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Absence seizure
Absence seizures are one of several kinds of generalized seizures. Absence seizures are characterized by a brief loss and return of consciousness, generally not followed by a period of lethargy (i.e. without a notable postictal state). Absence seizures are most common in children. They affect both sides of the brain.
In the past, absence epilepsy was referred to as "pyknolepsy," a term derived from the Greek word "pyknos," signifying "extremely frequent" or "grouped". These seizures are sometimes referred to as petit mal seizures (from the French for "little illness", a term dated to the late 18th century); however, usage of this terminology is no longer recommended.
Childhood absence epilepsy represents a significant portion, accounting for approximately 10 to 17%, of all cases of childhood-onset epilepsy, establishing it as the most common form of pediatric epilepsy. This syndrome is characterized by daily occurrences of frequent but brief episodes of staring spells. These episodes typically commence between the ages of 4 and 8 years and manifest in otherwise seemingly healthy children. On classic electroencephalograms (EEGs), distinct patterns emerge, featuring generalized spike-wave bursts occurring at a frequency of 3 Hz, accompanied by normal background brain activity. Despite sometimes being mistakenly perceived as a benign type of epilepsy, childhood absence epilepsy is associated with varying rates of remission. Children affected by this condition often experience cognitive deficits and encounter enduring psychosocial challenges in the long term.
The incidence of absence seizures in the United States is 1.9–8 cases per 100,000 population. The morbidity from typical absence seizures is related to the frequency and duration of the seizures, as well as to the patient's activities; effective treatment ameliorates these factors. Educational and behavioral problems are sequelae of frequent, unrecognized seizures. No deaths result directly from absence seizures. However, if an individual suffers an absence seizure while driving or operating dangerous machinery, a fatal accident may occur.
Absence seizures affect between 0.7 and 4.6 per 100,000 in the general population and 6 to 8 per 100,000 in children younger than 15 years. Childhood absence seizures account for 10% to 17% of all absence seizures. Onset is between 4 and 10 years and peaks at 5 to 7 years. It is more common in girls than in boys.
An absence seizure is specifically caused by multifactorial inheritance. The voltage-gated T-type calcium channel is regulated by Gamma-aminobutyric acid receptor subunit gamma-2 (GABRG2), GABRG3, and CACNA1A2 genes. Inheritance of these genes is involved in the etiology (cause) of absence seizure. The commonly held belief is that the genetic factor is the primary cause of childhood absence epilepsy. Furthermore, patients with childhood absence epilepsy have also been reported to exhibit certain copy number variations (CNVs), such as 15q11.2, 15q13.3, and 16p13.11 microdeletions. Almost 25% of children suffering from absence seizure has a relative that suffers from seizures. Some specific anticonvulsant drugs such as phenytoin, carbamazepine, and vigabatrin have been identified to raise the chances of experiencing absence seizures.
The clinical manifestations of absence seizures vary significantly among patients. Impairment of consciousness is the essential symptom, and may be the only clinical symptom, but this can be combined with other manifestations. The hallmark of the absence seizures is abrupt and sudden-onset impairment of consciousness, interruption of ongoing activities, a blank stare, possibly a brief upward rotation of the eyes. If the patient is speaking, speech is slowed or interrupted; if walking, they stand transfixed; if eating, the food will stop on its way to the mouth. Usually, the patient will be unresponsive when addressed. In some cases, attacks are aborted when the patient is called. The attack lasts from a few seconds to half a minute and evaporates as rapidly as it commenced. Absence seizures generally are not followed by a period of disorientation or lethargy (postictal state), in contrast to the majority of seizure disorders. If the patient has jerking gestures during the seizure this might be the indication of another type of seizure occurring onward with the absence seizure.
Mixed forms of absence frequently occur. These seizures can happen a few times a day or in some cases, hundreds of times a day, to the point that the person cannot concentrate in school or in other situations requiring sustained, concentrated attention.
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Absence seizure AI simulator
(@Absence seizure_simulator)
Absence seizure
Absence seizures are one of several kinds of generalized seizures. Absence seizures are characterized by a brief loss and return of consciousness, generally not followed by a period of lethargy (i.e. without a notable postictal state). Absence seizures are most common in children. They affect both sides of the brain.
In the past, absence epilepsy was referred to as "pyknolepsy," a term derived from the Greek word "pyknos," signifying "extremely frequent" or "grouped". These seizures are sometimes referred to as petit mal seizures (from the French for "little illness", a term dated to the late 18th century); however, usage of this terminology is no longer recommended.
Childhood absence epilepsy represents a significant portion, accounting for approximately 10 to 17%, of all cases of childhood-onset epilepsy, establishing it as the most common form of pediatric epilepsy. This syndrome is characterized by daily occurrences of frequent but brief episodes of staring spells. These episodes typically commence between the ages of 4 and 8 years and manifest in otherwise seemingly healthy children. On classic electroencephalograms (EEGs), distinct patterns emerge, featuring generalized spike-wave bursts occurring at a frequency of 3 Hz, accompanied by normal background brain activity. Despite sometimes being mistakenly perceived as a benign type of epilepsy, childhood absence epilepsy is associated with varying rates of remission. Children affected by this condition often experience cognitive deficits and encounter enduring psychosocial challenges in the long term.
The incidence of absence seizures in the United States is 1.9–8 cases per 100,000 population. The morbidity from typical absence seizures is related to the frequency and duration of the seizures, as well as to the patient's activities; effective treatment ameliorates these factors. Educational and behavioral problems are sequelae of frequent, unrecognized seizures. No deaths result directly from absence seizures. However, if an individual suffers an absence seizure while driving or operating dangerous machinery, a fatal accident may occur.
Absence seizures affect between 0.7 and 4.6 per 100,000 in the general population and 6 to 8 per 100,000 in children younger than 15 years. Childhood absence seizures account for 10% to 17% of all absence seizures. Onset is between 4 and 10 years and peaks at 5 to 7 years. It is more common in girls than in boys.
An absence seizure is specifically caused by multifactorial inheritance. The voltage-gated T-type calcium channel is regulated by Gamma-aminobutyric acid receptor subunit gamma-2 (GABRG2), GABRG3, and CACNA1A2 genes. Inheritance of these genes is involved in the etiology (cause) of absence seizure. The commonly held belief is that the genetic factor is the primary cause of childhood absence epilepsy. Furthermore, patients with childhood absence epilepsy have also been reported to exhibit certain copy number variations (CNVs), such as 15q11.2, 15q13.3, and 16p13.11 microdeletions. Almost 25% of children suffering from absence seizure has a relative that suffers from seizures. Some specific anticonvulsant drugs such as phenytoin, carbamazepine, and vigabatrin have been identified to raise the chances of experiencing absence seizures.
The clinical manifestations of absence seizures vary significantly among patients. Impairment of consciousness is the essential symptom, and may be the only clinical symptom, but this can be combined with other manifestations. The hallmark of the absence seizures is abrupt and sudden-onset impairment of consciousness, interruption of ongoing activities, a blank stare, possibly a brief upward rotation of the eyes. If the patient is speaking, speech is slowed or interrupted; if walking, they stand transfixed; if eating, the food will stop on its way to the mouth. Usually, the patient will be unresponsive when addressed. In some cases, attacks are aborted when the patient is called. The attack lasts from a few seconds to half a minute and evaporates as rapidly as it commenced. Absence seizures generally are not followed by a period of disorientation or lethargy (postictal state), in contrast to the majority of seizure disorders. If the patient has jerking gestures during the seizure this might be the indication of another type of seizure occurring onward with the absence seizure.
Mixed forms of absence frequently occur. These seizures can happen a few times a day or in some cases, hundreds of times a day, to the point that the person cannot concentrate in school or in other situations requiring sustained, concentrated attention.