I. Definition.
Epilepsy is a chronic brain disorder caused by genetic and brain injury and characterized by abnormal brain neuronal discharges and transient and recurrent brain dysfunction manifested as different disorders of consciousness, mental, motor, sensory, and vegetative nerves. Seizures are complex because their manifestations are related to the location, extent and intensity of the discharges. Each has a sudden onset, short duration, and rapid recovery, but can sometimes be continuous. The prevalence of epilepsy is 3-6 per 1,000, and most patients with epilepsy start in childhood.
Second, etiology.
The causative factors of epilepsy are threefold.
1. genetic factors.
2, brain injury: refers to the damage to the brain from embryonic onset to all aspects of factors before and after the onset, it holds including abnormal brain development, cranial trauma, tumors, intracranial inflammation, cerebrovascular disease, cerebral parasitosis, cerebral hypoxia, metabolic disorders, endocrine disorders, poisoning, etc.
3. Factors affecting epilepsy.
(1) Physiological factors: age and sex, menstruation and pregnancy, sleep and wakefulness.
(2) Sensory stimuli.
(3) Other factors: fever, excessive drinking, hyperventilation, alcoholism, lack of sleep, overexertion, etc.
(3) Classification of the etiology of epilepsy.
(1) Idiopathic (primary) epilepsy: epilepsy in which the brain fails to find the relevant structural changes and metabolic abnormalities, and is more closely related to genetic factors.
2. Symptomatic (secondary) epilepsy: that is, epilepsy with clear brain lesions or metabolic disorders.
3. Cryptogenic epilepsy: It is suspected symptomatic epilepsy, but the cause has not been found.
4. Clinical features of epilepsy.
1, the diversity of symptoms: can be manifested as a single consciousness, mental, motor, sensory or vegetative nerve dysfunction, or both, that is, manifested as two or more symptomatic seizures.
2. Recurrent seizures: Recurrent seizures are a characteristic of the course of epilepsy, but the frequency and duration of seizures are different for different types and different patients.
The former is the basis for the onset of epilepsy (endogenous) and the latter is the condition for the onset of epilepsy (exogenous).
V. Basis for confirming the diagnosis
The main reliance is on clinical manifestations, EEG waveforms and the effect of antiepileptic drugs. For a patient, the initial diagnosis does not require the three conditions to be essential, but in the diagnostic process, all three are important for different patients, especially for the establishment of the final diagnosis, and for most patients, all three conditions are essential.
(i) Clinical manifestations.
The initial diagnosis can be made in most patients based on the clinical features of the seizure. It is even more helpful if the physician is witnessing the patient’s seizures to determine if they are epileptic. Typical seizure manifestations are decisive in determining epilepsy.
(ii) EEG waveforms.
1. Sporadic spikes: Spikes are one of the most characteristic manifestations of epileptic focal discharges. Spikes appearing on a slow-wave background are more significant and often suggest that they come from the epileptic focus or its nearby area. Spike-waves appearing on a normal background are generally of lower amplitude and longer period, and are mostly propagated from distant foci. Disseminated spike-waves are increasing in number, and those that eventually manifest as spike-wave rhythms tend to lead to clinical seizures.
2. Disseminated spike-wave: It has the same meaning as spike-wave. It may be caused by the incomplete synchronization of spike-wave discharges of most neurons in larger epileptic foci; or by the propagation of distant spike-wave foci, which prolongs the duration (period) of spike-wave.
3, spike-and-slow waves or spike-and-slow integrated waves: Whenever spike or spike waves are combined with slow waves with a period of 300-400 ms, they are called spike-and-slow waves or spike-and-slow integrated waves.
4.Multi-spike wave group: 2-6 spike waves in a family appear alone (not combined with slow waves), and sometimes one or more slow waves are attached (multi-spike slow waves combined), mainly seen in myoclonic epilepsy, when spike waves appear continuously, it is mostly a manifestation of grand mal seizure (its frequency can reach 10-30 times/sec).
5.High-amplitude dysrhythmia: Most high-amplitude spike waves or spike waves appear in a chaotic and irregular combination with most slow waves, mainly seen in infantile spasms.
Seizure rhythm waves: Paroxysmal, high-amplitude slow rhythms (δ rhythm or theta rhythm), alpha rhythm or fast rhythm appear on the background EEG, which is also generally considered as a symptom of epileptic discharge.
A normal EEG examination cannot exclude epilepsy, nor can the presence of epileptic waveforms on the EEG without clinical epileptic seizures be diagnosed as epilepsy. It can only indicate the presence of risk factors.
(iii) Effect of antiepileptic drugs
Experience has shown that correct drug treatment can lead to satisfactory results in more than 90% of patients.