What is Seizure?

What is Seizure?

Seizure is an alteration in behavior due to abnormal synchronous discharges of neurons in the brain. Seizure symptoms depend on location of discharging neurons. If seizures originate from the neurons close to area controlling motor activity, the patient will experience physical activity such as shaking of a limb during the seizure. Since seizure activity may spread to neighbor areas, one limb shaking may spread to the other limbs and subsequently whole body may convulse. If the seizure activity starts in the area near the sensory control region, the patient may feel pins and needles sensations on one side of body which may spread to other parts depending on the way and pattern the seizure activity spreads

Sometimes patients may feel déjà-vu, jama-vu or different psychic feelings. That means seizure originates in an area close the medial part of temporal lobe. As mentioned seizures can manifest different symptoms depending on the area of origin.

Seizures can occur at any time, often without warning. In most people, seizures are easily controlled with medication; in others, seizures continue despite treatment and may last a lifetime.

What is aura? Does everyone have aura?

Aura is the first sign of seizure. It means the seizure originates from an area which can make the patient feel symptoms before the full blown spell. Auras are usually followed by loss of awareness and sometimes by generalized convulsions. Sometimes auras can stop without any further clinical symptoms.

Not every epilepsy patient has aura prior to seizures. Some patients with auras may end up not having auras in the future. Auras can also change in features with time.

What Kind Of Seizure Do I Have ?

Seizures are classified as partial, generalized tonic clonic, absence, myoclonic, atonic and tonic seizures. Epileptic seizures are classified as follows:

International Classification of Epileptic Seizures

I. Partial seizure

  • Simple partial seizures (consciousness not impaired): Motor, Sensory, Autonomic
  • Complex partial seizures (with impairment of consciousness)
  • Partial secondarily generalized seizures

II. Generalized seizures (bilaterally symmetrical and without local onset)

  • Absence seizures
  • Myoclonic seizures
  • Clonic seizures
  • Tonic seizures
  • Tonic-clonic seizures
  • Atonic seizures (astatic)

III. Unclassified epileptic seizures (inadequate or incomplete data)

A partial seizure starts when there is initial activation of a limited number of neurons in part of one hemisphere. It may spread to other parts and may become a generalized seizure.

A generalized seizure happens when there is involvement of both hemispheres at the onset of seizure.

If you preserve your awareness during your seizure that means you have a simple partial seizure. You may have motor, sensory, or autonomic or psychic symptoms during them.

There is loss of awareness during complex partial seizures. Sometimes they may start as simple partial and then evolve into complex partial seizures. Sometimes complex partial seizures end as it is or sometimes they progress into grand mal seizures.

After a complex partial seizure there is always some confusion which may last from few minutes to few hours. It is called postictal confusion. During complex partial seizures the patient may have aura followed by staring into face with or without automatisms. An automatism is a coordinated involuntary motor activity occurring during the state of clouding of consciousness. Most frequent automatisms are oro-facial or hand automatisms. The other kinds are gestural, ambulatory, or verbal automatisms.

Generalized tonic clonic seizures may start os grand mal or evolve from complex partial seizures. Initially the patient gets stiff during tonic phase. He may fall due to rigidity of body. During tonic phase all muscles contract including respiratory muscles. There is obstruction of airways due to muscle contraction. Tongue biting and urinary incontinence happen during this phase. The patient may sound crying, called ictal cry. Tonic phase is followed by generalized convulsions of all limbs. The clonic phase usually lasts few minutes. Then seizure ends and the patient goes into a deep sleep afterwards. There is confusion after seizures. Duration may vary form few minutes to hours. Usually headache occurs afterwards, too.

Absence seizures are brief seizures with staring spells. The patient returns to baseline very quickly. Kids who have absence seizures usually grow out of it. Myoclonic seizures are brief involuntary jerks of limbs. They are more frequent in the mornings. It may cause trouble while brushing teeth or drinking coffee in the mornings. Sometimes it can involve the legs then it may cause person to fall. Atonic seizures are associated with sudden loss of muscle tonus in body and may present as head drops or sudden falls with impaired awareness. On the other hand tonic seizures present as tonic posturing of extremities. They usually involve upper extremities and are very brief.

What should I do after first seizure?

After a first seizure anyone without a clear etiology (reason) should see a neurologist and have a full neurological evaluation to determine the cause of the seizure. The decision for further investigations and treatment will depend on this initial evaluation. The tests to consider in evaluation of patients with first seizures are Brain MRI, EEG, and certain laboratory tests.

What is my risk of having a second seizure after the first seizure?

If your first seizure occurred without any provoking factor, your recurrence (having another seizure) risk depends on various factors such as findings in your work up, brain imaging, EEG, neurological exam, family history, childhood history, developmental history, history of learning disability in the past, etc.

If all of factors mentioned above is negative that means you have a low risk for recurrence. If your EEG or your imaging is abnormal or if you have had two unprovoked seizures with all other factors above were normal puts you at medium risk for recurrence group.

If your EEG and imaging are abnormal or you have had two unprovoked seizures with either EEG or imaging abnormal that means you have a high risk for recurrence.

Your physician should make the decision whether or not to treat you after first seizure based on the risk of recurrence and also the impact of recurrence of a single seizure due to certain conditions such as socio-economic conditions, high risk occupation, risks of injuries due to falls in elderly and in patients on anticoagulation.

What factors can lower the seizure threshold?

Certain situations can lower the seizure threshold and therefore trigger a seizure in people with epilepsy:

  • Lack of sleep or erratic sleep schedules
  • Excessive alcohol
  • Physical stress
  • Emotional stress
  • Flashing or flickering lights (rare, only in certain types of epilepsy)
  • Hyperventilation
  • Menstruation
  • Recreational drugs
  • Medications (Sudafed, sedating antihistamines, tricyclic antidepressants, wellbutrin, interferons, some antibiotics such as ciprofloxacin, levofloxacin etc.)

What are other conditions that may mimic epilepsy?

  1. Cardiac syncope
  2. Vasovagal syncope
  3. Transient ischemic attacks and stroke
  4. Complicated migraine
  5. Transient global amnesia
  6. Hyperventilation
  7. Sleep disorders
  8. Movement disorders
  9. Panic attacks
  10. Anxiety episodes
  11. Mood disorders
  12. Conversions
  13. Malingering
  14. Drug toxicity

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