- Epilepsy
- (seizure disorder): When nerve cells in the brain fire electrical impulses at a rate of up to four times higher than normal, this causes a sort of electrical storm in the brain, known as a seizure. A pattern of repeated seizures is referred to as epilepsy. Known causes include head injuries, brain tumors, lead poisoning, maldevelopment of the brain, genetic and infectious illnesses. But in fully half of cases, no cause can be found. Medication controls seizures for the majority of patients.
* * *A chronic disorder characterized by paroxysmal brain dysfunction due to excessive neuronal discharge, and usually associated with some alteration of consciousness. The clinical manifestations of the attack may vary from complex abnormalities of behavior including generalized or focal convulsions to momentary spells of impaired consciousness. These clinical states have been subjected to a variety of classifications, none universally accepted to date and, accordingly, the terminologies used to describe the different types of attacks remain purely descriptive and nonstandardized; they are variously based on 1) the clinical manifestations of the seizure (motor, sensory, reflex, psychic or vegetative), 2) the pathologic substrate (hereditary, inflammatory, degenerative, neoplastic, traumatic, or cryptogenic), 3) the location of the epileptogenic lesion (rolandic, temporal, diencephalic regions), and 4) the time of life at which the attacks occur (nocturnal, diurnal, menstrual, etc.). SYN: convulsive state, epilepsia, falling sickness. [G. epilepsia, seizure]- anosognosic e. e. characterized by attacks of which the person is unaware. SYN: anosognosic seizures.- automatic e. SYN: psychomotor e..- autonomic e. episodes of autonomic dysfunction presumably due to diencephalic irritation. SYN: diencephalic e., vasomotor e., vasovagal e..- benign childhood e. with centrotemporal spikes a specific e. syndrome beginning in childhood and remitting in adolescence, characterized by nocturnal simple partial motor seizures or generalized tonic-clonic seizures. EEG shows centrotemporal spikes that are activated by sleep and an otherwise normal EEG background.- centrencephalic e. an imprecise term referring to e. characterized electroencephalographically by bilateral synchronous discharges, and clinically by absence or generalized tonic-clonic seizures.- childhood absence e. a generalized e. syndrome characterized by the onset of absence seizures in childhood, typically at age six or seven years. There is a strong genetic predisposition and girls are affected more often than boys. EEG reveals generalized 3-Hz spike-wave activity on a normal background. Prognosis for remission is good if the patient does not also have generalized tonic-clonic seizures. SEE ALSO: absence. SYN: petit mal e., pyknolepsy.- childhood e. with occipital paroxysms a benign e. syndrome characterized by frequent occipital spikes often activated by eye closure. It has a seizure semiology that includes visual manifestations; not always remitting later in life.- complex precipitated e. a form of reflex e. initiated by specialized sensory stimuli, e.g., certain visual patterns.- diencephalic e. SYN: autonomic e..- focal e. e. of various etiologies characterized by focal seizures or secondarily generalized tonic-clonic seizures. Ictal symptoms are often related to the brain region where the seizure begins focally. SYN: cortical e., local e., localization-related e. (2), partial e..- frontal lobe e. a localization-related e. with seizures originating in the frontal lobe. A variety of clinical syndromes exist depending on the exact localization of seizures and clinical semiology of the seizure type. Frontal lobe epilepsies have been divided into several specific syndromes including the syndrome of supplementary motor seizures, cingulate seizures, anterior frontal polar region seizures, orbital frontal seizures, dorsolateral seizures, opercular seizures, and seizures of the motor cortex.- generalized e. a major category of e. syndromes characterized by one or more types of generalized seizures.- idiopathic e. 1. an e. without evident cause; term often used to describe the genetic epilepsies; 2. SYN: generalized tonic-clonic seizure.- intractable e. e. not adequately controlled by medication. SYN: pharmacoresistent e..- jacksonian e. SYN: jacksonian seizure.- juvenile absence e. a generalized e. syndrome with onset around puberty, characterized by absence seizures and generalized tonic-clonic seizures. EEG often shows a greater than 3 Hz generalized spike wave pattern.- juvenile myoclonic e. an e. syndrome typically beginning in early adolescence, and characterized by early morning myoclonic jerks that may progress into a generalized tonic-clonic seizure. A genetic disorder : some families have had gene linkage to chromosome-6. The EEG is characterized by generalized polyspike and wave discharges at 4–6 Hz.- Kojewnikoff e. SYN: epilepsia partialis continua.- masked e. a form of e. characterized by a paroxysmal disturbance, such as headache or vomiting, associated with an epileptic electroencephalographic pattern.- matutinal e. a form of e. which occurs on awakening.- myoclonic astatic e. a petit mal variant characterized by atonic (drop attacks) and tonic or tonic-clonic attacks in neurologically disabled (hemiplegic, ataxic, etc.) children with mental retardation; characterized in EEG by 2/sec spike and wave discharges; usually progresses in spite of medication.- myoclonus e. [MIM*159800 and MIM*220300] a clinically diverse group of e. syndromes, some benign, some progressive. Many are hereditary with mendelian and nonmendelian mitochondrial inheritance. All are characterized by the occurrence of myoclonus, which may be limited or predominate in the condition. Specific syndromes include cherry red spot myoclonus syndrome, ceroid lipofuscinosis, myoclonic e. with ragged red fibers, and Baltic myoclonus. SYN: localization-related e. (1).- occipital lobe e. a localization-related e. where seizures originate from the occipital lobe. Symptoms commonly include visual abnormalities during seizures.- parietal lobe e. a localization-related e. where seizures originate within the parietal lobe. Seizure semiology may involve abnormalities of sensation.- partial e. SYN: focal e..- pharmacoresistent e. SYN: intractable e..- posttraumatic e. a convulsive state following and causally related to head injury; with brain damage either manifested clinically or ascertained by special examinations such as computed tomography. To assume causal relationship, the individual must have had no previous e., no cerebral disease, and no other brain trauma. The attacks should have started, depending on the severity of the wounding, within 3 months to 2 years of the alleged trauma and be of a type compatible with the site of injury and the EEG abnormalities.- primary generalized e. e. without evidence of focal or multifocal central nervous system disease. Seizures are generalized from onset, both by EEG and clinical criteria. Often a pure genetic form of e.. SEE ALSO: generalized tonic-clonic seizure.- procursive e. a psychomotor attack initiated by whirling or running.- psychomotor e. attacks with elaborate and multiple sensory, motor, and/or psychic components, the common feature being a clouding or loss of consciousness and amnesia for the event; clinical manifestations may take the form of automatisms; emotional outbursts of temper, anger or show of fear; motor or psychic disturbances; or may be related to any sphere of human activity. Electroencephalographically, the attack is characterized by spike discharges in the temporal lobe, especially in sleep. SEE ALSO: procursive e., visceral e., uncinate e.. SYN: automatic e..- reflex e. seizures which are induced by peripheral stimulation; e.g., audiogenic, laryngeal, photogenic, or other stimulation. SYN: sensory precipitated e..- rolandic e. a benign, autosomal dominant form of e. occurring in children, characterized clinically by arrest of speech, muscular contractions of the side of the face and arm, and epileptic discharges electroencephalographically. [Luigi Rolando]- secondary generalized e. a group of e. syndromes of diverse etiologies with diffuse or multifocal cerebral involvement. Patients typically have a variety of generalized seizure types, including tonic, atonic, myoclonic, atypical absence, and generalized tonic-clonic seizures. Partial seizures may also occur. One classic syndrome is the Lennox-Gastaut syndrome. SYN: symptomatic e..- somnambulic e. postictal automatism in which the patient walks or runs about exhibiting natural behavior of which he or she has no subsequent remembrance.- supplementary motor area e. a localization-related e. syndrome in which seizures originate from the supplementary motor area of the mesial frontal lobe. Typical seizure semiology includes sudden bilateral tonic movements, vocalization, and preservation of consciousness. Attacks are often nocturnal.- symptomatic e. SYN: secondary generalized e..- temporal lobe e. a localization-related e. with seizures originating from the temporal lobe, most commonly the mesial temporal lobe. The most common pathology is hippocampal sclerosis. SYN: uncinate fit.- tornado e. a type of focal e. or partial seizure with an aura of severe vertigo and a feeling of being drawn up into space.- uncinate e. a form of psychomotor e. or complex partial seizure initiated by a dreamy state and hallucinations of smell and taste, usually the result of a medial temporal lesion. SYN: uncinate attack.- visceral e. e., usually psychomotor, in which the attacks are initiated by visceral symptoms or sensations; most cases have their focus in the temporal lobe.- e. with grand mal seizures on awakening generalized e. syndrome characterized by onset in the second decade of life, typically with generalized tonic-clonic seizures, of which most occur shortly after awakening (regardless of the time of day) and are exacerbated by sleep deprivation. There is a genetic predisposition and EEG shows one of several generalized patterns of interictal discharges; photosensitivity is common.- e. with myoclonic absences a form of generalized e. characterized by absence seizures, severe bilateral rhythmic clonic jerks often associated with tonic contraction, and an EEG 3 Hz spike and wave pattern. Age of onset is usually around seven years and males are more often affected.
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ep·i·lep·sy 'ep-ə-.lep-sē n, pl -sies any of various disorders marked by abnormal electrical discharges in the brain and typically manifested by sudden brief episodes of altered or diminished consciousness, involuntary movements, or convulsions see GRAND MAL, PETIT MAL focal epilepsy, JACKSONIAN EPILEPSY, myoclonic epilepsy, temporal lobe epilepsy* * *
n.a disorder of brain function characterized by recurrent seizures that have a sudden onset. The term idiopathic is used to describe epilepsy that is not associated with structural damage to the brain. Seizures may be generalized or partial. Generalized epilepsy may take the form of major, or tonic-clonic, seizures (formerly called grand mal), in which, at the onset, the patient falls to the ground unconscious with his muscles in a state of spasm. The lack of any respiratory movement may result in a bluish discoloration of the skin and lips (cyanosis). This - the tonic phase - is replaced by convulsive movements (the clonic phase) when the tongue may be bitten and urinary incontinence may occur. Movements gradually cease and the patient may rouse in a state of confusion, complaining of headache, or may fall asleep.Partial epilepsy may be idiopathic or a symptom of structural damage to the brain. In one type of partial idiopathic epilepsy, often affecting children, the seizures take the form of absences (formerly called petit mal in children): brief spells of unconsciousness lasting for a few seconds, during which posture and balance are maintained. The eyes stare blankly and there may be fluttering movements of the lids and momentary twitching of the fingers and mouth. In children the electroencephalogram characteristically shows bisynchronous wave and spike discharges (3 per second) during the seizures and at other times. Attacks are sometimes provoked by overbreathing or intermittent photic stimulation. As the stream of thought is completely interrupted, children with frequent seizures may have learning difficulties. This form of epilepsy seldom appears before the age of three or after adolescence. It often subsides spontaneously in adult life, but it may be followed by the onset of major or partial epilepsy.In partial epilepsy due to brain damage, called focal epilepsy, the nature of the seizure depends upon the location of the damage in the brain. In a Jacksonian motor seizure the convulsive movements might spread from the thumb to the hand, arm, and face (this spread of symptoms is called the march). Temporal lobe (or psychomotor) epilepsy is caused by disease in the cortex of the temporal lobe or the adjacent parietal lobe of the brain. Its symptoms may include hallucination of smell, taste, sight, and hearing, paroxysmal disorders of memory, and automatism. Throughout an attack the patient is in a state of clouded awareness and afterwards he may have no recollection of the event (see also déjà vu, jamais vu). A number of these symptoms are due to scarring and atrophy (mesial temporal sclerosis) affecting the temporal lobe.The different forms of epilepsy can be controlled by the use of antiepileptic drugs (see anticonvulsant). Surgical resection of focal epileptogenic lesions in the brain is appropriate in a strictly limited number of cases.• epileptic adj. n.* * *
ep·i·lep·sy (epґĭ-lep″se) [Gr. epilēpsia seizure] any of a group of syndromes characterized by paroxysmal transient disturbances of the brain function that may be manifested as episodic impairment or loss of consciousness, abnormal motor phenomena, psychic or sensory disturbances, or perturbation of the autonomic nervous system. A single episode is called a seizure (q.v.). Many types of epilepsy are combinations of different kinds of seizures. Epilepsy is classified as either symptomatic or idiopathic according to whether the cause is known or unknown. Both of these types may be further subdivided into partial and generalized types depending on whether the seizures begin with localized, limited brain dysfunction or with widespread brain dysfunction.
Medical dictionary. 2011.
