Epilepsy (seizures) and brain tumours

Epileptic seizures are the most common first symptom that leads to a brain tumour diagnosis in adults. It can also develop during the course of the illness, with around 60% of brain tumours patients experiencing a seizure at least once. It is not fully understood why brain tumours can cause epilepsy.

What is epilepsy?

Epilepsy is defined as the tendency to have repeated seizures, so it is usually only diagnosed after you have had more than one seizure. You are more likely to develop epilepsy if you have a slow growing, low grade tumour, but can also develop epilepsy if you have a high grade tumour. In this case, your tumour is likely to be smaller than high grade tumours not associated with epilepsy.

What is a seizure?

A seizure is a short episode of symptoms caused when there is a burst of abnormal electrical activity in the brain that disturbs the way the brain normally works, 'mixing up' the messages. There are many different types of seizures, and they can range from 'feeling a bit strange' or 'absent' to convulsive seizures, twitching of limbs and even loss of consciousness. They are sometimes called 'fits'.

In brain tumour patients, seizures may be related to cells around the tumour that have developed abnormally. Or they may be due to an imbalance of chemicals in the brain caused by the tumour. Both of these factors can interfere with the normal electrical activity in the brain.

Types of seizures

Seizures are normally grouped into two categories, depending on how much of the brain is affected.

Focal (or partial) seizures

These are where only part of the brain is affected. These are the usual types of seizure associated with brain tumours. There are two types of focal seizure.

Simple focal seizure:

  • only a small part of one of the lobes of the brain is affected
  • you will be conscious and normally know what is happening and remember afterwards
  • symptoms that develop will depend on which lobe the seizure happens in (more information can be found in our fact sheet), but during the seizure, you may feel 'strange' and not be able to describe the feeling afterwards. This can be frustrating or upsetting

Complex focal seizure:

  • a larger part of one hemisphere (side) of the brain is affected
  • your consciousness will be affected, so you may be confused, not aware of what you are doing and you are unlikely to remember what happens afterwards
  • you may not be able to fully understand people, or be able to respond to them
  • if you are spoken to loudly, you may think that the person is being aggressive
  • you may wander around or make strange/repetitive movements or sounds
  • after a complex focal, you may still feel confused, making it difficult to tell when the seizure has ended

Generalised seizures

These are seizures that begin in both sides of the brain at the same time. There are six main types of generalised seizure and most types result in the person becoming unconscious, even only for a few seconds and they are unlikely to remember what happened.

Generalised seizures are rarely associated with brain tumours, but some focal seizures can become generalised if they spread to both sides of the brain. This is called a secondary generalised seizure and is often a tonic-clonic type of seizure.

Tonic-clonic seizures (sometimes called grand-mal):

  • initally you will become unconscious
  • your body will become stiff, so you may fall, usually backwards
  • you may cry out or bite your tongue or cheek
  • your muscles will jerk (convulse)
  • your breathing might become more difficult or noisy
  • your skin may change colour - either very pale or may blush
  • you may lose control of your bladder (wet yourself)
  • they normally last 1-3 minutes

Your seizures may not be exactly as one of the types described, but they will usually last the same time and follow the same pattern each time they happen. For some people, however, their seizures do not follow a pattern nor last the same time.

Status epilepticus

Occasionally, seizures may not stop, or one seizure follows another without any recovery in betwen. If this goes on for 30 minutes or more it is called 'status epilepticus' or 'status'. This is uncommon, but potentially serious, and requires hospital treatment.

If a seizure continues for more than 5 minutes or repeated seizures occur without recovery in between, emergency (rescue) medication should be given and/or an ambulance should be called. (Do NOT wait for 30 minutes).

Why do brain tumours cause epilepsy?

Although epilepsy is more likely in low grade tumours and in tumours in the cortex, the exact reasons why these brain tumours can cause epilepsy are not fully understood. For example, it is thought that epileptic seizures in patients with brain tumours do not start in the tumours themselves, but from the areas in the brain next to the tumour.

Cortical dysplasia

Areas around some types of brain tumours are characterised by brain cells that develop abnormally which is known as cortical dysplasia. The abnormal cells fire more frequently, causing uncontrolled, disorganised electrical activity in the brain (hyperexcitability), which can cause seizures.

It is not clear whether cortical dysplasia plays a role in brain tumour-related epilepsy, as complete removal of the tumour often results in seizure freedom, and secondly because cortical dysplasia is not present in all tumour types that are associated with seizures.

Neurotransmitters and signalling pathways

There has been research suggesting that certain 'neurotransmitters' and the pathways down which they send their signals may be involved. The brain consists of over 100 billion nerve cells that communicate with one another by releasing chemicals (neurotransmitters) that excite and inhibit the nerve cells. An imbalance between some of these neurotransmitters can lead to too many nerve cells firing, resulting in the 'electrical storm' that is a seizure.

The presence of a tumour can cause changes to the structure or the chemicals of the cells, both within the tumour and the tissue surrounding it, thereby affecting the electrical activity of the brain.

It is important to know that an increase in the frequency of your seizures does not necessarily mean that your tumour has returned or is re-growing.

Available treatments

Treatment of seizures in people with a brain tumour can be particularly complex and difficult due to the additional effects that having a brain tumour causes. The variety of tumours (type, location and grade), tumour effects and treatments all interact with the variety of seizure types. As a result, some treatments for epilepsy are not suitable for you, or you may have to try several treatments before you find the one that is best for you.

Anti-epileptic drugs (AEDs)

AEDs cannot cure epilepsy, but they are a type of medicine that can help to prevent the occurrence of episodes. Some people with brain tumours find their epilepsy does not respond so well to drugs.


Surgery can reduce or stop the occurrence of episodes completely for a very high proportion of people suffering from epilepsy (with or without brain tumours). However, the presence of a brain tumour makes things more complicated, and surgery might not be the most appropriate treatment option.

Other treatments and complementary therapies

Other treatments, though used in the treatment of non-brain tumour related epilepsy, are not suitable or are rarely used for brain tumour related epilepsy. In some cases, such as the ketogenic diet this is because whether they are effective is still the subject of scientific research.

Identifying the triggers

Seizures often have particular triggers (such as lack of sleep, stress or alcohol). Identifying them allows people to manage their condition by avoiding those triggers as much as possible.

Living with epilepsy

Being told you have epilepsy as well as a brain tumour, can affect people in different ways – some people are relieved that they know what is causing some of their symptoms and can now have treatment; others find it quite hard. This is quite normal.

Talk to your health team or to our Support & Info Line – they can provide practical and emotional support.


The DVLA (Driver Vehicle Licensing Agency) requires people with a brain tumour or epilepsy diagnosis to give up their license. How long it will be until you are able to reapply for you license depends on:

  • your type of tumour
  • where it is in the brain
  • your symptoms
  • the treatment you had
  • whether you have any residual impairment likely to affect safe driving
  • the time since your last seizure
  • the type of seizures you have/had
  • the risk of further symptoms

If you have not yet given up your license, or you have had your license returned after brain tumour treatment, you must stop driving and tell the DVLA if you have a seizure - of any type. This is a legal requirement and you will have to surrender your driving license.


As brain tumour-related epilepsy is often difficult to control, safety may be an issue depending on the type of seizure you have. There are lots of things you can do to make your home safer in case you fall when having a seizure, such as choosing cushioned flooring and using protective covers on sharp edges. You may also find it useful to have an alarm that can alert family or friends, these include seizure alarms, fall call alarms and even a safety pillow if you have asleep seizures. Some people also choose to carry a medical ID card, on which you can give information about your seizures, medication and how you like to be helped.

Information for carers - first aid

If you are a partner, family member or friend of someone recently diagnosed with epilepsy due to a brain tumour, you may find yourself in the role of a carer, particularly if their seizures are unpredictable or more severe. It is important to know what to do to keep them safe when they have a seizure. We have plenty of advice on our epilepsy fact sheet which you can download below.

Page last reviewed: 01/2015

Next review date: 01/2018

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