What Is Epilepsy?

Epilepsy is a chronic neurological disorder characterized by recurrent unprovoked seizures. If you have had more than one seizure without any identified provoking factor such as head trauma, fever, alcohol intake, illicit drug abuse, etc. you may have epilepsy. Between seizures, most people with epilepsy are completely normal.

Epilepsy can be inherited. Certain genes responsible for inherited epilepsy were identified. But there is still a lot to be discovered about genetic aspects of epilepsy. Some epilepsy cases are acquired. Certain conditions such as a birth defects and injuries, head trauma, brain infections, and brain tumors can result in epilepsy. In more than two thirds of cases there is no identified underlying etiology for epilepsy.

Not everyone who has had a seizure has epilepsy. About 10% of people will have a seizure during their lifetime; most of these are “provoked” seizures. These people may never have another seizure, and therefore do not have epilepsy.

What Kind of Epilepsy I have?

In addition to seizure classification, experts developed classification of epilepsy syndromes.

International Classification of Epilepsies

1. Localization-related (focal, local, partial)

  • Idiopathic
  • Symptomatic
  • Cryptogenic

2. Generalized

  • Idiopathic
  • Symptomatic
  • Cryptogenic

3. Undetermined epilepsies

  • With both generalized and focal seizures
  • Without unequivocal generalized or focal features

4. Special syndromes

With both localized or generalized epilepsies, idiopathic subdivision means there is no known cause of seizures, but causes can be genetic. Symptomatic means there is a known cause. Cryptogenic means there is no visible cause, but there is a suspected or hidden cause.

Temporal lobe epilepsy fits well into symptomatic localization related epilepsy if MRI Brain shows scar tissue in the temporal lobe.

Autosomal dominant frontal lobe epilepsy is classified as idiopathic localization related epilepsy.

If tumor, stroke, or trauma related injury seen in frontal lobe is the cause of seizure, it will be considered as symptomatic localization related epilepsy.

Localization related epilepsies are those with area of abnormality in the brain where seizures originate. These regions can be frontal, temporal, occipital, or parietal lobes.

Generalized epilepsy means the seizures originate from both hemispheres at the onset. Generalized epilepsies are classified as idiopathic, symptomatic or cryptogenic. Idiopathic generalized epilepsy syndrome include juvenile myoclonic epilepsy, childhood absence epilepsy, and juvenile absence epilepsy syndromes. Under symptomatic generalized epilepsy classification, Lenox- Gastaut syndrome and infantile spasms are well known.

Landau-Kleffner syndrome is classified as an uncommon epilepsy syndrome.

Special epilepsy syndromes include febrile seizure and reflex epilepsy such as photosensitive epilepsy, reading epilepsy, and others.

Why experts did classify seizures and epilepsy syndromes? What was the purpose?

Classification of the epilepsy syndrome is very important in determining further tests for evaluation and choosing the most appropriate medication to control seizures. For classification routine EEG and clinical and family history may not be adequate. Further tests such as video EEG monitoring is the gold standard test in determining type of epilepsy syndrome and seizures you have. If you have partial seizures, imaging techniques such as magnetic resonance imaging of brain, PET scan will be utilized to localize focus of seizures. Ictal SPECT is another way to find seizure focus and performed when clinical seizure is captured.

International classification of epilepsy syndromes and seizures are used by your doctor not just classifying what kind of epilepsy and seizure type you have, but also conducting the needed tests and determining type of treatment.

Why do I have epilepsy? Why me?

This is one of the most common questions the patients ask. There are many different underlying causes of epilepsy. Often the cause of your epilepsy can not be identified. Some of the known causes of epilepsy are as follows:

  • Head injuries: Concussion (brief loss of consciousness) is considered to be mild head trauma, and it may increase the risk of epilepsy slightly. Moderate or severe head injury with prolonged loss of consciousness or brain hemorrhage significantly increase the risk of epilepsy.
  • Brain infections such as meningitis, encephalitis, and brain abscess
  • Stroke: Ischemic (caused by lack of blood flow to parts of the brain) or hemorrhagic (bleeding into brain tissue) strokes increase the risk of epilepsy.
  • Alcohol: Heavy drinking (intoxication) or abrupt stopping of alcoholic beverages (“withdrawal” seizures) can cause an increased risk of epilepsy.
  • Brain tumors
  • Degenerative brain diseases, such as Alzheimer Disease and Parkinson Disease
  • Demyelinating diseases such as multiple sclerosis
  • Mental retardation and cerebral palsy
  • Cortical dysplasia and migration disorders: Here there is abnormality of brain growth, migration and maturation of the neuronal tissue. The neuronal tissue which migrated to inproper positions in brain result in “tangles” of neurons. These tangles have abnormal electrical connections, and therefore predispose brain to seizures.
  • Genetic predisposition: Some types of epilepsy run in families. If you have generalized epilepsy such as juvenile myoclonic epilepsy or childhood absence seizures, there is three to four fold increase in your first-degree relatives (parents, siblings, and children). First-degree relatives of patients with partial seizures have higher risk of developing epilepsy as the general population.
  • Age: The risk of seizures is highest in young children and in the elderly.
  • Gender: The incidence of epilepsy is higher in males than females. This may suggest that gender may be important in the development of epilepsy.
  • Febrile seizures during infancy increase the risk of epilepsy development later.
  • Connective tissue disorders, like vasculitis are associated with increased risk of epilepsy, if there is central nervous system involvement.
  • Cancer with spread to brain and side effects of chemotherapy
  • Some other disorders such as mitochondrial diseases, migraine, and psychiatric conditions are also associated with increased risk of epilepsy.
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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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What Tests are Used to Diagnose Epilepsy?

Is there a certain type of test needed for epilepsy diagnosis?

What Tests are Used to Diagnose Epilepsy?The diagnosis of epilepsy is a clinical diagnosis. Your doctor will diagnose epilepsy based on the information from the history, physical examination, EEG, and brain imaging studies.

There are certain tests to support the diagnosis of epilepsy such as electroencephalogram (EEG) and brain imaging. EEG amplifies electrical activity in brain and records and displays them on a computer screen. In the past EEG displays were on paper. Abnormalities such as spikes, sharp and slow waves occur during seizures. In between seizures EEG may not show any abnormalities. EEGs in between seizures can be normal. Multiple repeats of EEG tests will increase the chance to catch abnormalities supporting epilepsy diagnosis. There is no blood test for epilepsy.

Imaging such as computed axial tomography of head and magnetic resonance imaging of brain provide detailed information about brain structure. They can reveal birth defects, tumor, scars, and stroke, all of which can cause epilepsy.

Why EEG? What is the purpose?

Electroencephalogram (EEG) is a test to record brain activities. It amplifies brain activities and displays them as waves. EEG machines record the brain activities through the electrodes. The electrodes are glued or pasted on the scalp. Amplifiers in the machine magnify the brain signals. The recordings are written on paper or digitized and displayed on the computer monitor. Spike and wave is a distinctive pattern and occurs in patients with epilepsy.

EEGs are to support and eventually confirm the diagnosis and also can be helpful to classify the type of epilepsy syndrome. For example typical pattern 3 Hz spike and wave is seen in patients with idiopathic generalized epilepsy. Determining the type of epilepsy is very important in choosing therapeutic options, becasue some anti-epileptics may not control certain seizures.

Before EEG test you may be asked to be sleep deprived. It is very well known that sleep deprivation is a seizure trigger. Also it will help you sleep during EEG test, which can improve chance of detecting abnormalities on EEG test.

During EEG test you may be provoked by flashing lights and hyperventilation. These provocative techniques can cause seizures in some patients. Flashing lights trigger seizures in patients with photosensitive epilepsy. Hyperventilation lowers seizure threshold and can cause seizures.

CAT Scan versus MRI? What is the difference?

What Tests are Used to Diagnose Epilepsy?CAT scan was the first Xray machine to rely on computer in brain imaging. It uses Xrays to take the picture of brain. It is very sensitive test in identifying acute changes such as bleeding in the brain or skull fractures.

On the other hand, magnetic resonance imaging (MRI) employs magnetic field to produce the image of brain. There is no risk of radiation with MRI. It is superior to CAT scan in delineating the structural abnormalities in the central nervous system suc h as scarring, inflammation, infection, stroke, and tumor. An MRI may need to be conducted in almost all patients with new ons et epilepsy.

Single Photon Emission Computed Tomography (SPECT)

SPECT is another nuclear medicine imaging study. It is used when patients are considered for epilepsy surgery. It identifies the seizure focus by detecting altered focal blood flow. Increased blood flow is seen in epileptic tissue as the seizure starts.

The drawback of this test is the patient must have had seizure few minutes prior to the testing. At the onset of seizure the patient is injected a radioactive material. SPECT tracks the uptake of this radioactive substance in the brain to identify the epileptic tissue. Like PET, SPECT is not a routine study, utilized when patients are considered for epilepsy surgery. It is performed in inpatient hospital setting.

Positron Emission Tomography (PET)

PET is a nuclear medicine imaging test that has been used to localize the area of abnormality causing seizures. It is an additional supportive study to EEG and brain MRI in localizing the seizure focus. This test is not a routine test and performed when epilepsy surgery is considered to optimize seizure control in patients with uncontrolled seizures.

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