Symptoms:

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

• Loss of consciousness or fainting, usually lasting between 30 seconds and 5 minutes
• General muscle contraction and rigidity (tonic posture), usually lasting 15-20 seconds
• Violent rhythmic muscle contraction and relaxation (clonic movement), usually lasting for 1-2 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 lose consciousness, and most people have both tonic and clonic muscle activity.

After the seizure, the person usually has:

• Normal breathing
• Sleepiness lasts for one hour or longer
• Loss of memory (amnesia) regarding events surrounding the seizure episode
• Headache
• Drowsiness
• Confusion, temporary and mild
• Weakness 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 arrhythmia). 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:

• Complete blood count
• Blood chemistry, blood glucose
• Liver function tests
• Kidney function tests (BUN, creatinine, etc.)
• tests for infectious diseases (depending on the suspected cause)

• Head CT or MRI scan
• Lumbar puncture (spinal tap)

Disorders that may cause symptoms resembling seizures include transient ischemic attacks, rage, or panic attacks.