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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 of seizure (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:

Focal aware seizures

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).

Focal impaired awareness seizures

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’)
    • picking up or fiddling with objects or clothing
    • chewing or lip-smacking movements
    • muttering or saying repeated words that don’t make sense
    • making strange movements or postures, such as cycling or kicking, often at night
    • screaming or crying out loudly or laughing uncontrollably
  • visual disturbances, such as coloured or flashing lights
  • hallucinations (seeing something that isn’t there).

Some of these seizures may start as a focal aware seizure. They can last from around 15 seconds to 2-3 minutes. After this type of seizure, 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 of the seizure, 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.

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

Brain tumours are rare, however, if you're worried, if a symptom persists or if you have more than one of these symptoms then:

  • Talk to your doctor
    GP appointments are usually quite short, 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.