Tonic-Clonic (Grand Mal) Seizure: Symptoms, Outlook, and More
Tonic seizures and clonic seizures can occur individually from each other. However, as the name suggests, a tonic-clonic seizure is a type of epileptic seizure that starts with a tonic phase, followed by a clonic phase.
Tonic seizure episodes can cause:
- muscle stiffness or tension
- indeliberate noises, like a cry or a groan
- impaired awareness
- accidental biting of the tongue or cheek, which may cause blood in the saliva
Clonic seizures can cause involuntary, uncontrolled muscle contractions. Because of the involuntary movements, clinicians may refer to tonic-clonic seizures as a type of motor seizure.
Tonic-clonic seizure symptoms may affect the whole body.
Additional symptoms of a tonic-clonic seizure include:
- abrupt loss or reduction in consciousness
- general stiffening of the body
- jerking that is regular, rhythmic, or sustained
- bending and relaxing at the joints
- difficulty breathing
- blueness or discoloration of the skin, particularly around the mouth and nails
- loss of control of the bladder or bowel
A tonic-clonic seizure usually lasts 1–3 minutes. The tonic stage possibly may last only seconds.
Tonic-clonic seizures can be recurrent, meaning another seizure may happen again immediately after an initial tonic-clonic seizure or later on.
Some people may experience a seizure aura with a tonic-clonic seizure. Aura refers to unusual symptoms that occur before the tonic phase begins, such as:
- changes in mood
- changes in understanding or thinking
- changes in senses, such as hearing, taste, or smell
- vision changes
Symptoms during recovery
After a tonic-clonic seizure, a person may experience:
- slowly returning awareness and consciousness
- fatigue and sleepiness
- memory impairment or loss
- mood symptoms, such as irritability or depression
Call 911 for severe seizure symptoms
Not all seizures are medical emergencies, but some are. Call 911 or seek emergency medical treatment for any of the following traits with seizures:
- The seizure lasts
5 minutes or more Trusted Source Centers for Disease Control and Prevention (CDC) Governmental authority Go to source.
- It could be the person’s first seizure.
- The person has multiple seizures in a row without recovery.
- The person has difficulty recovering afterward, such as difficulty breathing or regaining consciousness.
- The person was injured before, during, or after the seizure.
- The seizure happened in water, such as while showering or swimming.
- The person has another health condition, such as diabetes or heart disease, or is pregnant.
It is advisable to place anyone having a seizure in the recovery position to
Learn more about first aid during a seizure.
Tonic-clonic seizures can occur on their own or develop as a
Tonic-clonic seizures can happen as provoked seizures. These are not the result of epilepsy but are a symptom of acute illness. Conditions such as infections, stroke, and concussion can provoke tonic-clonic seizures.
Learn more about what can cause provoked seizures.
Epilepsy can cause tonic-clonic seizures. During an epileptic seizure, the brain’s nerve cells send hundreds of uncontrolled electrical signals, which cause the symptoms of epilepsy.
Epilepsy can develop from factors and causes such as:
- genetic factors
- structural differences in the brain
- acquired brain injury or illness, such as infection, stroke, or concussion
Sometimes, the cause of epilepsy is unknown.
If you have epilepsy, certain factors can trigger the onset of a seizure. These triggers can be individual to each person, although examples include:
- illness or fever
- lack of sleep
- hormonal changes
- certain foods
Read more about the causes and triggers of seizures.
A 2019 study suggests that tonic-clonic seizures are more common in people assigned male at birth.
Other risk factors for tonic-clonic seizures can be similar to risk factors for other seizure types, such as:
- family history of epilepsy
- brain injury or illness
- prolonged febrile, fever-induced, seizures
- low birth weight
- use of illegal drugs, or misuse of substances such as alcohol and prescription drugs
- conditions such as:
- high blood pressure
- sleep disorders
- structural differences in the brain
- conditions which affect intellectual or developmental ability
Learn more about reducing your risk of seizures.
According to a
Additional treatments for epilepsy can include:
- antiepileptic drugs
- Epidiolex, an FDA-approved form of cannabidiol
- nerve stimulation, such as:
- vagus nerve stimulation
- deep brain stimulation
- responsive neurostimulation
- brain surgery
- ketogenic diets
- complementary treatments, such as occupational therapy or seizure trigger management
Read more about treatments for epilepsy.
Not everyone who has had a tonic-clonic seizure will have another one in their lifetime. A 2017 study suggests that the likelihood of having another tonic-clonic seizure may be 30–50%.
The outlook with tonic-clonic seizures can vary according to:
- cause of the seizure
- severity and frequency of seizures
- underlying health
- EEG results
- imaging test results, such as from CT or MRI scans
Tonic-clonic seizures and epilepsy can sometimes have significant complications, such as:
- impaired quality of life
- breathing complications, such as pulmonary aspiration
- status epilepticus
- brain damage
- increased risk of:
However, not everyone will experience complications. Additionally, the World Health Organization (WHO) estimates that
For advice about optimizing your treatment and outlook, contact your doctor.
Nancy Hammond, M.D., has reviewed the following questions people also ask about tonic-clonic seizures.
What are the 4 stages of a tonic-clonic seizure?
A tonic-clonic seizure may begin with an aura. However, not all do.
With or without aura, the pre-seizure stage is followed by the two main stages of a tonic-clonic seizure: a tonic phase and then a clonic phase.
Once the seizure ends, this is known as the post-ictal stage.
What is the difference between tonic and clonic seizures?
Tonic seizures and clonic seizures are two different seizure types. Tonic seizures cause muscle stiffness and tension, whereas clonic seizures cause muscle contractions or jerking.
When they occur together, this is known as a tonic-clonic seizure.
Do seizures cause brain damage?
Seizures can sometimes cause brain damage. However, damage is most likely with prolonged seizures or seizures that cause further complications.
Learn more about seizures and brain damage.
Tonic-clonic seizures, previously called grand mal seizures, are a type of epileptic seizure that occurs in two phases. These include a tonic phase, which can cause muscle stiffness, and a clonic phase, which can cause muscle contractions and jerking.
Conditions that cause injury, illness, or structural differences in the brain can lead to tonic-clonic seizures.
Treatment for tonic-clonic seizures can include medication and nerve stimulation. While some possible complications can be serious, treatment can be very effective at reducing seizures and improving quality of life.