What are Tonic-Clonic Seizures? 2025 Complete Guide

Tonic-clonic seizures, formerly known as grand mal seizures, are among the most recognizable types of epileptic seizures.

If you’ve ever witnessed one or are trying to understand what they mean for someone you care about, you’re not alone. In this article, you can find out everything you need to know about tonic-clonic seizures, from recognition to response.

What Are Tonic-Clonic Seizures?

Tonic-clonic seizures are characterized by their distinctive two-phase pattern, but they can actually begin in different ways depending on where the abnormal electrical activity starts in the brain.

The name describes the two distinct phases of the seizure: the tonic phase where muscles become rigid and stiff, followed by the clonic phase where muscles jerk rhythmically.

These seizures can originate in one of two ways in the brain:

1. Generalised Tonic-Clonic Seizure

When the abnormal brain activity begins simultaneously on both sides of the brain, doctors call this a generalised tonic-clonic seizure or generalised onset motor seizure.

2. Focal to Bilateral Tonic-Clonic Seizure

However, some tonic-clonic seizures start in just one area of the brain before spreading to affect both sides. These are known as focal to bilateral tonic-clonic seizures, meaning they begin as a focal seizure but then generalize to involve the entire brain.

These seizures typically last between one and three minutes and can be scary to witness. However, understanding what’s happening during a seizure can help you respond appropriately and provide better support to those who experience them.

Understanding the Two Phases

Tonic-clonic seizures follow a predictable pattern that unfolds in two distinct phases.

1. Tonic Phase

During the tonic phase, which usually lasts 10 to 20 seconds, the person experiences sudden loss of consciousness as their muscles become rigid throughout their body. This stiffening often causes them to fall to the ground if they’re standing, and they may emit a cry or groan as air is forced through their vocal cords. Their breathing may temporarily stop, and their skin might appear blue due to lack of oxygen.

2. Clonic Phase

The clonic phase follows, lasting anywhere from 30 seconds to two minutes. During this time, the person’s arms and legs jerk rhythmically, with these movements gradually slowing down as the seizure progresses. They may lose bladder or bowel control, produce excessive saliva and occasionally bite their tongue.

It’s important to understand that these are normal parts of the seizure process and not signs of additional medical emergencies.

What Causes Tonic-Clonic Seizures?

The underlying causes of tonic-clonic seizures vary considerably from person to person. Epilepsy is the most common cause, where seizures occur due to abnormal electrical activity in the brain. Some people inherit a genetic predisposition to seizures, while others develop them following brain injuries, strokes, brain tumors, or infections like meningitis or encephalitis.

Beyond these primary causes, various factors can trigger seizures in susceptible individuals. Sleep deprivation is one of the most common triggers, as is stress. Other triggers include missing medications, hormonal changes and fever, particularly in children.

Why Do Tonic-Clonic Seizures Occur?

Tonic-clonic seizures occur when there’s a sudden surge of abnormal electrical activity in the brain that disrupts normal brain function. Think of your brain as an electrical system with billions of nerve cells communicating through electrical impulses. When this system becomes overloaded or misfires, it can cause the synchronized electrical storm that creates a seizure.

The brain has natural mechanisms to prevent excessive electrical activity, but when these protective systems fail or become overwhelmed, seizures can occur. This electrical disruption affects the brain’s ability to control muscle movement and consciousness, leading to the characteristic stiffening and jerking movements of tonic-clonic seizures.

Are Tonic-Clonic Seizures Dangerous or Life-Threatening?

While tonic-clonic seizures can appear frightening, most are not immediately life-threatening when they occur as isolated events lasting less than five minutes. However, they do carry certain risks that make proper response and medical management important.

The primary dangers during a tonic-clonic seizure include injury from falling or hitting objects, breathing difficulties during the seizure, and potential complications if the seizure doesn’t stop naturally. Status epilepticus, where seizures last longer than five minutes or occur repeatedly without recovery, is a medical emergency that requires immediate treatment.
Long-term risks depend largely on seizure frequency and control. Well-controlled seizures with proper medical management typically don’t significantly impact life expectancy, while frequent, uncontrolled seizures can pose greater risks over time.

Can Tonic-Clonic Seizures Cause Brain Damage?

The question of whether tonic-clonic seizures cause brain damage is complex and depends on several factors. Brief, infrequent seizures lasting less than five minutes typically don’t cause permanent brain damage in most people. The brain has remarkable resilience and can recover from short periods of abnormal electrical activity.
However, prolonged seizures or status epilepticus can potentially cause brain damage due to the intense metabolic demands placed on brain cells during extended seizure activity. Additionally, very frequent seizures over many years may have cumulative effects, though this varies significantly among individuals.
The key factor is in seizure control. According to the World Health Organisation (WHO), around 70% of people achieve seizure control through medication and lifestyle management. This is why early diagnosis and effective treatment are so important for long-term brain health.

Recognizing the Warning Signs: What to Expect

Many people experience warning signs before a tonic-clonic seizure begins. These warning signs, commonly called auras, are actually focal aware seizures – small seizures where the person remains conscious and aware of their surroundings. During these focal aware seizures, people might experience strange tastes or smells, feelings of déjà vu, sudden fear or anxiety, visual disturbances or headaches. Understanding that auras are themselves a type of seizure helps explain why they can be so distinctive and memorable. These warning signs can help individuals get to a safe place or alert others before the tonic-clonic seizure fully develops.

During the seizure itself, the person falls unconscious as their body becomes rigid and then jerks rhythmically. Their breathing may become irregular, their face might turn blue, and their eyes may roll back. You might notice foaming at the mouth, which occurs due to increased saliva production.
After the seizure ends, the person enters what’s called the postictal period. During this recovery phase, they typically experience confusion and disorientation, extreme tiredness, headache, and muscle soreness. They won’t remember the seizure itself, and their gradual return to normal awareness can take anywhere from minutes to hours.

How to Help Someone Having a Tonic-Clonic Seizure

When you witness someone having a tonic-clonic seizure, your response can make a significant difference in their safety and recovery. The most important thing is to stay calm and time the seizure using your phone or watch.

Keep the person safe by moving any dangerous objects away from them, and cushion their head with something soft like a jacket or pillow. If possible, gently turn them on their side to prevent choking and loosen any tight clothing around their neck. These simple actions can help ensure their airway remains clear and they can breathe more easily.

However, there are several important things you should never do during a seizure.

• Never put anything in the person’s mouth, despite the common myth about swallowing tongues;

• Don’t try to hold them down or stop their movements, as this can cause injury;

• Don’t give them water or food;

• Don’t perform CPR unless they’re not breathing after the seizure completely ends.

You should call emergency services if:

• The seizure lasts longer than 5 minutes;

• If multiple seizures occur without recovery between them;

• If the person is injured during the seizure;

• If their breathing doesn’t return to normal afterward.

Also call for help if the person has diabetes or is pregnant, or if this is their first known seizure.

Treatment and Management Options

Most people with tonic-clonic seizures can achieve seizure control through antiepileptic medications. Common first-line treatments include valproic acid, lamotrigine, and levetiracetam, though finding the most effective medication often requires trying different options under medical supervision.

Beyond medication, lifestyle modifications play a crucial role in seizure management:

• Maintaining a regular sleep schedule is essential, as sleep deprivation is a common trigger.

• Managing stress through relaxation techniques, meditation, or counseling can also help reduce seizure frequency.

• Regular exercise is beneficial, though it should be done with appropriate precautions and medical guidance.

For people whose seizures don’t respond well to medication, advanced treatment options are available. These include vagus nerve stimulation, where a device is implanted to send electrical signals to the brain, specialized diets like the ketogenic diet and in select cases, epilepsy surgery.

Living with Tonic-Clonic Seizures

People with tonic-clonic seizures often face various challenges in their daily lives. Driving restrictions vary by location and depend on seizure control, with most areas requiring a seizure-free period before driving privileges can be restored. 
Social situations and relationships can also be affected, as some people worry about having seizures in public or feel anxious about others’ reactions. Mental health concerns, including depression and anxiety, are common among people with epilepsy and should be addressed as part of the comprehensive care plan.

Supporting Someone with Tonic-Clonic Seizures

Family members can provide invaluable support by learning about the condition and proper first aid procedures. Creating a seizure action plan ensures everyone knows how to respond appropriately. Maintaining a seizure diary helps track patterns and identify potential triggers, while ensuring medication compliance and providing emotional support are equally important.
Teachers and caregivers should understand their student’s or patient’s specific needs and know the appropriate response protocols. Educating other students or colleagues appropriately, maintaining open communication with families, and having emergency contact information readily available are essential steps in creating a supportive environment.

You can download here a seizure action plan template! A seizure action plan should include a description of the typical seizures, specific first aid steps, guidelines for when to call emergency services, emergency contact information, current medications and dosages, as well as healthcare provider details.

Prevention Through Pattern Recognition

One of the most effective ways to gain control over tonic-clonic seizures is by understanding your personal patterns and triggers.

Keeping a detailed seizure diary can help identify personal triggers and patterns. Recording the time and date of seizures, potential triggers like stress or sleep deprivation, detailed descriptions of the seizures, recovery times, and any changes in medication or lifestyle can provide valuable insights for both patients and their healthcare providers.

Effective medication management involves taking medications exactly as prescribed without skipping doses. Side effects should be discussed with healthcare providers, and regular blood tests may be needed to monitor medication levels. It’s crucial never to stop medications suddenly without medical supervision, as this can trigger dangerous seizures.

Lifestyle strategies that support seizure control can be essential, such as maintaining a consistent sleep schedule of seven to nine hours nightly, managing stress through various techniques, staying hydrated, and maintaining regular meal times. Teachers and caregivers should understand their student’s or patient’s specific needs and know the appropriate response protocols. Educating other students or colleagues appropriately, maintaining open communication with families, and having emergency contact information readily available are essential steps in creating a supportive environment.

A seizure action plan should include a description of the person’s typical seizures, specific first aid steps, guidelines for when to call emergency services, emergency contact information, current medications and dosages, and healthcare provider details.

When to Seek Medical Care

Regular follow-up appointments with a neurologist are essential for monitoring seizure control and adjusting treatment as needed. These visits typically involve medication level monitoring, discussing any changes in seizure patterns, and reviewing treatment effectiveness.
Emergency medical attention is necessary if seizures become more frequent or severe, if new types of seizures develop, if medication side effects become problematic, or if status epilepticus occurs, which is when seizures last over 5 minutes or occur repeatedly without recovery between them.

Long-term Outlook and Success Factors

Many people with tonic-clonic seizures can achieve excellent seizure control with appropriate treatment. While the condition requires ongoing management, most individuals can lead fulfilling lives with proper medical care and strong support systems in place.
Success in managing tonic-clonic seizures typically depends on early diagnosis and treatment, consistent medication adherence, having a strong support network, making healthy lifestyle choices, and maintaining regular medical monitoring. Each person’s experience with seizures is unique, making it essential to work closely with qualified healthcare professionals to develop an effective, personalized treatment plan.

Moving Forward with Confidence

Understanding tonic-clonic seizures empowers patients, families, and caregivers to respond appropriately and provide effective support. While these seizures can be dramatic and frightening, proper knowledge, treatment and support systems enable most people to manage their condition successfully.
Whether you’re a patient newly diagnosed with epilepsy, a family member learning to support a loved one, or a caregiver wanting to be better prepared, remember that education and preparation are your most powerful tools.

With proper management and support, many people with tonic-clonic seizures go on to live full, productive lives, pursuing their goals and dreams while effectively managing their condition.
Working with healthcare providers, including neurologists and epilepsy specialists, remains essential for developing and maintaining an effective treatment plan. The field of epilepsy care continues to advance, offering new hope and improved outcomes for people living with seizure disorders.

This information is for educational purposes only and should not replace professional medical advice. Always consult with healthcare providers for personalized medical guidance and treatment recommendations.