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Seizures in adults

Seizures are the most common first (onset) symptom that lead to a brain tumour diagnosis in adults. However, brain tumours are rare and seizures can occur for a number of reasons, so if you have a seizure, it does not necessarily mean you have a brain tumour. Sometimes seizures are a one-off

How do I know if a seizure is a symptom of a brain tumour?

All seizures should be checked out by your GP or A&E doctors as they could be due to a serious condition including a brain tumour.

When people hear the term seizure, they often think of convulsive seizures. This is where the person loses consciousness, their body goes stiff and they fall to the floor with their limbs jerking. However, this type (known as a tonic-clonic seizure) is rarely associated with brain tumours.

There are many other types of seizure. The type most commonly associated with brain tumours are called focal (or partial) seizures.

Focal seizures affect only one part of the brain and can affect your movement and/or your level of consciousness or awareness.

The symptoms you have will be different according to where the seizure starts in the brain.

The following are examples of what can happen – you may experience something different.

Symptoms of a focal seizure include:

A small part of one side of the brain is affected. You’ll remember the seizure afterwards, even if you can’t describe it. Symptoms include:

  • feeling a bit strange or absent (spaced out). You may not even notice this sort of seizure yourself – it may be recognised by others around you 
  • intense feeling of emotion
  • unusual smell or taste
  • feeling of ‘déjà vu’ (I’ve been here or done this before) or ‘jamais vu’ (familiar things seem new)
  • rising feeling in the stomach, like you may get on a fairground ride
  • muscle stiffness or twitching that can spread from the hand or foot and may affect half of the body
  • feeling of not being able to speak despite being fully conscious
  • numbness or tingling
  • burning sensation
  • feeling that an arm or leg is bigger or smaller than it is
  • visual disturbances, such as coloured or flashing lights
  • hallucinations (seeing something that isn’t there).

A larger part of one side of the brain is affected. Your consciousness is affected – you may be confused, unaware of what you’re doing, and unlikely to remember what happened afterwards. Symptoms include:

  • you may not fully understand people or be able to respond to them, even though you can hear them
  • if spoken loudly to, you may think the other person is being aggressive
  • wandering around in a confused manner
  • language problems, such as comprehension
  • making strange or repetitive movements or sounds (called ‘automatisms’)
  • visual disturbances, such as coloured or flashing lights
  • hallucinations (seeing something that isn’t there).

Some of these may start as a focal aware seizure. They can last from around 15 seconds to 2-3 minutes. After this type you may still feel confused, making it difficult to tell when the seizure has ended. This is called post-ictal confusion. You may also feel tired and need to rest.

What should I do if I think I’ve had, or someone else is having, a seizure?

All seizures should be checked out by your GP or, depending on the severity, an A&E doctor, to find out the underlying cause.
The symptoms listed above are examples of the type of seizures normally associated with brain tumours. However, having these symptoms does not mean you have a brain tumour. 

It is possible, though rare, for brain tumours to cause other types of seizure, such as the tonic-clonic (convulsive) type seizure.

  • Track your seizures through BRIAN’s quality of life tracker, noting when they are worse or better, any patterns that you see or any changes
  • All seizures should be checked by your GP, or depending on the severity, an A&E doctor. Make sure you talk to the relevant medical professional
  • People often experience more than one symptom before a diagnosis, so make sure you understand what other symptoms a brain tumour can cause
  • Book an appointment with your GP for a check up, and keep a note of any questions that you want to ask
  • Take a look at our page about talking to your doctor for some ideas of what to ask and what to expect.

I think I have a brain tumour, what should I do?

Brain tumours are rare, however, if you’re worried and a symptom persists or if you have more than one symptom of a brain tumour then:

  • Talk to your doctor
    GP appointments are usually quite short, so make sure you find out how to best prepare for your appointment.
  • Get an eye test
    If your symptoms are limited to changes in vision and/or headaches, get your eyes tested by an optician before seeing your GP.
  • Go to A&E
    If the symptoms are sudden or severe, you should go to your emergency department or call 999.

Should I speak to a doctor during the coronavirus pandemic?

We understand you may feel worried about seeking help from your GP during the coronavirus pandemic – but please don’t delay speaking to a healthcare professional.

The NHS and your GP are still here for you and have made changes that make it easier to safely speak to a healthcare professional and get medical help if you need it.

It’s more important than ever for you to prepare for your appointments by understanding what might happen during the appointment and what questions you want to ask.

More information

Symptoms of a brain tumour in adults – PDF

Find out more about the symptoms of a brain tumour in adults in the full fact sheet.

Check the signs and symptoms of a brain tumour

Know the Signs and Symptoms

Although brain tumours are rare, if you or a loved one are experiencing two or more of the signs and symptoms it’s important that you speak to your doctor to rule out a brain tumour.

Check the signs and symptoms of a brain tumour

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By taking part in our Improving Brain Tumour Care surveys and sharing your experiences, you can help us improve treatment and care for everyone affected by a brain tumour.