Seizures Resulting From Brain Tumors

A seizure is often the earliest sign of this diagnosis

Not all people with a brain tumor experience seizures. But for those who do, a seizure is often the first symptom of the disease—and what jump-starts the process that leads to tumor diagnosis. The type of brain tumor and its location factor into why some are more vulnerable to experiencing related seizures than others.

MRI scanning procedure.
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Seizures can be frequent and continue throughout treatment for a brain tumor, which can, among other things, comprise one's independence and overall quality of life. In some cases, seizures can pose additional—and significant—health dangers.

Seizures are often the first clinical sign of a brain tumor. Headaches are common with brain tumors, but studies show that it is actually a seizure or other neurological symptom that usually appears first.

How Brain Tumors Cause Seizures

When sudden, abnormal electrical impulse activity in the brain occurs, the result is a seizure.

Tumor-related seizures happen because of the excessive firing of the neurons in and around the tumor. While we don't know why certain tumors cause seizures, some factors might include the location, the type of tumor, genetic factors, and the integrity of the blood-brain barrier.

The frequency of seizures can depend on whether a brain tumor is primary or metastatic. Seizures are also more common in people with low-grade gliomas (the most common type of brain tumor in adults) than in high-grade types. Where the tumor is located is another major factor. In general, brain tumors close to the brain's surface are more likely to cause seizures.

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Types of Brain Tumors and Seizures

Various characteristics of brain tumors can affect seizure type and frequency. One of these characteristics is the type of brain tumor it is. The types of tumors, with their seizure incidences, include:

  • Neurogliomas and gangliogliomas: 80% to 100%
  • Oligodendrogliomas: 70% to 90%
  • Diffuse low-grade gliomas: 60% to 85%
  • Glioblastomas (GBMs): 40% present with epilepsy, and 20% develop seizures later

Seizures are more common in low-grade (more benign tumors). They are also often a positive prognostic factor—although reappearance or worsening of seizures is not.

Recognizing a Brain Tumor-Related Seizure

A brain tumor-related seizure can cause different symptoms for each person. Generally speaking, a seizure can cause physical changes such as:

  • Twitching and convulsions
  • Staring
  • Momentary loss of bowel control and incontinence
  • Loss of consciousness

Other symptoms of a brain-tumor related seizure can include:

  • Intense emotions
  • Numbing or tingling sensations
  • Strange smells or tastes
  • Muscle stiffness or twitching
  • Hallucinations
  • Wandering around
  • Smacking lips or chewing on them
  • Trouble speaking or understanding words
  • Crying out or laughing uncontrollably
  • The feeling of déjà vu

The severity of brain tumor symptoms is not related to how large a tumor is. Rather, location, tumor type, and grade are key factors in what a person experiences.

This is especially true when it comes to seizures. Someone with a tumor in one part of the brain may experience a different type of seizure (and related symptoms) than someone who has a tumor in another location.

Partial seizures (i.e., those that affect only part of the brain) without loss of consciousness tend to be most common in cases where seizures persist.

Seizures are very serious and should never be ignored or left unreported to a physician. If you suspect that you may have had a seizure and are uncertain, report it to your healthcare provider immediately.

Treating Brain Tumor-Related Seizures

Whether a person with a brain tumor has had one or 100 seizure episodes, controlling and preventing seizure activity is an essential part of their treatment.

In most cases, the seizures themselves do not pose a great health risk (unless they last for several minutes or more). Environmental hazards are of greatest concern.


Tumor-related seizures may be controlled with anticonvulsants or antiepileptic medications. Due to the high rate of seizure activity among people with some types of brain tumors, the use of these types of drugs is typically standard. Commonly prescribed medications include:

But not everyone requires medication to prevent or control seizures—only patients who meet certain criteria. And still, for many who fit the criteria, seizures can be resistant to medication.

Treating the tumor itself by reducing its size or removing it may be a more effective (and sometimes permanent) solution.


Not everyone who has a brain tumor has seizures, but sometimes seizures can be one of the first signs of a brain tumor. The seizures that occur can vary in intensity, frequency, and characteristics, depending on the type of brain tumor and its location, among other things.

Treating, managing, and working to prevent seizures is a cornerstone of treatment. This can be done through medications or by surgery. You and your healthcare team can work together to find a treatment plan that is best for you, given the course of your disease, symptoms, and prognosis.

A Word From VeryWell

Seizures don't always look like you think they might. If you notice any abnormal symptoms going on, see your healthcare provider. They can examine you and assess you for seizures. Living with a brain tumor can feel uncertain, but your treatment team can be a source of information, reassurance, and connection.

Frequently Asked Questions

  • What types of brain tumors cause seizures?

    A variety of brain tumors can cause seizures, including neurogliomas, gangliogliomas, oligodendrogliomas, and glioblastomas.

  • Can brain tumor-related seizures go away over time?

    They typically don't go away over time, but they may be able to be managed through medication or surgery.

  • What tests are done to diagnose brain tumor-related seizures?

    Often times the seizure is the first symptom, and in order to find out why the seizures are occurring, imaging tests are done like a CT scan or MRI.

Originally written by Lisa Fayed
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9 Sources
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