, a rapid process that ends with the death of all neurons in the blocked area of blood supply.

Who is at Risk?

The risk of stroke increases with age and with the presence of vascular risk factors such as high blood pressure, diabetes, high blood fats and cholesterol, obesity, smoking, excessive alcohol consumption, or drug use. Several pathological conditions cause strokes through different mechanisms, primarily atherosclerosis, small cerebral vessel disease, and a common heart rhythm disorder called atrial fibrillation. This rhythm disorder, sometimes unnoticed, significantly and markedly increases the risk of stroke. The stroke mechanism in atrial fibrillation likely involves irregular blood flow in the left atrium of the heart, especially in a part called the "appendage." These blood clots break off and travel to the brain, causing a stroke. In diagnosing atrial fibrillation, a risk stratification called CHADS-VASC must be performed, and a blood-thinning treatment must be tailored, usually involving daily oral anticoagulant therapy. Stroke mechanism evaluation begins as early as the initial assessment in the emergency room and can continue for days to weeks, including CT with contrast to visualize neck and brain arteries, CTA, carotid doppler to visualize narrowing of neck arteries, MRI brain, echocardiogram to look for a cardiac source of embolism, heart rhythm recording to look for atrial fibrillation, and more.

Getting Younger

For reasons not entirely clear, the average onset age of stroke is gradually decreasing in the Western world, and this tragic event affects many at the peak of their lives. Approximately 10-15% of stroke cases affect people younger than 50, and strokes in even younger individuals, in their 30s and 40s, are not uncommon and are part of the routine work of stroke units in Israeli hospitals. The causes and stroke mechanisms in young people, especially in the absence of classic vascular risk factors, are varied and include:

• Cervical artery dissection: Dissection is a separation between the layers of the blood vessel wall, occurring against the background of atherosclerosis, neck trauma, or extreme neck bending. Sometimes dissection may occur spontaneously due to an abnormal congenital vessel structure.
• Hypercoagulability: Many cases of stroke at a young age are caused by conditions of hypercoagulability. About 15% of the population suffers from inherited or acquired hypercoagulability and is at increased risk of venous (primarily venous thrombosis) and arterial clots. Estrogen-based contraceptive pills and other medications carry an increased risk of clot formation, especially when combined with smoking. Often, an additional risk factor is needed to reach the threshold for clot creation.
• Patent Foramen Ovale (PFO) is a congenital defect in the interatrial septum through which clots can travel from the venous system straight to the arterial system and the brain. In young individuals without risk factors who have developed a stroke, it is a common stroke mechanism to be identified and treated with heart catheterization to close the defect.
• Autoimmune inflammatory diseases such as joint and connective tissue disorders, vascular inflammations, or intestinal inflammations carry an increased risk for thrombotic events and are part of the investigation done in search of stroke causes in young people.

What are the Symptoms of a Stroke??

A stroke can manifest in a wide range of clinical symptoms. It may present as weakness of a limb or one side of the body, weakness of facial and speech muscles on one side of the face or facial distortion, difficulty producing or understanding speech, sudden loss of part of the visual field in one or both eyes, instability, and even confusion or altered consciousness. Less common stroke events may present more subtly, but in any case, a neurological examination performed skillfully in real time can determine the source of sudden functional deficiencies in the nervous system and reach a quick diagnosis of stroke. Interventional actions in real-time during the first hours of a stroke can dramatically alter the clinical course and the degree of permanent disability left behind. There is great importance in identifying stroke events immediately upon occurrence and rushing the suffering individual to receive urgent medical treatment at one of the emergency departments (formerly "Emergency Room") of hospitals in Israel.

What is the Treatment?

Immediately with the onset of a stroke, a narrow and precious time window opens, during which brain tissue can still be saved before its final death. The area in the brain, caught between life and death, known as the "penumbra," suffers from a severe lack of blood supply and does not function but can still be saved by restoring blood flow to it, hence the great importance of rapid arrival at the hospital, with assessment and treatment by the MDA teams trained for these situations.

Treatments can only be given if most of the involved brain tissue has not yet undergone irreversible damage and can be saved, and such treatment decisions are made in real-time by senior neurologists specializing in stroke treatment in collaboration with brain interventionists. After a stroke, a short hospitalization is needed to manage post-stroke complications, investigate the stroke cause, and tailor preventive treatment. Subsequently, home rehabilitation or hospitalization in a rehabilitation facility is required. The aim of rehabilitation is to return the individual to the best possible functional status and teach them to live with potential new limitations.

Dr. Rani Barnea is a senior neurologist on the stroke team and the neurology department at Rabin Medical Center - Beilinson Campus.