Generalized tonic-clonic seizure

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Central nervous system

Generalized tonic-clonic seizure

Alternative Names:

Seizure - tonic-clonic; Seizure - grand mal; Grand mal seizure; Seizure - generalized
Symptoms:

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Many patients have an aura (sensory warning sign) preceding the seizure. This can include a visual, taste, smell, sensory, or other hallucination or dizziness.

The seizure itself involves:

loss of consciousness or fainting, usually lasting between 30 seconds and five minutes
general muscle contraction and rigidity (tonic posture), usually lasting 15 to 20 seconds
violent rhythmic muscle contraction and relaxation (clonic movement), usually lasting for one to two minutes
biting the cheek or tongue, clenched teeth or jaw
incontinence (loss of urine or stool control)
stopped breathing or difficulty breathing during seizure
blue skin color

Almost all people experience loss of consciousness, and most people experience both tonic and clonic muscle activity.

After the seizure:

the person usually begins breathing normally when the seizure is over
arousable but sleepy for one hour or longer
loss of memory (amnesia) regarding events surrounding the seizure episode
headache
drowsiness
confusion, temporary and mild
may be weak for 24-48 hours following seizure (Todd's paralysis)

Signs and tests:

Diagnosis of a grand mal seizure is based on the symptoms and excluding other medical problems that can look like a seizure (such as heart arrythmia). A neuromuscular examination may or may not reveal neurologic deficits (decreases in brain functions) when the person is not actively having seizures.

An EEG may show characteristic changes and in some cases may show the focus (location of the cause of the seizure). An EEG can be normal in between seizures and a normal EEG does not rule out a seizure disorder.

Tests for the cause may include various blood tests (depending on the suspected cause), including: