Can High Blood Pressure Cause Seizures?

Did you know that approximately 35% of the global population has high blood pressure, also known as hypertension? This number is increasing due to the growing issue of people following unhealthy lifestyles and diets. This is worrying, as high blood pressure can cause a lot of severe health issues, such as cardiovascular diseases and heart attacks. 

It has also been suggested that having high blood pressure may increase your risk for seizures. Read on to find out about what seizures are, how blood pressure relates to seizures, and how you can prevent high blood pressure and therefore seizures.

What Is High Blood Pressure?

As blood gets transported through the blood vessels, it pushes on the blood vessel wall and exerts blood pressure. The blood pressure measured in the arteries when blood is pumped out of the heart is known as systolic blood pressure; the blood pressure measured between heartbeats when the heart is filling up is known as diastolic blood pressure. People with a systolic blood pressure of ≥140 mmHg and a diastolic blood pressure of ≥90 mmHg (≥140/90 mmHg in total) have high blood pressure. It is recommended to keep blood pressure in the range of 90/60 mmHg to 120/80 mmHg. 

Causes

Our body can temporarily increase our blood pressure when we face stressful or dangerous situations. This is due to our sympathetic nervous system becoming stimulated. The sympathetic nervous system is made up of a network of nerves that regulates our involuntary responses to prepare us for a ‘fight or flight’ situation. For example, our body can momentarily increase blood pressure to help transport blood quicker around the body to meet increased demands.  

However, a chronic increase in blood pressure (i.e. hypertension) is a threat to health. 

Long-term high blood pressure usually develops gradually and is mainly caused by an unhealthy lifestyle. Some specific causes of high blood pressure include:

Unhealthy diet 

About ⅓ of high blood pressure cases are caused by excess salt intake. Consistently eating foods with high salt contents (>5 g/day) can cause blood vessels to stiffen in the long term and promote high blood pressure.² Recent theories propose that too much salt causes blood vessels to not be able to dilate as usual in response to excess salt. This results in higher resistance to blood that passes through, causing high blood pressure.¹ High-fat and high-cholesterol foods promote the formation of deposits in the blood vessels, which can reduce the diameter of blood vessels, also causing high blood pressure.  

Lack of physical activity

Exercise is important in preventing the stiffening of blood vessels and inflammation which contribute to high blood pressure.³ 

Underlying health conditions

Conditions such as diabetes, kidney diseases, hormone imbalance and lupus can cause high blood pressure. 

Symptoms

Hypertension does not usually cause observable symptoms, which is why many people do not realise they have high blood pressure until it is measured. 

However, some people may experience the following symptoms when their blood pressure is very high: 

• Breathlessness
• Headaches
• Blurred vision
• Nosebleeds
• Irregular heartbeat

If you are experiencing these symptoms, you should visit your GP as soon as possible because having very high blood pressure can be dangerous.

What Are Seizures

To keep us functioning normally, the neurons in our brains have to communicate properly with each other by generating electrical and chemical signals. When there is a sudden, uncontrolled bout of abnormal electrical activities in a group of neurons, it can disrupt the normal functioning of the brain and cause seizures.

Types Of Seizures

Seizures can be broadly separated into 2 categories:

Provoked seizures

These are seizures triggered by a physical cause, such as:⁴

• Withdrawal syndrome (from drugs or alcohol)
• Head or brain injuries
• Infections
• Stroke
• Fever
• Toxic effects of drugs or poison 

Unprovoked seizures

These seizures are not provoked by any apparent causes. Epilepsy is a neurological disorder in which a person has more than two unprovoked seizures.

Epileptic seizures can be further categorised according to how they started:

Generalised seizures

Generalised seizures happen when abnormal electrical activities affect both hemispheres. 

Focal/Partial seizures 

Focal or Partial seizures are seizures that begin in one area of the brain. If it spreads, it can lead to generalised seizures. 

Unknown onset seizures

When seizures cannot be classified as generalised or focal because their source cannot be determined, these seizures will be classified as unknown onset seizures instead. 

Causes

While provoked seizures have direct causes that lead to their onset, the cause of the abnormal brain electrical activities shown in unprovoked seizures (such as epileptic seizures) is less clear. Genetics, however, has been shown to play a role in increasing the risks of epileptic seizures. For example, family history and certain mutations are associated with epilepsy. 

Psychogenic nonepileptic seizures are another type of seizure, and the cause of these seizures is due to psychological factors, rather than abnormal electrical activities in the brain. These seizures may have similar symptoms to epileptic seizures but are actually due to psychological distress.⁵

Signs And Symptoms

Seizures can cause different symptoms depending on where seizures started in the brain and which brain regions they affect. 

Seizure symptoms can be grouped as motor symptoms and non-motor symptoms. 

Motor symptoms

Motor symptoms affect the muscles and movements of the person having a  seizure. Some people may experience:

• Uncontrollable muscle twitching or limb jerking - clonic, myoclonic, or tonic-clonic seizures
• Stiffening of muscles - tonic seizures
• Loss of muscle control - atonic seizures

Non-motor symptoms

Some seizures affect people’s awareness, consciousness or emotions, but may not cause any motor symptoms. People can experience a sudden loss of awareness, consciousness, or a sudden change in emotions during their seizures.

Treatment 

The treatment of seizures varies according to the type of seizure. Epilepsy patients are usually prescribed antiepileptic drugs to prevent seizures. Patients who do not get better with the antiepileptic drugs may undergo alternative treatments such as surgery, electrical stimulation, and special diets. Cognitive behavioural therapy is recommended for psychogenic nonepileptic seizures.⁶

The Link Between High Blood Pressure And Seizures

In a 1996 study, the researchers found that untreated, severe high blood pressure led to a higher risk for unprovoked seizures during adulthood.⁷ The researchers suggested that it could be due to abnormalities in white matter (a tissue layer in the brain that consists of nerve fibres protected by a fat and protein sheath).⁷ Research done in 2021 also found that high blood pressure is associated with almost twice as high a risk of developing epilepsy in old age.⁸ 

Hypertension increases the risks for cardiovascular diseases, which affect the heart or blood vessels. Stroke is a dangerous condition in which blood vessels in the brain are either blocked or ruptured, causing a lack of oxygen and damage to the affected brain areas. Stroke can cause damage to brain cells and inflammation which increases the risk of epilepsy.⁹ 

Severely high blood pressure may also result in an emergency condition known as hypertensive encephalopathy in some people. Hypertensive encephalopathy happens when high blood pressure forces excess fluids out from the blood vessels in the brain to the surrounding brain areas. These fluids accumulate in the brain and can disturb brain functions, causing confusion, poor vision, and even seizures.¹⁰ 

High blood pressure is also associated with higher risks for psychogenic nonepileptic seizures.¹¹

Tips To Avoid High Blood Pressure 

Food

If you have high blood pressure and have not been taking care of your diet, it is time to change that now. Try these suggestions to help improve your diet and get your blood pressure under control:

• Reduce your salt consumption to <6 g per day (about a spoonful)
• Cut down fat intake
• Limit your alcohol consumption to <2 drinks per day for men and <1 drink per day for women¹²
• Try DASH (Dietary Approaches to Stop Hypertension) diet - this eating plan encourages a balanced diet to help you acquire the nutrients you need to manage your blood pressure level.

Exercise

Aerobic exercises can help to prevent high blood pressure in several ways:^{13, 14}

Prevents your blood vessels from becoming stiff 

Stiff blood vessels do not expand as blood travels through, therefore causing high blood pressure.

Reduces the thickness of the left ventricular wall 

The left ventricle is the heart chamber that pumps blood containing oxygen through your entire body. If the left ventricular wall is thick, the heart pumps the blood out with great force, which then causes high blood pressure.

Prevents obesity

Obesity causes high blood pressure by increasing the activity of the sympathetic nervous system and impairing the salt removal system.¹⁵ 

It is recommended to do daily aerobic exercises for at least 30 - 45 minutes.¹⁴ Some aerobic exercises you can try include:

• Swimming
• Jogging
• Cycling
• Sports 

Vitamins

Some studies have found that vitamins B6, C, and D can help in reducing your blood pressure.^{16, 17} However, this theory is controversial.¹⁸ That is why it is important that you continue to take your blood pressure medication as prescribed by your GP. 

You should obtain sufficient amounts of vitamins C and D, as a deficiency in these vitamins is associated with higher risks of hypertension and cardiovascular diseases. You can obtain these vitamins by eating vitamin-rich foods or taking supplements. Make sure to take these vitamin supplements as advised by your GP, especially if you are taking medication or other supplements.

When To See A Doctor

People within the 18 - 40 age range are recommended to check their blood pressure every 2 years. People who are 40 years and above should check their blood pressure yearly, and can do so at their local GP surgery. 

You should seek medical attention as soon as possible if your blood pressure reading is ≥180/120 mmHg and you have these symptoms: 

• Shortness of breath
• Chest pain
• Nausea
• A severe headache
• Numbness
• Changes in vision 
• Difficulty speaking 

You should also go call the ambulance immediately if you witness:

• Someone having a seizure for the first time. 
• Someone having a  seizure that lasts longer than usual or for longer than 5 minutes.
• Someone having multiple seizures or someone not regaining consciousness. 

Complications

High blood pressure can be dangerous if left untreated. This is because chronic high blood pressure can cause structural changes to the blood vessels and heart and limit the blood flow to some body regions.¹³ This increases the risks for other health conditions, such as heart attack, stroke, and kidney failure.

Summary

High blood pressure is a health risk that causes various conditions, including seizures. Seizures can be categorised into 3 different groups depending on the cause:

• Unprovoked seizures (no provoking cause, e.g. epileptic seizures)
• Provoked seizures (due to a physical cause)
• Psychogenic nonepileptic seizures (due to psychological distress)

High blood pressure increases the risks for both epileptic and psychogenic nonepileptic seizures, as well as provoked seizures due to stroke. You should go to the hospital immediately if you have severely high blood pressure and experience abnormal symptoms, as you may be having a hypertensive emergency.