Understanding Brain Strokes: Causes And Triggers

A stroke is a life-threatening medical emergency that occurs when there is an issue with blood flow to the brain. This can be due to blocked blood flow or bleeding in the brain. Without a steady supply of blood, brain cells are starved of oxygen and begin to die within minutes, causing permanent brain damage or even death. Prompt recognition of stroke symptoms and immediate medical attention are critical to improving outcomes and preventing long-term disability.

Blocked blood flow to the brain

The middle cerebral artery is the artery most commonly blocked during a stroke. This blockage can lead to a range of symptoms, including sudden numbness or weakness on one side of the face, arm, or leg, difficulty speaking or understanding language, blurred or lost vision, and sudden dizziness or loss of balance. These symptoms can vary depending on the area of the brain affected and can indicate permanent brain damage.

Ischemic strokes can be further classified into three types:

• Thrombosis: Formation of a clot in the brain.
• Embolism: A fragment of a clot formed elsewhere in the body breaks free and travels through the blood vessels until it gets stuck in the brain.
• Lacunar stroke: Small vessel blockage that can occur due to long-term untreated high blood pressure, high cholesterol, or high blood sugar.

The risk factors for ischemic stroke include high blood pressure, heart disease, diabetes, smoking, high cholesterol, excessive alcohol consumption, illegal drug use, abnormal heart rhythm, and cardiac structural abnormalities.

Immediate emergency treatment is critical for surviving an ischemic stroke and minimising brain damage. Treatment options include clot-busting medications, such as thrombolytics, thrombectomy procedures, and supportive treatments like oxygen and intravenous fluids.

Bleeding in the brain

A stroke is a life-threatening medical emergency that occurs when there is an issue with blood flow to the brain. This can be caused by blocked blood vessels or bleeding in the brain. When a stroke occurs due to bleeding in the brain, it is known as a brain haemorrhage or a haemorrhagic stroke.

Brain haemorrhages account for about 13% of all strokes and can be caused by a weakened blood vessel that leaks or suddenly bursts, damaging brain cells by depriving them of oxygen and nutrients. This can be caused by several factors, including head trauma, high blood pressure, aneurysms, blood vessel abnormalities, amyloid angiopathy, blood or bleeding disorders, liver disease, and brain tumours.

There are two main areas of the brain that are affected by haemorrhagic strokes: the area between the brain tissue and the skull, and inside the brain tissue itself. When bleeding occurs inside the skull but outside the brain tissue, it is known as an epidural, subdural, or subarachnoid haemorrhage, depending on the specific location. An epidural haemorrhage occurs between the skull bone and the outermost membrane, called the dura mater. A subdural haemorrhage occurs between the dura mater and the arachnoid membrane, and a subarachnoid haemorrhage occurs between the arachnoid membrane and the pia mater, the delicate inner layer beneath it.

When bleeding occurs inside the brain tissue, it is known as an intracerebral or intraventricular haemorrhage. An intracerebral haemorrhage occurs in the cerebellum or brainstem, while an intraventricular haemorrhage occurs in the ventricles of the brain, the chambers that contain cerebrospinal fluid.

The symptoms of a brain haemorrhage can vary depending on the location and severity of the bleeding. However, common symptoms include sudden severe headaches, sensitivity to light, seizures, weakness in the arms or legs, decreased alertness, changes in vision, tingling or numbness, difficulty speaking or understanding others, difficulty writing or reading, loss of fine motor skills, an abnormal sense of taste, and loss of consciousness. It is important to seek immediate medical attention if any of these symptoms are present, as brain haemorrhages can be life-threatening and early treatment improves the chances of recovery.

High blood pressure

The higher the blood pressure, the greater the risk of stroke. Normal blood pressure is considered to be around 120/80. If your blood pressure is regularly over 140/90, you have high blood pressure. The risk of high blood pressure increases with age, and men are more likely to experience it than women. It is also more common among people with a family history of high blood pressure, those who consume excessive alcohol, and those who eat a high-salt diet.

Managing high blood pressure is critical to reducing the risk of stroke. This can be achieved through medication, treatment, and lifestyle changes such as regular exercise and maintaining a healthy weight.

Blood clots

There are two types of ischemic strokes: cerebral embolism and cerebral thrombosis. A cerebral embolism occurs when a blood clot forms in another part of the body, often the heart or arteries in the upper chest and neck, and then moves through the bloodstream. It continues until it reaches an artery that is too narrow, gets stuck, and stops the blood flow, thus causing a stroke. A cerebral thrombosis occurs when a blood clot develops at the fatty plaque within the blood vessel.

There are several factors that can lead to blood clots causing a stroke. Blood clots can arise from coronary heart disease, atrial fibrillation, heart valve disease, and carotid artery disease. Sickle cell disease, a condition that is more common in African Americans, non-white Hispanic Americans, people from the Mediterranean, the Middle East, and Asia, can also lead to blood clots and cause strokes. In addition, chronic inflammation can contribute to ischemic strokes by damaging blood vessels and contributing to atherosclerosis.

Ischemic strokes are the most common type of stroke, accounting for about 80% of all strokes. They are caused by blocked blood flow to the brain, usually due to a piece of plaque or a blood clot. If the blockage occurs locally in the brain, it is called thrombosis, whereas if the blood clot travels from somewhere else in the body, it is called an embolism.

Recognizing the symptoms of a stroke and seeking immediate medical attention is crucial. Some signs of a stroke include numbness or weakness on one side of the body, trouble speaking or understanding others, confusion, sudden behavioural changes, vision problems, and loss of balance or coordination.

Lifestyle factors

Smoking and Tobacco Use:

Nicotine consumption, whether through smoking or chewing tobacco, is a major risk factor for strokes. It causes an increase in blood pressure and contributes to the formation of fatty buildup in the main neck artery, leading to narrowed arteries. Even exposure to secondhand smoke can elevate the risk.

Alcohol Consumption:

Heavy alcohol use is linked to elevated blood pressure, which is a leading cause of strokes. Alcohol misuse can also increase the chances of a stroke occurring.

Diet and Weight Management:

An unhealthy diet, particularly one high in salt, saturated and trans fats, and cholesterol, can increase the likelihood of a stroke. Maintaining a balanced weight through proper diet and regular exercise is crucial for stroke prevention. Obesity and being overweight are risk factors that can be mitigated by adopting healthier lifestyle choices.

Physical Activity:

Lack of physical activity and a sedentary lifestyle can contribute to an increased risk of strokes. Engaging in daily exercise, such as brisk walking or muscle-strengthening activities, can help lower the odds of experiencing a stroke.

Stress and Mental Health:

Anxiety, depression, and high-stress levels, coupled with limited social connections, may elevate the risk of a stroke. Addressing mental health issues and finding healthy coping mechanisms are important aspects of stroke prevention.

Sleep Patterns:

While getting enough sleep is essential, excessive sleep (more than 9 hours) has been associated with an increased risk of strokes. Maintaining a healthy sleep schedule is beneficial for overall health and can positively impact stroke prevention.

Illegal Drug Use:

The use of illegal drugs, such as cocaine, has been linked to a higher risk of strokes. It is crucial to avoid substance abuse and seek professional help if struggling with addiction.

Frequently asked questions