International Classification of Epileptic Seizures

I. Focal onset seizures

B) Focal onset seizures with impaired awareness

1. Focal seizures at onset, followed by impairment of awareness

• With focal features, no automatsm
• With automatisms

2. With impairment of awareness at onset

• With impairment of awareness only
• With automatisms

C) Focal seizures evolving to bilateral tonic clonic seizures

1. Focal seizures evolving to bilateral tonic clonic seizures

2. Focal seizures with impaired awareness evolving to bilateral tonic clonic seizures

3. Focal seizures with awareness evolving to impaired awareness evolving to bilateral tonic clonic seizures

III. Unknown onset

A) Motor

B) Non motor

C) Unclassified

Classification of Epilepsy syndromes

International Classification of Epilepsies and Epileptic Syndromes

1. Focal epilepsies and syndromes

1.1. Idiopathic with age-related onset

• A. Benign childhood epilepsy with centrotemporal spikes
• B. Childhood epilepsy with occipital paroxysms

1.2. Symptomatic

• A. Chronic progressive epilepsia partialis continua of childhood
• B. Syndromes characterized by seizures with specific modes of precipitation
• C. Temporal lobe epilepsies
• D. Frontal lobe epilepsies
• E. Parietal lobe epilepsies
• F. Occipital lobe epilepsies

1.3. Crytopgenic

2. Generalized epilepsies and syndromes

2.1. Idiopathic, with age-related onset (listed in order of age)

• A. Benign neonatal familial convulsions
• B. Benign neonatal convulsions
• C. Benign myoclonic epilepsy in infancy
• D. Childhood absence epilepsy (pyknolepsy)
• E. Juvenile absence epilepsy
• F. Juvenile myoclonic epilepsy (impulsive petit mal)
• G. Epilepsy with grand mal seizures on awakening
• H. Other generalized idiopathic epilepsies not defined above
• I. Epilepsies with seizures precipitated by specific modes of activation

2.2. Idiopathic and/or symptomatic (listed in order of age)

• A. West syndrome (infantile spasms)
• B. Lennox-Gastaut syndrome
• C. Epilepsy with myoclonic-astatic seizures
• D. Epilepsy with myoclonic absences

2.3. Symptomatic

• A. Nonspecific etiology
  - a. Early myoclonic encephalopathy
  - b. Early infantile epileptic encephalopathy with suppression burst
  - c. Other symptomatic generalized epilepsies not defined above
• B. Specific etiology
  - a. Epileptic seizures may complicate many disease states

Epilepsies and syndromes undetermined as to whether they are focal or generalized

3.1. With both generalized and focal seizures

• A. Neonatal seizures
• B. Severe myoclonic epilepsy in infancy
• C. Epilepsy with continuous spike waves during slow-wave sleep
• D. Acquired epileptic aphasia (Landau-Kleffner syndrome)
• E. Other undetermined epilepsies not defined above

3.2. Without unequivocal generalized or focal features

Special syndromes

4.1. Situation-related seizures

• A. Febrile convulsions
• B. Isolated, apparently unprovoked epileptic events
• C. Seizures related to other identifiable situations such as stress, hormonal changes, drugs, alcohol, or sleep deprivation

Classification of the Epilepsies.

Common seizure types

Focal seizures

With awareness (previous terminology - Simple partial seizures)

These are defined as partial seizures in which consciousness is not impaired.

With impaired awareness (previous terminology-Complex partial seizures)

Complex partial seizures are those in which consciousness is impaired. Both simple and complex partial seizures imply focal cerebral disease and seizures can arise from any cortical region, the most common sites being the frontal and temporal lobes.

With awareness

Motor manifestations can include jerking, spasm or posturing, speech arrest, dysarthria, choking sensations, version of the head or eyes or, less commonly, rotation of the whole body can occur in epilepsy arising in many cortical areas. Visual phenomena such as flashing lights and colors occur if the calcarine cortex is affected. A rising epigastric sensation is the most common manifestation of a simple partial seizure arising in the mesial temporal lobe. Illusions of size (macropsia, micropsia), shape, weight, distance or sound are usually features of temporal or parieto-occipital epileptic foci. Dysmnestic symptoms (disturbance of memory) such as flashbacks, déjà vu, jamais vu, or distortions of memory are most common in mesial temporal lobe seizures although also occur in inferior frontal or lateral temporal lobe seizures. Hallucinations of taste, usually an unpleasant taste, are a frequent symptom of temporal lobe epilepsy. Visual hallucinations can vary greatly in sophistication from simple colours or flashing lights in epilepsy arising in calcerine cortex

With impaired awareness

It is possible to identify three distinct components: the aura, the absence or a dialeptic phase (loss of consciousness) and the automatism in a complex partial seizure. These arise from the temporal lobe in about 60% of cases. The aura is in effect a simple partial seizure. It is usually short-lived, lasting a few seconds. During the dialeptic phase the patient usually appears to be staring, is unresponsive to the environment and has no memory for the ensuing period. Automatisms are defined as involuntary motor actions that occur during or in the aftermath of epileptic seizures, in a state of impaired awareness. The most common automatisms are oro-alimentary automatisms in which orofacial movements occur such as chewing, lip smacking, swallowing or drooling, gestural automatisms include fiddling movements with the hands, tapping, patting or rubbing, ordering and tidying movements. The patient is usually totally amnesic for the events of the automatism

Generalized seizures

In generalized seizures consciousness is impaired from the onset of the attack, motor changes are bilateral and more or less symmetric, and the EEG patterns are bilateral and grossly synchronous and symmetrical over both hemispheres.

Typical absence seizure (petit mal seizure)

There is an abrupt sudden loss of consciousness (the absence) and cessation of all motor activity. There is no fall. The patient is not in contact with the environment, often appears glazed, vacant, staring or dreaming. The attack ends as abruptly as it started, and previous activity is resumed as if nothing had happened and there is no post seizure confusion. The patient is often unaware that an attack has occurred. The EEG during a typical absence is diagnostic, shown high voltage, regular, symmetric and synchronous 3 Hz spike-wave paroxysms.

Generalised tonic clonic seizure

This is the type of seizure most people are familiar with. This is the convulsion or fit in layman term. There is abrupt loss of consciousness, sometimes with the epileptic cry (a loud sound), tonic stiffening (and the patient falls if standing) initially in flexion of the limbs but then in axial extension, with the eyes rolled up, the jaw shut (leading to tongue bite), the limbs stiff, adducted and extended, and the fists clenched. Respiration ceases and there is cyanosis. The eyes remain open and the pupils dilated and unreactive. There are frequently heart rate changes, which are sometimes marked and can take the form of tachycardia or bradycardia and even asystole. This tonic stage lasts on average 10–30 seconds and is followed by the clonic phase, during which convulsive movements, usually of all four limbs, jaw, and facial muscles occur. Breathing is laborious and arrest of respiration can occur, saliva (sometimes bloodstained owing to tongue biting) may froth from the mouth. The convulsive movements decrease in frequency (eventually to about four clonic jerks per second), and increase in amplitude as the attack progresses. The attack is usually followed by a period of flaccidity of the muscles and consciousness is slowly regained.

Myoclonic seizure

There is brief contraction of a muscle, muscle group or several muscle groups brought about by a cortical discharge. It can be single or repetitive, varying in severity from an almost imperceptible twitch to a severe jerking, resulting, for instance, in a sudden fall or the propulsion of handheld objects. Recovery is immediate, and the patient often maintains that consciousness was not lost

Causes of epilepsy

Epilepsy is often a multifactorial condition, genetic and environmental factors often play a part in its clinical manifestations. Genetic, congenital and perinatal conditions are the most common causes of early childhood onset epilepsy, whereas in adult life, head injury, vascular disease, tumors are common causes. In India endemic infections such as cysticercosis, tuberculosis, meningitis and encephalitis are common causes. Cerebral palsy a non-specifi c term that covers several prenatal and perinatal pathologies is strongly associated with epilepsy. AV malformations, cavernomas, degenerative disorders like Alzheimer dementia can cause seizures and epilepsy. Head trauma is an important cause of epilepsy (post traumatic epilepsy). Neuro-cysticercosis is the most common parasitic disease of the CNS. Epilepsy is the most common clinical manifestation and usual presenting symptom and neuro-cysticercosis a major cause of epilepsy in India.

Differential diagnosis of epilepsy

Differential diagnoses of transient neurological dysfunction is broad and Epileptic seizures