Absence Epilepsy Seizures (Petit Mal Crisis) – Clinical Presentation
Absence seizures represent a type of generalized epilepsy seizures and were first described by Poupart in 1705, and later by Tissot in 1770, who named this crisis as petit accesses. In 1824, Calmeil used the term absence to describe this type of generalized epilepsy seizures and in 1935, Gibbs, Davis, and Lennox have established a link between absence crisis and loss of consciousness.
Absence epilepsy seizures occur mainly in generalized epilepsy with onset in childhood and may be associated with tonic, clonic or atonic component, with automatisms or autonomic signs.This type of seizures are brief, are lasting just a few seconds (pyknoleptic) and for this reason some children can experience many such seizures per day. In other cases of epilepsy, particularly those with an older age of onset, absence seizures last several seconds up to minutes, patients may experience only a few number of seizures per day (nonpyknoleptic or spanioleptic absence seizures).
- Absence seizures – typical or atypical;
- Absence with special features – myoclonic absence and eyelid myoclonia.
Absence Epilepsy Seizures (Petit Mal Crisis)
Absence epilepsy seizures usually occur in childhood, around the age of 2 years old, until the age of 13-14 years, when are replaced by generalized tonic-clonic epilepsy seizures.
Absence crisis have a sudden onset and interfere with normal activity, patient having no warning or postictal phase as in the case of grand mal crisis. If the patient is engaged in a motor activity such as walking, he may stop and remain motionless or he may continue walking. Typical, during an absence seizure the child or teenager abruptly ceases his activity and remain motionless, the gaze is fixed straight ahead and occasionally the eyelids may slightly flicker. This events lasts several seconds, after this episode patient resume his previous activity. If the crisis occur while the child is walking or playing, he stops and sometimes may drop objects from his hands and after several seconds will return to his previous activity. Children are not responsive during the seizure and have no memory of what happened during the crisis, they are generally unaware that the seizure has occurred. In most cases, absence crisis occur frequently in the morning.
Absence crisis usually lasts between 5 and 15 seconds, sometimes may last longer, and because it has a short duration may remain unnoticed by other family members, such a crisis may be observed on the electroencephalogram (EEG) examination.
In most cases of generalized epilepsy in children, physical and neurological examination are normal, but having the child hyperventilate for 3-5 minutes can often provoke absence seizures. This procedure can easily be performed and can represent a useful diagnostic maneuver.
Children with generalized epilepsy may have a medical history of staring spells or behavioral problems, but often absence seizures remain undiagnosed until a generalized tonic-clonic seizure has occurred, but decline in school performance may be an indication of the onset or breakthrough of absence seizures. Atypical absence seizure may lead to intellectual development delay or mental retardation.
Absence Epilepsy Seizures (Petit Mal Crisis) Clinical Forms
In medical practice, particular variants of absence epilepsy seizures are encountered, such as:
- Myoclonic absence, beside the absence crisis, the patient presents muscle contractions (myoclonic jerks);
- Akinetic absence, in which absence crisis may be associated with loss of axial muscle tone and head nodding. If crisis lasts long enough, forward flexion of the trunk may occur.