What is absence status epilepticus (SE)?

Updated: Feb 13, 2018
  • Author: Julie L Roth, MD; Chief Editor: Stephen A Berman, MD, PhD, MBA  more...
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On clinical presentation, a clear change in the level of consciousness is observed in patients with absence SE. Most patients are not comatose but are lethargic and confused, with decreased spontaneity and slow speech. Absence SE is also known as absence stupor because of the apparent state of low alertness.

The ictal electroencephalograph (EEG) during typical absence SE demonstrates generalized spike and wave discharges. The frequency may be slower than 3 Hz, and the waveforms (though bilaterally synchronous) are often irregular, poorly formed, and discontinuous, especially in the late stages. In adults and in some children, the apparently bisynchronous EEG discharges may represent complex partial SE as opposed to true absence SE.

About 2.6% of patients with absence seizures have had an episode of absence SE earlier in their lives. [22] Approximately 10% of adults with childhood-onset absence seizures experience absence SE. [23] About 75% of all cases of absence SE occur before the age of 20 years. When it occurs in adults, the patients are often elderly. The mean age of onset of absence SE in adults is 51 years.

Typical absence SE that occurs in children or adolescents who have primary or idiopathic generalized epilepsy (which includes absence seizures) readily responds to treatment. In contrast, absence SE in the symptomatic, primary generalized epilepsies (eg, Lennox-Gastaut syndrome) is often more difficult to control.

Four issues should be considered in the differential diagnoses of absence SE. First, complex partial SE usually manifests with recurring cycles of 2 separate phases: ictal and interictal. In contrast, absence SE usually occurs as 1 continuous episode of variable intensity.

Second, stereotyped automatisms can be seen in both complex partial and absence SE, though they tend to be richer in complex partial SE than in absence SE. Anxiety, aggression, fear, and irritability may be most common in complex partial SE, but they can be seen in both types.

Third, EEG is the best way to differentiate absence SE from complex partial SE.

Fourth, other possibilities include a postictal state and encephalopathies from toxic-metabolic causes, drugs, trauma, or infection. Psychiatric causes should be considered.

No deaths or long-term morbidity due to typical absence SE have been reported. Whether absence SE in children with developmental dementia and myoclonic/astatic epilepsy is injurious to the brain is controversial. Differentiating absence SE from other causes is important because many mimics of absence SE can lead to irreversible neuronal damage if they are not aggressively treated.

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