Stroke / Brain attack

There are two different types of stroke: an ischemic stroke, i.e. reduced blood flow to the brain, and a hemorrhagic stroke, i.e. a cerebral hemorrhage. Both forms can lead to impairments throughout the body, depending on the area of the brain in which the stroke has occurred. This is because each brain region controls different bodily functions.

What is a stroke?

Those affected often feel as if the stroke has come suddenly, as if with a single blow. This is why this dramatic dysfunction in the brain is also known as a stroke. In around 85 percent of cases, it occurs because a blood vessel in the brain is blocked. This means that the blood supply in the underlying part is interrupted and the associated bodily functions are literally paralyzed, resulting in paralysis, speech disorders, dizziness, visual disturbances and other neurological deficits. If the blood vessel is not reopened within a short time, these disorders persist. In about 15 percent of cases, however, it is a hemorrhage in the brain: a vessel has burst, which increases the pressure in this area. Strokes mostly affect older people, around four-fifths of whom are over 60 years old. But younger people can also have a stroke.

Stroke: causes and risk factors

Both forms of stroke, the more common ischemic stroke and the hemorrhagic stroke, have different causes.

Ischemic stroke

In an ischemic stroke, a blood vessel in the brain is blocked. As a result, the underlying tissue is more or less cut off from the blood supply, and oxygen and sugar are no longer sufficiently available. If this condition lasts longer, the undersupplied area dies off. In addition to various rare causes, there are two common mechanisms for vascular congestion:

• Often, arteriosclerosis has been present for years. A blood clot (thrombus) can form at a narrow point in the vessel and block the bloodstream (local thrombotic occlusion) or the blood clot can break loose (embolus) and then block a smaller vessel further distally (=in the direction of blood flow) (arterio-arterial embolism).
• A clot forms in the heart, which then travels via the bloodstream to the brain and blocks a vessel there (cardioembolism). This can occur with cardiac arrhythmias such as atrial fibrillation.

Hemorrhagic stroke

The most common cause of a hemorrhagic stroke is high blood pressure. The blood vessels are permanently overloaded by the high blood pressure and can tear. If this happens in the brain, a cerebral hemorrhage occurs. The escaping blood exerts mechanical pressure on the surrounding area. The surrounding nerve cells are damaged. In addition to high blood pressure, there are rare causes of cerebral hemorrhage, such as vascular malformations in the brain.

Risk factors for a stroke

There are various factors that significantly increase the risk of a stroke. You cannot influence two of them. These are:

• Age: Most of those affected are over 60 years old.
• Family predisposition: If one or even several of your relatives have already had a stroke, your own risk may also be increased.

However, there are four times as many other known risk factors for which you can reduce the risk of a stroke yourself with medical support:

• Stop smoking
• Optimal control of high blood pressure (hypertension) through diet, exercise and medication
• Optimal control of diabetes (diabetes) through diet, exercise and medication
• Optimum adjustment of blood lipid levels through diet, exercise and medication
• Pronounced overweight: The waist-to-hip ratio (WHR) is important here, which should be less than 0.85 for women and less than 1 for men
• Increased physical activity
• Reducing alcohol consumption
• Reduction of psychosocial stress.

Stroke symptoms: not just paralysis

There are a number of signs that may indicate a cerebral infarction. They are so different because they depend on which area of the brain is affected by the stroke and which bodily functions are impaired by the resulting deficiency. These are mostly neurological deficits. The most common symptoms are

• A feeling of weakness (paresis) or total loss of muscle strength (plegia). Typically, these symptoms only occur in one half of the body, as the stroke usually only affects one half of the brain. The opposite side of the body is then affected by the feeling of weakness. Example: The stroke affects the right side of the brain, paresis or plegia occur in the left arm and leg.
• Sensory disturbances such as numbness, affecting one half of the face and one arm
• Slurred speech, slurred speech and difficulties with communication show the range of speech and language disorders.
• Dizziness, unsteady gait
• Swallowing disorders
• Visual disturbances
• Confusion
• Drowsiness or even unconsciousness (less common)
• Very severe, sudden onset of headache and vomiting

The symptoms usually occur suddenly. Exception: They wake up in the morning with symptoms (wake-up stroke), i.e. they did not register when they started because they were asleep at the time. But it doesn’t matter whether you notice these symptoms from one minute to the next or only in the morning, whether they are dramatic or mild: You should always call the emergency services (144) immediately or have them call you. Because every minute counts when treating a stroke. A stroke can be life-threatening. And the more time that passes before treatment begins, the greater the risk of permanent damage.

Stroke: Diagnosis with us

In the event of neurological deficits, the ambulance service usually takes the patient immediately to a specialized center (stroke unit, stroke center). As a stroke center, the USZ offers all the possibilities of modern stroke care at any time of day or night. Specialists from neurology, neuroradiology and neurosurgery work closely together on an interdisciplinary basis. Other hospitals with a stroke unit carry out the necessary diagnostics and transfer patients to the stroke center if necessary. The diagnosis must be made very quickly and consists of a neurological examination to clarify the symptoms in more detail: Computed tomography or MRI. The CT scan helps to determine whether it is ischemia or a cerebral hemorrhage, i.e. whether a blood vessel is blocked or has burst. This distinction is important because the acute treatment of these two forms of stroke is very different.

In the further course, the cause of the stroke must then be clarified with the help of:

• Ultrasound examination of the neck vessels
• Ultrasound examination of the heart
• Cardiac waveform (over at least 48 hours) to detect whether cardiac arrhythmia is present.

Stroke: prevention, early detection, prognosis

The risk of a stroke can be reduced if you control and treat the common risk factors in particular. We can advise and help you with this as part of our specialized stroke consultation hours:

1. Prevent high blood pressure from developing – and if it doesn’t, it should at least be well controlled. This means that, in consultation with us, you can lower your blood pressure by taking the right dose of medication and adopting a healthy lifestyle.
2. Protect yourself from high blood lipid or sugar levels with a healthy diet, exercise and, if necessary, medication, which we will work with you to optimize.
3. Stop smoking.
4. Make sure you exercise regularly.
5. If you sometimes have palpitations or other pulse irregularities, please have them checked by a cardiologist.
6. Avoid stress.

In addition, an ultrasound examination of the blood vessels, such as the carotid artery, can show whether the blood vessels are in good condition or whether the innermost layer of the vessel wall has changed – an important indication of arteriosclerosis. Of course, regular blood pressure checks complement the stroke prevention program.

Course and prognosis of a stroke

Ultimately, a stroke can be life-threatening. In industrialized nations such as Switzerland, stroke is the third leading cause of death. It can lead to lifelong disabilities, but also to dementia. This results in enormous costs for the healthcare system (direct healthcare costs alone amount to over CHF 700 million per year).

A stroke is therefore always a medical emergency and treatment should start as soon as possible. Every minute counts. If therapy is started as soon as the first symptoms appear and only a small area of the brain is affected, the stroke can, in the best case scenario, have no consequences.

Unfortunately, sometimes the therapy does not work quite as quickly, and more or less impairing functional disorders remain – such as speech disorders and partial paralysis. However, with the appropriate neurorehabilitation, these can disappear or at least be alleviated over time. The brain develops the ability for intact areas to learn and take over the tasks that were lost with the damaged areas. However, this often requires a lot of time, but also the strength, will and motivation of those affected.

Self-help groups

The exchange with people who are affected by the same disease can be a great support in coping with the disease. Advice on finding a suitable self-help group is available from Selbsthilfe Zürich. Self-Help Zurich and the University Hospital Zurich are cooperation partners in the national project “Health literacy thanks to self-help-friendly hospitals”.

Stroke: Treatment - the sooner the better

Depending on whether it is an ischemic stroke or a hemorrhagic stroke, the therapies differ fundamentally.