Epilepsy is a brain disease characterized by recurrent seizures caused by abnormal electrical activity in the brain. Around 50 million people worldwide live with it, making it one of the most common neurological conditions on the planet. Roughly 4 to 10 out of every 1,000 people have active epilepsy at any given time.
What Happens in the Brain During a Seizure
Your brain cells communicate through a careful balance of electrical and chemical signals. Some signals tell neurons to fire (excitatory), while others tell them to quiet down (inhibitory). In epilepsy, that balance breaks down. The brain’s main excitatory chemical becomes too active, the main inhibitory chemical becomes too weak, or both happen at once. The result is a burst of uncontrolled electrical activity that disrupts normal brain function.
Ion channels, the tiny gates on brain cells that control the flow of charged particles in and out, also play a role. When these gates malfunction, neurons can get stuck in an overexcited state, firing repeatedly when they shouldn’t. During a seizure, potassium levels outside brain cells jump from a normal 3 to as high as 12 to 15 units, which pushes large groups of neurons into a state of sustained firing. This is why seizures can affect movement, sensation, emotions, or consciousness depending on which part of the brain is involved.
Types of Seizures
Seizures fall into a few broad categories based on where they start in the brain and how far they spread.
- Focal seizures begin in one specific area of the brain. They might cause a strange taste or smell, a wave of fear, twitching in one hand, or a blank stare with repetitive movements like lip smacking. You may or may not lose consciousness.
- Generalized seizures involve both sides of the brain from the start. The most dramatic type is the tonic-clonic seizure (formerly called grand mal), where the body stiffens and then jerks rhythmically. Other generalized seizures include absence seizures, which look like brief staring spells lasting only a few seconds.
- Unknown onset seizures are those where the starting point can’t be determined, often because no one witnessed the beginning.
Seizures are now described by their full sequence of signs and symptoms rather than just the first thing that happens. Doctors also assess whether consciousness was affected, meaning both your awareness and your ability to respond.
What Causes Epilepsy
Epilepsy has many possible causes, and in a significant number of cases no clear cause is ever found. When a cause can be identified, it typically falls into one of several categories: genetic mutations that affect how brain cells function, structural problems in the brain (such as tumors, malformations, or damage from a stroke or head injury), infections that scar or inflame brain tissue, metabolic disorders, or immune conditions where the body attacks its own brain cells.
Some forms of epilepsy run in families. Specific gene mutations affecting sodium and potassium channels on brain cells are well-documented causes, particularly in severe childhood epilepsies like Dravet syndrome. Other cases develop after a brain injury, and the first seizure may not appear until months or years after the original damage occurred.
How Epilepsy Is Diagnosed
A single seizure does not necessarily mean you have epilepsy. The formal diagnosis requires at least two unprovoked seizures occurring more than 24 hours apart. You can also be diagnosed after just one seizure if your doctor determines the risk of another seizure within the next 10 years is 60% or higher, which is often the case when brain imaging or other tests reveal an underlying cause.
The electroencephalogram (EEG) is the primary tool for detecting abnormal electrical patterns in the brain. It can help identify the type and location of seizure activity. MRI is the preferred imaging method because it can reveal structural problems like scar tissue, tumors, or developmental abnormalities. When read by specialists using dedicated epilepsy protocols, MRI detects subtle brain lesions in up to 91% of cases with drug-resistant epilepsy. Standard MRI readings without that specialized approach catch only about 39%.
If someone has a first-ever seizure, an emergency CT scan is usually done first to rule out urgent problems like bleeding in the brain, followed by a more thorough workup later.
Treatment Options
Anti-seizure medications are the first line of treatment and work well for the majority of people. These drugs come in two general groups. Broad-spectrum medications treat a wide range of seizure types and are often prescribed first when the seizure type isn’t entirely clear. Narrow-spectrum medications target specific seizure types, particularly focal seizures. Finding the right medication and dose can take time, and some people need to try more than one before achieving good seizure control.
For people whose seizures don’t respond to medication (roughly one-third of all epilepsy patients), other options exist. Surgery to remove the area of brain tissue causing seizures is considered the best option when it’s feasible, though about half of surgical patients still experience some seizures afterward. Surgery isn’t always possible, particularly when seizures originate near areas of the brain that control language, movement, or vision, or when multiple areas are involved.
The ketogenic diet, a high-fat, very low-carbohydrate eating plan, is recommended for children who haven’t responded to two or more medications. It works by shifting the brain’s energy source from glucose to compounds called ketone bodies, which appear to boost the brain’s inhibitory signals and reduce seizure activity. Vagus nerve stimulation is another option, where a small device implanted in the chest sends regular electrical pulses to a nerve in the neck. It’s approved for people aged 4 and older with drug-resistant focal seizures.
Living With Epilepsy
Epilepsy is considered “resolved” if you’ve been seizure-free for 10 years and off medication for at least the last 5. Some childhood epilepsy syndromes resolve naturally once a child passes a certain age.
One serious risk that people with epilepsy should know about is sudden unexpected death in epilepsy, or SUDEP. This is rare but represents the leading cause of epilepsy-related death. The single strongest risk factor is poorly controlled tonic-clonic seizures. Even having just one or two per year increases the risk fivefold compared to people free of these seizures. Having three or more per year raises it fifteenfold. Nighttime seizures, epilepsy lasting longer than 15 years, and certain genetic epilepsy syndromes also increase risk. The most effective way to reduce SUDEP risk is keeping seizures as well controlled as possible.
How to Help Someone Having a Seizure
If you see someone having a tonic-clonic seizure (stiffening and jerking), ease them to the ground if they’re falling, clear away nearby objects, and place something soft under their head. Gently roll them onto their side with their mouth pointing toward the ground to keep the airway clear. Loosen anything tight around the neck and remove their glasses.
Time the seizure. If it lasts longer than 5 minutes, call 911.
Do not hold the person down, put anything in their mouth, attempt mouth-to-mouth breathing, or offer food or water until they are fully alert. Restraining someone during a seizure can cause injury to both of you, and placing objects in the mouth can damage teeth or the jaw. Most people begin breathing normally on their own once the seizure stops.