Seizures

Certain types of cancer and cancer treatments can increase your risk of seizures. This is rare, but it does happen. You, your family, and your caregivers should know the signs and symptoms of a seizure and what to do if you have one.

What is a seizure?

A seizure is a glitch in your nervous system caused by an uncontrollable surge of electrical activity in your brain.

One way to think of this is to imagine a traffic light during a power outage.

Your brain cells (neurons) communicate through electrical signals. These signals work a lot like traffic lights. During a power outage, the electricity going to a traffic light sometimes surges (increases suddenly for a short amount of time).

When this happens, the power surge causes a glitch in the traffic light, creating chaos and confusion. This is similar to what happens to your brain during a seizure.

There are two main types of seizures, depending on where in the brain they occur.

• Focal seizures happen in one specific area or side of the brain.
• Generalized seizures happen in both sides of the brain at the same time.

You might also hear the term epilepsy. Epilepsy is the medical name used if a person has 2 or more seizures at least 24 hours apart without a known cause.

Why do some people with cancer have seizures?

There are several reasons why a person with cancer might have seizures.

• Tumors in the brain or spine
• Brain injuries, including those caused by a stroke, head trauma, lack of oxygen, or brain surgery
• Certain types of chemotherapy, especially when given into the spinal fluid (intrathecal or IT chemo)
• Certain types of immunotherapy, such as checkpoint inhibitors and CAR T-cell therapy.
• Hormone changes due to any cause, especially hormone therapy or when sex hormones are affected
• High fevers and certain infections
• Blood sugar levels that are too high or too low
• Electrolyte levels (such as potassium or sodium) that are too high or too low
• Paraneoplastic syndromes (a group of side effects that develop in some people with cancer; these usually affect the nervous system and sometimes cause seizures)

What are the signs and symptoms of a seizure?

The most common signs and symptoms of a seizure are:

• A blank stare or rolled eyes
• Moaning or mumbling
• Falling or slumping over due to loss of consciousness
• Muscle twitching or jerking (especially arms and legs)
• Sudden loss of bladder or bowel control
• Confusion or memory loss
• Weakness or fatigue

Some people report that they can sense a seizure right before it starts. This is commonly called an aura. People who have auras often describe them as a strange or unusual feeling, emotion, or sensation.

If you see someone having a seizure

There are six important steps you should take if you are with someone when they have a seizure.

1. Check safety first. Make sure the person having the seizure is safe. Remove any sharp objects or hazards that could hurt them. Loosen any clothing around their neck.

2. Position carefully. Gently guide the person to lie down on their side. This helps prevent choking and allows any fluids to drain from their mouth.

3. Don’t restrain. Restraining a person during a seizure increases the chances one or both of you will get hurt. Avoid holding them or trying to control their movements.

4. Watch the clock. Note the time when the seizure starts and ends. Most seizures last a few minutes or less. Seizures lasting more than 5 minutes are known as grand mal seizures and can cause serious problems.

5. Comfort and support. Speak to the person calmly and reassure them. After the seizure ends, they might be confused or afraid.

6. Write it down. Pay attention to what happens during the seizure. Write down any signs or symptoms you notice. Keep this information to give to the person’s health care team.