Seizures: classification, causes, risk factors, symptoms, and prevention
What is a seizure?
Seizures or the convulsion can be defined as an abnormal and synchronous electrical activity of the brain that manifests a characteristic set of symptoms. If a person experiences two or more unprovoked seizures 24 hours apart he is considered to be an epileptic patient. This disease carries significant morbidity and fear among the general population.
Classification of seizures
The convulsions are primarily classified as generalized onset or focal onset. In generalized seizures, abnormal electrical activity occurs involving the entire cerebrum. Therefore, the patient experiences abnormal movements of all four limbs and the body. The patient completely loses consciousness during generalized seizures.
In focal seizures, abnormal electrical activity originates from one focus of the brain. Therefore, only the corresponding part of the body shows abnormal movements. The patient’s consciousness may be normal, impaired, or lost. On some occasions, the focal electrical activity may progress to involve the entire cerebrum. These patients initially experience focal symptoms, but soon develop generalized symptoms. This is called a focal onset with secondary generalization.
Febrile seizures are a specific entity of seizures that occur in children in-between the age group of 6 months to 6 years.
If a convulsion lasts more than 30 minutes or if a person experiences two or more seizures without gaining consciousness during 30 minutes of time, it’s called a “status epilepticus”.
According to the abnormal body movements seen during a seizure, both generalized and focal seizures are further classified as,
- Tonic – Abnormal rigidity of the limbs
- Clonic – Abnormal, repetitive, jerky movements
- Tonic-clonic – Tonic phase followed up by tonic phase
- Atonic – Sudden loss of muscle power
- Absence/ petit-mal seizures – Excessive blinking of the eyes and episodes of starring. No abnormal movements of the body
Causes and Risk factors
Most of the seizure-like events are truly not seizures. Many other pathologies of the body may mimic a seizure.
- Low blood sugar
- Cardiac arrhythmias
- Electrolyte imbalances are notorious to cause seizure-like symptoms.
The true causes and risk factors are
- Having epilepsy is the most significant risk factor
- Head injury
- Infections like meningitis and encephalitis
- Fever, especially in children – Fever associated seizures are called febrile seizures
- Certain drugs
- Excessive alcohol intake and alcohol withdrawal
- Lack of sleep, stress, and exposure to sunlight in those who are having epilepsy
- Brain lesions are strongly suspected in a 1st ever seizure occurring in an otherwise healthy adult (over the age of 20 years)
- Congenital abnormality in the brain (e.g. – cerebral palsy)
Symptoms of seizures
The convulsions are characterized by abnormal, jerky, convulsive movements of the limbs. However, it can happen even without single muscle contraction. The following are seen commonly features in seizures.
- Automatism – Abnormal, repetitive and stereotypic movements like lip-smacking and chewing
- Starring episodes are characteristic of absence seizures
- Frothing from the mouth
- Eyes rolling upwards
- Urinary and fecal incontinence
- Bluish discoloration of the extremities
Some people who have had convulsions explain about an aura that preceded the seizure. These are called epileptic auras. The auras differ according to the focus of the brain where the abnormal electrical discharge is happening. Common auras that people describe are,
- Smell changes
- Auditory and visual hallucinations
- Abdominal sensations
- Deja vu – Sensation of familiarity of a new surrounding
- Jamais vu – Sensation of unfamiliarity of a known surrounding
Following a seizure, the person may not recover his awareness completely for a certain period of time (even if he regains consciousness). Usually, this period (post-ictal period) lasts about 10-20 minutes. The following features are common in the post-ictal period.
- Deep sleep
- Abnormal behavior (e.g. – Undressing, running)
Complications of seizures
Complications of a seizure can be attributed to the effects of the seizure itself and also to the injuries that the patient sustains during an episode.
- Recurrent convulsions may cause brain damage, especially if it’s lasting more than 5 minutes.
- It may affect the day-to-day activities of the person and may hinder the education of children.
- During the episodes, the person may sustain head injuries that may further aggravate the condition.
- The convulsion that occurs during driving or swimming may even kill the person.
- The convulsion that occurs during a pregnancy has an abortive effect on the developing fetus.
Treatment and medications
1st ever seizure occurring in an otherwise healthy person is usually not treated. If the person experiences another seizure or has a high risk to have multiple convulsions, medical treatment can be started. The mainstay of treatment is anticonvulsants. The commonly given anticonvulsants are sodium valproate, diazepam, lamotrigine, etc. However, over-the-counter medication for convulsion or epilepsy should not be done at any cost. Please take medications only after consulting a health-care professional, ideally a neurologist.
If a seizure is lasting more than 5 minutes, it’s considered a potential status epilepticus. Therefore, immediate admission to a hospital and prompt medical treatment is needed.
How to prevent recurrent seizures
If you are an epileptic patient,
- Do not skip the meals
- Have enough sleep daily
- Adhere to the anticonvulsant drug regime
- Reduce stress