An epileptic seizure is a paroxysmal disorder characterized by an abnormal, excessive, hypersynchronous discharge of neurons which results in an alteration of function of the patient. This alteration of function can be quite dramatic such as during a generalized tonic–clonic (grand mal) seizure or much more subtle such as during an absence (petit mal) seizure. Epilepsy is a condition characterized by repeated, unprovoked seizures. If the seizures are consistently provoked, such as by fever or hypoglycemia, the term epilepsy should not be used. Epilepsy is not a single disorder, but rather a symptom of underlying brain dysfunction.
A classification of epileptic seizures and syndromes is an essential step in developing communication and provides a basis for an understanding of the underlying processes of epilepsy. A classification system provides guidance in determining the diagnostic evaluation, treatment, and prognosis (Table 1–1). However, no single classification code can cover the multiple aspects of epilepsy including behavioral and electroencephalographic (EEG) features, age of onset, and etiology (including genetic susceptibility and acquired insults). In addition, limited knowledge regarding the basic mechanism does not permit classification on the physiopathology of the disorder.
TABLE 1–1.CLASSIFICATION OF EPILEPTIC SEIZURES |Favorite Table|Download (.pdf) TABLE 1–1. CLASSIFICATION OF EPILEPTIC SEIZURES
Focal (Partial) Seizures
Without impairment of consciousness or awareness (simple partial seizures)
With observable motor or autonomic components
Phonatory (vocalization or arrest of speech)
Focal motor with march (Jacksonian)
Autonomic symptoms or signs (including epigastric sensation, pallor, sweating, flushing, piloerection, and pupillary dilation)
With selective sensory or psychic phenomena
Psychic symptoms (disturbance of higher cerebral function)
With impairment of consciousness (complex partial seizures)
Focal followed by impairment of consciousness
With impairment of consciousness at onset
Focal seizure evolving to bilateral, convulsive seizures (involving tonic, clonic, or tonic and clonic complexes)
Absence with special features
Absence with eyelid myoclonic
The first modern classification system of seizures was proposed in 1969 by an ad hoc committee of the International League Against Epilepsy.1 In 1981, the classification was revised.2 It is based on two criteria: the clinical features and the EEG features of the seizures. Seizures are classified into two broad categories: (a) ...