- Absence seizure
DiseaseDisorder infobox
Name = Absence seizure
ICD10 = ICD10|G|40|3|g|40
ICD9 = ICD9|345.0
ICDO =
Caption =
OMIM =
OMIM_mult =
MedlinePlus = 000696
eMedicineSubj = neuro
eMedicineTopic = 3
DiseasesDB = 32994
MeshID = D004832Absence seizures are one of several kinds of
seizure s. These seizures are sometimes referred to as petit mal seizures (from the French for "little illness", a term dating from the late 1700s [cite journal |url=http://www3.interscience.wiley.com/journal/119712622/abstract |title=Reflections on the Concept of Petit Mai |last=Daly |first=D. D. |date=1968 |journal=Epilepsia |publisher=Elsevier Publishing Company, Amsterdam |volume=9 |issue=3 |pages=175-178 |DOI=10.1111/j.1528-1157.1968.tb04618.x |accessdate=2008-10-03] ).In absence seizures, the person may appear to be staring into space with or without jerking or twitching movements of the
eye muscles . These periods last for seconds, or even tens of seconds. Those experiencing absence seizures sometimes move from one location to another without any purpose. Under normal circumstances thalamocorticaloscillations maintain normalconsciousness of an individual, however in certain circumstances the normal pattern can become disrupted; thereby leading to an episode of absence.Drugs , such asethosuximide work by binding to t-type Ca2+ channels on thalamicneurones to modify these oscillations and prevent these episodes from occurring.Types
Absence seizures may occur in several forms of
epilepsy . Absence epilepsy refers to epilepsy in which the only seizures are absence seizures. Absence epilepsy is often characterized by age of onset, e.g.,childhood absence epilepsy for epilepsy beginning in childhood between the ages of 4 and 12. Absence epilepsy has also been termed pyknolepsy (from the Greek "pyknos", meaning closely packed, dense, or aggregated) and was commonly used in early 20th century German psychiatry [cite journal |last=Sauer |first=H. |publication-date=1916 |title=Uber gehaufte kleine Anfalle by Kindern (pyknolepsie) |journal=Mschr Psychiatr Neurol |volume=40 |pages=276-300]Epilepsy is the most common cause of recurrent seizures, where seizures are single events that reoccur with seemingly random frequency. Single seizures can be caused by blows to the head, fever (
febrile seizure ), reactions to medications, tumours, or as a symptom of a larger disease, among other causes.Just as there are many different kinds of seizures, there are many different kinds of epilepsy. Doctors have identified hundreds of different epilepsy syndromes - disorders characterized by a specific set of symptoms that include epilepsy. Some of these syndromes appear to be
hereditary . For other syndromes, the cause is unknown. Epilepsy syndromes are frequently described by their symptoms or by where in thebrain they originate. People should discuss the implications of their type of epilepsy with their doctors to understand the full range of symptoms, the possible treatments, and the prognosis.Presentation
Some people with absence epilepsy report seeing flashing or blinking lights in the corner of one or both eyes, possibly followed by a 'flash vision change', shortly before they slip into a seizure Fact|date=June 2008. Some have purposeless movements during their seizures, such as a jerking arm or rapidly blinking eyes [ [http://wrongdiagnosis.com/p/petit_mal_seizures/symptoms.htm Symptoms of Petit mal seizures] ] . Others have no outwardly noticeable symptoms except for brief times when they are "spaced out", as repeated absence seizures can cause momentary lapses of
Consciousness . Immediately after a seizure, the person will usually resume whatever he or she was doing prior to its onset.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 other situations requiring sustained, concentrated attention. Childhood absence epilepsy may stop when the child reaches puberty. Absence seizures usually have no lasting effect on intelligence or other brain function.
It is well known that bright lights, nervous, stressful, uncomfortable situations, or other strong sensory stimuli may trigger seizures.Fact|date=June 2008
Hyperventilation is also a common trigger. However, loud noises can help to either bring a person back to consciousness or keep him or her conscious.Fact|date=June 2008 Reciting one's name can be very helpful in an emergency as can repetitively asking the victim to "stay with you".Fact|date=June 2008 Such can be accomplished by counting methods, alphabets and so on.cite web |url=http://www.npi.ucla.edu/PEDSNEUROPSYCH/Epilepsy/body_epilepsy.html |title=Epilepsy |format= |work= |accessdate=]A person having an absence seizure shows no emotional expressions during the absent period.Fact|date=March 2008 While the ability to express emotion in the face may be dissociated from the experience of emotion, the lack of any emotionally charged facial expression may indicate that a certain
level of consciousness and arousal are needed to experienceemotions .A bilateral synchronous, symmetrical 3-Hz spike-and-wave discharge EEG pattern accompanies absence seizures. [cite journal |last1=Jasper |first1=H. H. |last2=Kershman |first2=J |date=1941 |title=Electroencephalographic classification of the epilepsies |journal=Arch Neurol Psychiatry |volume=45 |page=903–943]
Treatment
The primary goal of treatment of recurrent absence seizures is to prevent accidental injuries that may occur through the lapses of consciousness that accompany seizures. For those with frequent seizures treatment seeks to prevent the seizures from interfering with learning or other activities of daily life.
The purpose of medication for treatment of absence seizures is to accomplish the goals above, by eliminating or reducing the frequency of the absence seizures, without causing side-effects more serious than the epilepsy itself.
Certain anticonvulsant drugs are used to minimize the number of seizures episodes. Absence seizures appear to respond well to
divalproex sodium (trade name: Depakote),ethosuximide (trade name: Zarontin), andlamotrigine (Lamictal). Each of these medications has potential side effects, some of them possibly serious, which makes it important that the patient and/or their caregivers understand the specific medication they have been prescribed.For treatment of absence seizures there is insufficient evidence to know if any of the available medications is best. i.e., which has the best combination of safety and efficacy for a particular patient.cite web |url=http://www.cochrane.org/reviews/en/ab003032.html |title=Ethosuximide, sodium valproate or lamotrigine for absence seizures in children and adolescents |format= |work= |accessdate=] Nor is it known how long medication must be continued before an off-medication trial should be conducted to determine if the individual has outgrown the absence seizures, as is often the case with children.
To date, there have been no published results of any large, double-blind, placebo-controlled studies comparing the efficacy and safety of these or any other medications for absence seizures.Fact|date=June 2008
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