XXXIIIe congres de l'association des
pédiatres de langue francaise
Beyrouth, Liban 9-12, avr. 2002

ABSENCES

Purpose: The Purpose Of This Abstract Is To Highlight The Etiologies; The Mechanisms, And The Differential Diagnosis Of Absences, So Leading To Restrict The Use Of Unnecessary Antiepileptic Drugs AED; An Issue which is Not Very Clear In The Literature.

Many Physicians Consider Any Case of Staring As Epileptic Absences . However Paroxysmal Blank Spells Could Be Either Epileptics Or Non Epileptics . When Epileptics They Could Be : Typical Absences TAs, Atypical Abscences ATAs Or Complex Partial Seizures of Frontal Or Temporal Origin . Atypical Absences Are Usually Part Of Different Epileptic Syndromes Like : Lennox - Gastaut , Dravet , Continuous Spikes And Waves During Slow Sleep , Doose and Atypical Benign Partial Epilepsy .

Typical Absences, Four Epileptic Syndromes With TAs Have Been Recognized By The International League Against Epilepsy :

1- Childhood Absences Epilepsy CAE : The Eyes May Stare But They Also May Move During The Ictus, Particularly If The Child Is Loudly Called By Name. The Interictal Electroencephalogram EEG, May Show Rhythmic Posterior Delta Activity. The Duration Is No Less Than 4 Seconds SEC . There Are No Myoclonic Jerks MJ, No Generalized Tonico- Clonic Seizures GTCS, No Photosensitivity, and no EEG polyspikes and fragmentation.

2- Juvenile Absences Epilepsy JAE : It Appears That GTCS Occur In 80 % And MJ In 20 % Of Patients With JAE. The EEG Showed A High Incidence Of photosensitivity 21% And Polyspikes 33%. It is probably a life long disease .

3- Juvenile Myoclonic Epilepsy JME: It Is Characterized By Myoclonic Jerks On Awakening And The Absences Are Not Discernible; And Characteristically The EEG Discharges Are Often Fragmented With "Ws" (Multiple Spikes Having The Appearance Of Compressed "Ws".)

4- Myoclonic Absence Epilepsy MAE : The Age Of Onset Varies From 11 Months To 12 Years. Characteristically It Has A Rhythmic MJ Mainly Of The Upper Extremities. Eyelid Twitching Is Practically Absent, But Perioral Myoclonias Are Frequent . In 2/3 of Cases GTCS and Drop Attacks May Occur.

There May Be More Epileptic Syndrome With TAs Awaiting Further Studies And Confirmation:

1-Eyelid Myoclonia With Absences EMA : Is The Easiest Of All Because It Is Betrayed By The Characteristic Eyelid Myoclonia , That Once Seen Is Never Forgotten. It Consists Of Marked, Rhythmic, And Fast Jerks Of The Eyelids ,Often With Upward Jerking Of The Eyeballs And The Head . The EEG Is Mainly Of Polyspikes Type. Seizures Occur Mainly After Eye Closure . All Patients Are Photosensitive . Total Darkness Abolishes The Eye Closure-Related EEG Abnormalities .

2- Perioral Myoclonia With Absences PMA: That Consists Of Protrusion Of The Lips And Twitching Of The Corner Of The Mouth : All Patients Develop GTCS, And In Half Of Them GTCS Precede The Onset Of Absences ; As Well As EEG Irregularities .

3-The Syndrome Of Phantom Absences And GTCS : The Onset Is After 15 Years. Neither MJ, Nor Phothosensitivity Occurs In This Syndrome .GTCS Are Consistently Preceded By Absence Status.

4- Photo - And Pattern -Induced Absences : Eyelid Myoclonia Are Consistently Precipitated By Photic Stimulation. It Is Associated With A Poor Prognosis .

5- Absences With Single Myoclonic Jerk: It Appears In Early Childhood And Continues In Adult Life 6- Symptomatic And Cryptogenic Absences : The Mesial Surfaces Of The Frontal Lobe Are Most Likely To Generate TAs.

Non Epileptic Staring Spells: They Could Be Either Of Non Cerebral Origin Like: Benign Paroxysmal Vertigo And Gastroesophageal Reflux , Or More Commonly Of Cerebral Origin with different Mechanisms:

a- Anoxic (Pre- Syncope , Valsalva Manoeuvre, Pallid Form Of Breath Holding Spells With Inaudible Cry, Paroxysmal Attacks Of Cough In Cystic Fibrosis, Hyperventilation - Induced Unresponsiveness, Arrhythmia.

b- Psychic : Anxiety Emotionally Disturbed Children, Day Dreams :Where Abrupt Or Startling Stimuli Immediately Abort Daydreaming Attacks, But Not Absences Seizures . Gratification Phenomenas : More Dramatic Than Day- Dreams Of Older People Are The Complex Ritualistic Trances Of Older Infants And Toddlers . Sometimes It Looks As If The Child Has Eidetic Imagery And Is Watching A Television In The Sky . Mostly Parents Can "Swith Off " The Program As It Were By Passing Their Hand In Front Of The Child'S Face; When They Cannot , Diagnosis Is More Difficult.)

c- Toxic/Metabolic (Hypoglycemia, Sedatives As AED, Phenothiazine, Toluene Inhalation).

d- Hypnic: (Sleep Deprivation, Obstructive Sleep Apnea , Narcolepsy).

e- Confusional Migraine: That Can Be Confused With Absences Status.

f- Neurologic (Mentally Disabled Children, Subacute Sclerosing Panencephalitis ).

Conclusion: We Conclude That Not Every Case Of Staring Is Epileptic And Not Every Epileptic Absence Is A Benign Form Of The Childhood Absence Epilepsy CAE . Many TAs May Be: Associated With Mental Retardation, Resistant To Treatment And, Finally, A Life Long Disease.