Stroke:
causes, symptoms and treatment

Stroke is caused by the sudden discontinuation of the bloody supply in parts of the brain. Due to the lack of blood, the affected nerve cells (neurons) are deprived of oxygen and may die. Every stroke is an emergency. If they are not treated quickly enough, strokes can lead to disability or even death.

In Switzerland, around 20,000 people suffer a stroke every year. It is slightly more common in men than in women. More than three-quarters of all those affected are over the age of 60, but in rare cases a stroke may even occur in children.

A stroke is also known as a cerebral infarction, apoplexy or cerebrovascular insult (CVI).

A stroke usually occurs unexpectedly and suddenly. Only occasionally are there warning signs for a stroke. These include a short-term circulatory disorder in the brain called a transient ischaemic attack, or TIA for short.

Signs of TIA include sudden impaired speech or vision or signs of paralysis. A TIA is not always followed by a stroke. And when it is, a stroke can often occur weeks or months later. In rare cases, sudden hearing loss may be a sign of a stroke.

The signs that a stroke produces depend on the region of the brain where it occurs. Symptoms appear suddenly in most cases and often affect balance, speech or vision. Typical symptoms include:

• Paralysis (usually on one side of the body)
• Numbness
• Dizziness, uncertainty when walking
• Impaired vision (e.g. double vision)
• Speech disorders (e.g. unclear speech)
• Problems swallowing
• Feeling weak, loss of muscle strength
• Dizziness, confusion
• Severe headaches
• Vomiting

There are two main causes of a stroke:

• In about eight out of ten cases, a stroke is caused by a blood clot that stops the blood supply to brain cells by blocking blood vessels. The clot is often the result of arteriosclerosis (vascular calcification). This type of stroke is called an ischaemic stroke.
• Rarely, the cause is a cerebral haemorrhage, often as a result of greatly increased blood pressure, the intake of anticoagulants, or a congenital malformation of the blood vessels. This type of stroke, a brain haemorrhage, is called haemorrhagic stroke and also leads to a lack of blood in the regions behind the bleeding. The resulting pressure can also damage the brain.

Various factors can increase the possibility of a cerebral infarction. Risk factors include:

• Cardiovascular diseases (such as arteriosclerosis or atrial fibrillation) in which blood clots can form
• Advanced age
• High blood pressure
• Use of anticoagulants (blood thinners) – this reduces the risk of a blood clot but increases the risk of bleeding
• Genetic predisposition
• Smoking
• Excessive alcohol consumption
• Diabetes
• Fat metabolism disorders
• Obesity
• Lack of exercise
• Frequent snoring with pauses in breathing (sleep apnoea)
• Migraine with aura
• Birth control medications

Many of these factors can be actively influenced. By not smoking, living a healthy lifestyle with lots of exercise and eating a balanced diet, you can reduce your risk of suffering a stroke.

Stroke is a race against time. Every stroke is an emergency. The emergency services (telephone number 144) must therefore be contacted as soon as possible. Until the emergency services arrive, the patient should lie down without raising their legs and they should not receive any medication.

Ideally, the first stroke treatment should take place shortly after the seizure in a specialised treatment unit (stroke unit) belonging to a hospital or in a larger stroke centre. This is where neurologists and other medical specialists in stroke care work as a team.

Computed tomography (CT) or magnetic resonance imaging (MRI) can be used to determine the type of stroke.

• If an ischaemic stroke is diagnosed, the interrupted blood supply to the affected area of the brain must be restored – for example, with a drug that dissolves blood clots. This process is called thrombolysis. Another treatment method is thrombectomy: a thin wire (catheter) is pushed into the brain to free the sealed blood vessel from the blood clot.
• In the event of a haemorrhagic stroke, it is important to prevent the bleeding from continuing and damaging other parts of the brain. A perforation or opening in the skull may be required to relieve the brain of excess pressure.