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|LETTER TO EDITOR
|Year : 2014 | Volume
| Issue : 2 | Page : 224-226
Absence status epilepsy: Report of a rare electro-clinical syndrome
Rajesh Shankar Iyer, SR Nisha
Department of Neurology, K. G. Hospital and Post Graduate Medical Institute, Coimbatore, Tamil Nadu, India
|Date of Submission||08-Jan-2014|
|Date of Decision||08-Jan-2014|
|Date of Acceptance||06-Apr-2014|
|Date of Web Publication||14-May-2014|
Rajesh Shankar Iyer
Department of Neurology, K. G. Hospital and Post Graduate Medical Institute, Coimbatore, Tamil Nadu
Source of Support: None, Conflict of Interest: None
|How to cite this article:|
Iyer RS, Nisha S R. Absence status epilepsy: Report of a rare electro-clinical syndrome. Neurol India 2014;62:224-6
We report a patient with "absence status epilepsy" and discuss the features specific to this syndrome.
A 49-year-old presented with an acute confusional state, which lasted for more than 24 hours. There was no family history of seizures. From the age of 16, he started getting generalized tonic-clonic seizures (GTCS) at yearly intervals for 5 years, which subsequently became very infrequent. He was on 500 mg of sodium valproate. From the age of 20, he used to have episodes of confusion and unresponsiveness lasting for hours precipitated by sleep deprivation and emotional disturbances. He used to recover after a nap. These episodes became more frequent and prolonged, interfering with official work and necessitating multiple hospital admissions. There was no history of myoclonic jerks. At admission, he was confused. An urgent video-electroencephalography (EEG) was performed, which showed continuous runs of generalized spike-wave (SW) discharges at 3 Hz [Figure 1]a. He was partially responsive during these events and the discharges became discontinuous when aroused [Figure 1]b. Intravenous lorazepam 2 mg aborted the absence status [Figure 2]a. Subsequently he had intermittent runs of generalized SW discharges at 3 Hz lasting 10-20 seconds, which tapered-off over the next two hours when he recovered completely clinically and electrically. The inter-ictal record showed frontally dominant and generalized fast SW discharges [Figure 2]b suggestive of idiopathic generalized epilepsies (IGE). Hyperventilation and photic stimulation did not activate the discharges. Magnetic resonance imaging (MRI) of brain was normal and ring chromosome-20 was negative. He was put on 1 gm of sodium valproate and is event-free for the past six months.
|Figure 1: EEG showing continuous runs of 3 Hz spike and wave discharges (a) with periods of discontinuity on asking questions (b)|
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|Figure 2: EEG following intravenous lorazepam showing disappearance of the status. (a) Interictal EEG showing the generalized discharges suggesting Idiopathic Generalized Epilepsy (b)|
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Absence status epilepticus (AS) is a prolonged and non-convulsive seizure occurring in various circumstances. International League Against Epilepsy (ILAE) diagnostic scheme considers AS as a subtype of generalized status epilepticus.  Typical AS, occurs in the setting of all IGEs, especially in juvenile absence epilepsy (JAE), and atypical AS occurs in symptomatic generalized epilepsies. In 2008, Genton et al., described a new epilepsy syndrome in 11 patients with AS as their predominant or only seizure manifestation and so he proposed the name "absence status epilepsy". 
Herein, we describe a patient in whom the main seizure type is recurrent AS, infrequent GTCS, and no typical absences (TA). The onset of AS is after puberty and the prognosis is favorable on adequate treatment. Emotional disturbances, sleep deprivation and inadequate dose of sodium valproate were the triggering factors. The EEG findings as well as normal neurological and MRI findings supported IGE. Our patient is different from the well-known syndromes of IGE associated with AS, namely Juvenile myoclonic epilepsy (JME), JAE or IGE with phantom absences. , His electro-clinical features fit into the AS syndrome, described by Genton and colleagues. 
Absence status epilepsy is described with onset in puberty or early adulthood. The predominant seizure type is recurrent AS. Unlike the other better known absence syndromes, TAs are extremely rare or absent. GTCS is infrequent. This syndrome lacks positive family history. There is no photoparoxysmal response, and activation to hyperventilation is rare. The interictal EEG shows normal background activity and generalized spike and wave, and polyspike and wave discharges of 2-4 Hz frequency. The seizure control is generally excellent with adequate doses of sodium valproate.
This atypical presentation of prolonged confusional state would make us think of complex partial status resulting in the use of inappropriate drugs. Also, inadequate dosage of drugs including that of sodium valproate could increase the incidence of AS and GTCS. Recognizing AS as a separate syndrome would thus help in earlier identification and appropriate and adequate treatment.
| » References|| |
|1.||Engel J Jr. International League Against Epilepsy (ILAE). A proposed diagnostic scheme for people with epileptic seizures and with epilepsy: Report of the ILAE Task Force on Classification and Terminology. Epilepsia 2001;42:796-803. |
|2.||Genton P, Ferlazzo E, Thomas P. Absence status epilepsy: Delineation of a distinct idiopathic generalized epilepsy syndrome. Epilepsia 2008;49:642-9. |
|3.||Agathonikou A, Panayiotopoulos CP, Giannakodimos S, Koutroumanidis M. Typical absence status in adults: Diagnostic and syndromic considerations. Epilepsia 1998;39:1265-76. |
|4.||Panayiotopoulos CP, Koutroumanidis M, Giannakodimos S, Agathonikou A. Idiopathic generalized epilepsy in adults manifests by phantom absences, generalised tonic-clonic seizures, and frequent absences status. J Neurol Neurosurg Psychiatry 1997;63:622-7. |
[Figure 1], [Figure 2]